0001656423-19-000033 | 10-Q | XBRL Viewer

General and administrative

743,553

686,284

2,203,061

2,011,919

Expenses

Rental

265,603

247,989

781,091

726,108

31,147

29,677

107,980

94,039

Transaction costs

538

914

1,415

1,409

165,862

157,996

507,867

480,210

474,322

447,920

1,432,266

1,334,779

Other income (expense)

Gains (losses) on sales of real estate

(649)

(4,313)

47,528

(3,083)

(15)

7,863

766

122,552

Interest and other income

7,178

2,822

14,546

7,049

Gains (losses) from investments in securities

106

1,075

4,240

1,454

(24,038)

(28,010)

(106,471)

(95,366)

(309,837)

(277,790)

Net income attributable to noncontrolling interests

141,370

150,445

475,990

527,322

Noncontrolling interests in property partnerships

(18,470)

(14,850)

(54,782)

(46,484)

Noncontrolling interest—common units of Boston Properties Limited Partnership

(12,504)

(13,852)

(43,133)

(49,128)

Net income attributable to the Company

110,396

121,743

378,075

431,710

Preferred dividends / distributions

(2,625)

(7,875)

Net income attributable to the Company's common shareholders / unitholders

$ 107,771

$ 119,118

$ 370,200

$ 423,835

Basic earnings per common share / unit attributable to the Company's common shareholders / unitholders

Earnings Per Share, Basic

$ 0.70

$ 0.77

$ 2.40

$ 2.74

Weighted average number of common shares / units outstanding

154,577

154,440

154,553

154,414

Diluted earnings per common share / unit attributable to the Company's common shareholders / unitholders

Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit)

$ 0.70

$ 0.77

$ 2.39

$ 2.74

Weighted average number of common and common equivalent shares / units outstanding (in shares / units)

154,820

154,678

154,847

154,652

Revenue

Lease

$ 692,225

$ 2,051,665

Base rent

$ 525,875

$ 1,561,821

Recoveries from tenants

102,424

292,801

General and administrative

743,553

686,284

2,203,061

2,011,919

Expenses

Rental

265,603

247,989

781,091

726,108

31,147

29,677

107,980

94,039

Transaction costs

538

914

1,415

1,409

164,020

156,056

501,901

474,383

472,480

445,980

1,426,300

1,328,952

Other income (expense)

Gains (losses) on sales of real estate

(649)

(4,313)

47,528

(3,083)

(15)

9,154

915

126,831

Interest and other income

7,178

2,822

14,546

7,049

Gains (losses) from investments in securities

106

1,075

4,240

1,454

(22,272)

(28,010)

(106,471)

(95,366)

(309,837)

(277,790)

Net income attributable to noncontrolling interests

143,212

153,676

483,871

537,428

Noncontrolling interests in property partnerships

(18,470)

(14,850)

(54,782)

(46,484)

Net income attributable to the Company

124,742

138,826

429,089

490,944

Preferred dividends / distributions

(2,625)

(7,875)

Net income attributable to the Company's common shareholders / unitholders

$ 122,117

$ 136,201

$ 421,214

$ 483,069

Basic earnings per common share / unit attributable to the Company's common shareholders / unitholders

Earnings Per Share, Basic

$ 0.71

$ 0.79

$ 2.45

$ 2.81

Weighted average number of common shares / units outstanding

172,215

171,928

172,183

171,904

Diluted earnings per common share / unit attributable to the Company's common shareholders / unitholders

Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit)

$ 0.71

$ 0.79

$ 2.44

$ 2.81

Weighted average number of common and common equivalent shares / units outstanding (in shares / units)

172,458

172,166

172,477

172,142

Parking and Other [Member]

Revenue

Parking and Other [Member] | Boston Properties Limited Partnership

$ 25,582

$ 26,552

$ 76,807

$ 79,590

Revenue

25,582

26,552

76,807

79,590

Hotel [Member]

Revenue

^[1]

13,014

13,664

36,796

37,373

Expenses

Hotel [Member] | Boston Properties Limited Partnership

8,743

8,828

25,686

25,642

Revenue

13,014

13,664

36,796

37,373

Expenses

Development and Management Services [Member]

8,743

8,828

25,686

25,642

Revenue

10,303

15,253

29,566

32,963

Expenses

Development and Management Services [Member] | Boston Properties Limited Partnership

2,429

2,516

8,227

7,371

Revenue

10,303

15,253

29,566

32,963

Expenses

Direct reimbursements of payroll and related costs from management services contracts

2,429

2,516

8,227

7,371

Revenue

Direct reimbursements of payroll and related costs from management services contracts | Boston Properties Limited Partnership

2,429

2,516

8,227

7,371

Expenses

Rental

261,592

244,265

769,184

717,199

Revenue

$ 2,429

$ 2,516

$ 8,227

$ 7,371

[1]	Rental Revenue is equal to Total Revenue per the Company’s Consolidated Statements of Operations, less Development and Management Services Revenue and Direct Reimbursements of Payroll and Related Costs from Management Services Contracts Revenue per the Consolidated Statements of Operations.

Consolidated Statements Of Comprehensive Income - USD ($)
$ in Thousands

3 Months Ended

9 Months Ended

Sep. 30, 2019

Sep. 30, 2018

Sep. 30, 2019

Sep. 30, 2018

Effective portion of interest rate contracts

$ 141,370

$ 150,445

$ 475,990

$ 527,322

Other comprehensive income (loss):

(2,253)

1,325

(9,307)

1,325

Amortization of interest rate contracts

^[1]

1,666

4,998

Other comprehensive income (loss)

(587)

2,991

(4,309)

6,323

Comprehensive income

140,783

153,436

471,681

533,645

Comprehensive income attributable to noncontrolling interests

(30,974)

(28,702)

(97,915)

(95,612)

Other comprehensive (income) loss attributable to noncontrolling interests

(69)

(433)

(1,031)

Comprehensive income attributable to the Company

109,740

124,301

373,820

437,002

Effective portion of interest rate contracts

143,212

153,676

483,871

537,428

Other comprehensive income (loss):

(2,253)

1,325

(9,307)

1,325

Amortization of interest rate contracts

^[2]

1,666

4,998

Other comprehensive income (loss)

(587)

2,991

(4,309)

6,323

Comprehensive income

142,625

156,667

479,562

543,751

Comprehensive income attributable to noncontrolling interests

(18,614)

(14,994)

(55,214)

(46,916)

Comprehensive income attributable to the Company

$ 124,011

$ 141,673

$ 424,348

$ 496,835

[1]	Amounts reclassified from comprehensive income primarily to interest expense within the Boston Properties, Inc.’s Consolidated Statements of Operations.
[2]	Amounts reclassified from comprehensive income primarily to interest expense within the Boston Properties Limited Partnership’s Consolidated Statements of Operations.

Consolidated Statements Of Stockholders' Equity - USD ($)	Total	Common Stock [Member]	Preferred Stock [Member]	Additional Paid-In Capital [Member]	Dividends In Excess Of Earnings [Member]	Treasury Stock, At Cost [Member]	Accumulated Other Comprehensive (Income) Loss [Member]	Noncontrolling Interests - Common units [Member]	Noncontrolling interest - property partnerships [Member]
Equity, value at Dec. 31, 2017	$ 8,102,456,000	$ 1,543,000	$ 200,000,000	$ 6,377,908,000	$ (712,343,000)	$ (2,722,000)	$ (50,429,000)	$ 604,739,000	$ 1,683,760,000
Equity, shares at Dec. 31, 2017		154,325,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of a change in accounting principle	5,496,000				4,933,000			563,000
Redemption of operating partnership units to Common Stock, shares		60,000
Redemption of operating partnership units to Common Stock, value	0	$ 1,000		2,111,000				(2,112,000)
Allocated net income for the year	527,322,000				431,710,000			49,128,000	46,484,000
Dividends/distributions declared	(447,342,000)				(401,612,000)			(45,730,000)
Shares issued pursuant to stock purchase plan, shares		6,000
Shares issued pursuant to stock purchase plan, value	797,000			797,000
Net activity from stock option and incentive plan, shares		49,000
Net activity from stock option and incentive plan, value	30,570,000			1,354,000				29,216,000
Contributions from noncontrolling interests in property partnerships	37,148,000								37,148,000
Distributions to noncontrolling interests in property partnerships	(56,796,000)								(56,796,000)
Effective portion of interest rate contracts	1,325,000						1,190,000	135,000	0
Amortization of interest rate contracts	4,998,000						4,102,000	464,000	432,000
Reallocation of noncontrolling interest	0			18,023,000				(18,023,000)
Equity, value at Sep. 30, 2018	8,205,974,000	$ 1,544,000	200,000,000	6,400,193,000	(677,312,000)	(2,722,000)	(45,137,000)	618,380,000	1,711,028,000
Equity, shares at Sep. 30, 2018		154,440,000
Equity, value at Jun. 30, 2018	8,213,242,000	$ 1,544,000	200,000,000	6,391,460,000	(649,747,000)	(2,722,000)	(47,695,000)	621,221,000	1,699,181,000
Equity, shares at Jun. 30, 2018		154,412,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Redemption of operating partnership units to Common Stock, shares		25,000
Redemption of operating partnership units to Common Stock, value	0	$ 0		916,000				(916,000)
Allocated net income for the year	150,445,000				121,778,000			13,817,000	14,850,000
Dividends/distributions declared	(166,365,000)				(149,343,000)			(17,022,000)
Shares issued pursuant to stock purchase plan, shares		3,000
Shares issued pursuant to stock purchase plan, value	368,000			368,000
Net activity from stock option and incentive plan, shares		0
Net activity from stock option and incentive plan, value	8,440,000			754,000				7,686,000
Contributions from noncontrolling interests in property partnerships	9,616,000								9,616,000
Distributions to noncontrolling interests in property partnerships	(12,763,000)								(12,763,000)
Effective portion of interest rate contracts	1,325,000						1,190,000	135,000
Amortization of interest rate contracts	1,666,000						1,368,000	154,000	144,000
Reallocation of noncontrolling interest	0			6,695,000				(6,695,000)
Equity, value at Sep. 30, 2018	8,205,974,000	$ 1,544,000	200,000,000	6,400,193,000	(677,312,000)	(2,722,000)	(45,137,000)	618,380,000	1,711,028,000
Equity, shares at Sep. 30, 2018		154,440,000
Equity, value at Dec. 31, 2018	$ 8,213,968,000	$ 1,545,000	200,000,000	6,407,623,000	(675,534,000)	(2,722,000)	(47,741,000)	619,352,000	1,711,445,000
Equity, shares at Dec. 31, 2018	154,458,478	154,458,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of a change in accounting principle	$ (4,379,000)				(3,864,000)			(445,000)	(70,000)
Redemption of operating partnership units to Common Stock, shares		42,000
Redemption of operating partnership units to Common Stock, value	0	$ 1,000		1,434,000				(1,435,000)
Allocated net income for the year	475,990,000				378,075,000			43,133,000	54,782,000
Dividends/distributions declared	(499,934,000)				(448,343,000)			(51,591,000)
Shares issued pursuant to stock purchase plan, shares		6,000
Shares issued pursuant to stock purchase plan, value	688,000			688,000
Net activity from stock option and incentive plan, shares		66,000
Net activity from stock option and incentive plan, value	26,887,000			(2,665,000)				29,552,000
sale of an interest in property partnerships	0			(4,216,000)					4,216,000
Acquisition of noncontrolling interest in property partnership	(186,963,000)			(162,462,000)					(24,501,000)
Contributions from noncontrolling interests in property partnerships	26,968,000								26,968,000
Distributions to noncontrolling interests in property partnerships	(53,149,000)								(53,149,000)
Effective portion of interest rate contracts	(9,307,000)						(8,354,000)	(953,000)
Amortization of interest rate contracts	4,998,000						4,099,000	467,000	432,000
Reallocation of noncontrolling interest	0			34,390,000				(34,390,000)
Equity, value at Sep. 30, 2019	$ 7,995,767,000	$ 1,546,000	200,000,000	6,274,792,000	(749,666,000)	(2,722,000)	(51,996,000)	603,690,000	1,720,123,000
Equity, shares at Sep. 30, 2019	154,572,073	154,572,000
Equity, value at Jun. 30, 2019	$ 8,020,667,000	$ 1,546,000	200,000,000	6,278,961,000	(710,592,000)	(2,722,000)	(51,340,000)	608,593,000	1,696,221,000
Equity, shares at Jun. 30, 2019		154,563,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of a change in accounting principle									0
Redemption of operating partnership units to Common Stock, shares		7,000
Redemption of operating partnership units to Common Stock, value	0	$ 0		223,000				(223,000)
Allocated net income for the year	141,370,000				110,394,000			12,506,000	18,470,000
Dividends/distributions declared	(166,668,000)				(149,468,000)			(17,200,000)
Shares issued pursuant to stock purchase plan, shares		2,000
Shares issued pursuant to stock purchase plan, value	315,000			315,000
Net activity from stock option and incentive plan, shares		0
Net activity from stock option and incentive plan, value	(445,000)			(7,219,000)				6,774,000
sale of an interest in property partnerships	0			(4,216,000)					4,216,000
Acquisition of noncontrolling interest in property partnership	43,000			43,000
Contributions from noncontrolling interests in property partnerships	14,820,000								14,820,000
Distributions to noncontrolling interests in property partnerships	(13,748,000)								(13,748,000)
Effective portion of interest rate contracts	(2,253,000)						(2,022,000)	(231,000)
Amortization of interest rate contracts	1,666,000						1,366,000	156,000	144,000
Reallocation of noncontrolling interest	0			6,685,000				(6,685,000)
Equity, value at Sep. 30, 2019	$ 7,995,767,000	$ 1,546,000	$ 200,000,000	$ 6,274,792,000	$ (749,666,000)	$ (2,722,000)	$ (51,996,000)	$ 603,690,000	$ 1,720,123,000
Equity, shares at Sep. 30, 2019	154,572,073	154,572,000

Consolidated Statements of Capital and Noncontrolling Interests - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Common Stock, Shares, Outstanding	154,572,073		154,572,073			154,458,478
Cumulative effect of a change in accounting principle			$ (4,379,000)	$ 5,496,000
Effective portion of interest rate contracts	$ (2,253,000)	$ 1,325,000	(9,307,000)	1,325,000
Amortization of interest rate contracts	1,666,000	1,666,000	4,998,000	4,998,000
Acquisition of noncontrolling interest in property partnership	43,000		(186,963,000)
sale of an interest in property partnerships	0		0
Contributions from noncontrolling interests in property partnerships	14,820,000	9,616,000	26,968,000	37,148,000
Distributions to noncontrolling interests in property partnerships	(13,748,000)	$ (12,763,000)	(53,149,000)	(56,796,000)
Boston Properties Limited Partnership
Redeemable Noncontrolling Interest, Equity, Preferred, Carrying Amount	2,335,272,000		2,335,272,000			$ 2,000,591,000
Beginning Balance			5,912,323,000
Contributions from noncontrolling interests in property partnerships			26,968,000	$ 37,148,000
Ending Balance	$ 5,367,322,000		$ 5,367,322,000
General Partner [Member]
Common Stock, Shares, Outstanding	1,726,000	1,722,000	1,726,000	1,722,000	1,726,000	1,722,000	1,722,000	1,720,000
Contributions, units	0	0	3,000	1,000
Conversion of redeemable partnership units	0	0	1,000	1,000
Limited Partner [Member]
Common Stock, Shares, Outstanding	152,846,000	152,718,000	152,846,000	152,718,000	152,837,000	152,736,000	152,689,000	152,606,000
Contributions, units	2,000	3,000	69,000	53,000
Conversion of redeemable partnership units	7,000	26,000	41,000	59,000
Partners' Capital (General and Limited Partners) [Member]
Beginning Balance	$ 3,562,910,000	$ 3,820,773,000	$ 4,054,996,000	$ 3,664,436,000
Cumulative effect of a change in accounting principle	0	0	(3,864,000)	4,933,000
Contributions, value	(3,915,000)	354,000	1,787,000	2,039,000
Allocated net income for the period	109,611,000	122,384,000	378,081,000	433,941,000
Distributions	(146,843,000)	(146,718,000)	(440,468,000)	(393,737,000)
Unearned compensation	(7,205,000)	768,000	(7,980,000)	112,000
Conversion of redeemable partnership units	223,000	916,000	1,435,000	2,112,000
Adjustment to reflect redeemable partnership units at redemption value	(9,252,000)	48,622,000	(315,953,000)	133,263,000
Acquisition of noncontrolling interest in property partnership	43,000		(162,462,000)
Ending Balance	3,505,572,000	3,847,099,000	3,505,572,000	3,847,099,000
Preferred Units [Member]
Beginning Balance	193,623,000	193,623,000	193,623,000	193,623,000
Allocated net income for the period	2,625,000	2,625,000	7,875,000	7,875,000
Distributions	(2,625,000)	(2,625,000)	(7,875,000)	(7,875,000)
Ending Balance	193,623,000	193,623,000	193,623,000	193,623,000
Accumulated Other Comprehensive (Income) Loss [Member]
Beginning Balance	(51,340,000)	(47,695,000)	(47,741,000)	(50,429,000)
Effective portion of interest rate contracts	(2,022,000)	1,190,000	(8,354,000)	1,190,000
Amortization of interest rate contracts	1,366,000	1,368,000	4,099,000	4,102,000
Ending Balance	(51,996,000)	(45,137,000)	(51,996,000)	(45,137,000)
Noncontrolling interest - property partnerships [Member]
Beginning Balance	1,696,221,000	1,699,181,000	1,711,445,000	1,683,760,000
Cumulative effect of a change in accounting principle	0		(70,000)
Allocated net income for the period	18,470,000	14,850,000	54,782,000	46,484,000
Effective portion of interest rate contracts				0
Amortization of interest rate contracts	144,000	144,000	432,000	432,000
Acquisition of noncontrolling interest in property partnership			(24,501,000)
sale of an interest in property partnerships	4,216,000		4,216,000
Contributions from noncontrolling interests in property partnerships	14,820,000	9,616,000	26,968,000	37,148,000
Distributions to noncontrolling interests in property partnerships	(13,748,000)	(12,763,000)	(53,149,000)	(56,796,000)
Ending Balance	1,720,123,000	1,711,028,000	1,720,123,000	1,711,028,000
Noncontrolling interest - property partnerships [Member] \| Boston Properties Limited Partnership
Cumulative effect of a change in accounting principle			(70,000)
Total Capital [Member]
Beginning Balance	5,401,414,000	5,665,882,000	5,912,323,000	5,491,390,000
Cumulative effect of a change in accounting principle	0	0	(3,934,000)	4,933,000
Contributions, value	(3,915,000)	354,000	1,787,000	2,039,000
Allocated net income for the period	130,706,000	139,859,000	440,738,000	488,300,000
Distributions	(149,468,000)	(149,343,000)	(448,343,000)	(401,612,000)
Unearned compensation	(7,205,000)	768,000	(7,980,000)	112,000
Conversion of redeemable partnership units	223,000	916,000	1,435,000	2,112,000
Adjustment to reflect redeemable partnership units at redemption value	(9,252,000)	48,622,000	(315,953,000)	133,263,000
Effective portion of interest rate contracts	(2,022,000)	1,190,000	(8,354,000)	1,190,000
Amortization of interest rate contracts	1,510,000	1,512,000	4,531,000	4,534,000
Acquisition of noncontrolling interest in property partnership	43,000		(186,963,000)
sale of an interest in property partnerships	4,216,000		4,216,000
Contributions from noncontrolling interests in property partnerships	14,820,000	9,616,000	26,968,000	37,148,000
Distributions to noncontrolling interests in property partnerships	(13,748,000)	(12,763,000)	(53,149,000)	(56,796,000)
Ending Balance	5,367,322,000	5,706,613,000	5,367,322,000	5,706,613,000
Noncontrolling interest - Redeemable partnership units [Member]
Redeemable Noncontrolling Interest, Equity, Preferred, Carrying Amount	2,335,272,000	2,190,664,000	2,335,272,000	2,190,664,000	$ 2,324,238,000	$ 2,000,591,000	$ 2,235,432,000	$ 2,292,263,000
Cumulative effect of a change in accounting principle	0	0	(445,000)	563,000
Contributions, value	0	(3,000)	35,482,000	34,970,000
Allocated net income for the period	12,506,000	13,817,000	43,133,000	49,128,000
Distributions	(17,200,000)	(17,022,000)	(51,591,000)	(45,730,000)
Unearned compensation	6,774,000	7,689,000	(5,930,000)	(5,754,000)
Conversion of redeemable partnership units	(223,000)	(916,000)	(1,435,000)	(2,112,000)
Adjustment to reflect redeemable partnership units at redemption value	9,252,000	(48,622,000)	315,953,000	(133,263,000)
Effective portion of interest rate contracts	(231,000)	135,000	(953,000)	135,000
Amortization of interest rate contracts	$ 156,000	$ 154,000	$ 467,000	$ 464,000

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net income	$ 475,990	$ 527,322
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	507,867	480,210
Amortization of right of use assets - operating leases	1,821	0
Impairment loss	24,038	0
Non-cash compensation expense	33,253	31,700
Loss (income) from unconsolidated joint ventures	(47,528)	3,083
Distributions of net cash flow from operations of unconsolidated joint ventures	16,770	3,988
Gains from investments in securities	(4,240)	(1,454)
Non-cash portion of interest expense	16,594	15,922
Settlement of accreted debt discount on redemption of unsecured senior notes	(763)	0
Loss from early extinguishment of debt	28,010	0
Gains on sales of real estate	(766)	(122,552)
Change in assets and liabilities:
Tenant and other receivables, net	(20,677)	1,578
Note receivable	(376)	0
Accrued rental income, net	(19,327)	(41,519)
Prepaid expenses and other assets	(63,857)	(51,938)
Lease liabilities - operating leases	1,191	0
Accounts payable and accrued expenses	32,467	6,354
Accrued interest payable	(6,104)	8,860
Other liabilities	(78,449)	(1,561)
Tenant leasing costs	(76,122)	(89,366)
Total adjustments	343,802	243,305
Net cash provided by operating activities	819,792	770,627
Cash flows from investing activities:
Acquisitions of real estate	(148,912)	0
Construction in progress	(390,275)	(530,389)
Building and other capital improvements	(129,340)	(140,969)
Tenant improvements	(191,532)	(129,450)
Right of use asset - finance leases	(5,152)	0
Proceeds from sales of real estate	83,486	175,577
Capital contributions to unconsolidated joint ventures	(65,499)	(314,075)
Capital distributions from unconsolidated joint ventures	136,807	0
Cash and cash equivalents deconsolidated	(24,112)	0
Issuance of related party note receivable	0	(80,000)
Investments in securities, net	(1,937)	(761)
Net cash used in investing activities	(736,466)	(1,020,067)
Cash flows from financing activities:
Repayments of mortgage notes payable	(15,510)	(14,677)
Proceeds from unsecured senior notes	1,548,106	0
Redemption of unsecured senior notes	(699,237)	0
Borrowings on unsecured line of credit	380,000	580,000
Repayments of unsecured line of credit	(380,000)	(455,000)
Proceeds from unsecured term loan	0	500,000
Payments on finance lease obligations	(502)	0
Payments on real estate financing transaction	0	(960)
Deferred financing costs	(13,130)	(263)
Debt prepayment and extinguishment costs	(27,270)	0
Net proceeds from equity transactions	2,562	(333)
Distributions	(499,627)	(421,264)
Contributions from noncontrolling interests in property partnerships	26,968	37,148
Distributions to noncontrolling interests in property partnerships	(53,149)	(56,796)
Acquisition of noncontrolling interest in property partnership	(186,963)	0
Net cash provided by financing activities	82,248	167,855
Net increase (decrease) in cash and cash equivalents and cash held in escrows	165,574	(81,585)
Cash and cash equivalents and cash held in escrows, beginning of period	639,191	505,369
Cash and cash equivalents and cash held in escrows, end of period	804,765	423,784
Reconciliation of cash and cash equivalents and cash held in escrows:
Cash and cash equivalents, beginning of period	543,359	434,767
Cash held in escrows, beginning of period	95,832	70,602
Cash and cash equivalents, end of period	751,210	322,502
Cash held in escrows, end of period	53,555	101,282
Supplemental disclosures:
Cash paid for interest	338,033	303,203
Interest capitalized	41,253	51,594
Non-cash investing and financing activities:
Write-off of fully depreciated real estate	(86,496)	(100,118)
Additions to real estate included in accounts payable and accrued expenses	95,857	(11,746)
Right of use assets obtained in exchange for lease liabilities	287,540	0
Prepaid rent reclassified to right of use asset	15,000	0
Building and other capital improvements deconsolidated	(12,767)	0
Right of use asset - finance lease deconsolidated	(135,004)	0
Investment in unconsolidated joint venture recorded on deconsolidation	29,246	0
Lease liability - finance lease deconsolidated	119,534	0
Dividends and distributions payable	165,421	165,118
Conversions of redeemable partnership units to partners’ capital	1,435	2,112
Issuance of restricted securities to employees and directors	38,923	37,342
Boston Properties Limited Partnership
Cash flows from operating activities:
Net income	483,871	537,428
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	501,901	474,383
Amortization of right of use assets - operating leases	1,821	0
Impairment loss	22,272	0
Non-cash compensation expense	33,253	31,700
Loss (income) from unconsolidated joint ventures	(47,528)	3,083
Distributions of net cash flow from operations of unconsolidated joint ventures	16,770	3,988
Gains from investments in securities	(4,240)	(1,454)
Non-cash portion of interest expense	16,594	15,922
Settlement of accreted debt discount on redemption of unsecured senior notes	(763)	0
Loss from early extinguishment of debt	28,010	0
Gains on sales of real estate	(915)	(126,831)
Change in assets and liabilities:
Tenant and other receivables, net	(20,677)	1,578
Note receivable	(376)	0
Accrued rental income, net	(19,327)	(41,519)
Prepaid expenses and other assets	(63,857)	(51,938)
Lease liabilities - operating leases	1,191	0
Accounts payable and accrued expenses	32,467	6,354
Accrued interest payable	(6,104)	8,860
Other liabilities	(78,449)	(1,561)
Tenant leasing costs	(76,122)	(89,366)
Total adjustments	335,921	233,199
Net cash provided by operating activities	819,792	770,627
Cash flows from investing activities:
Acquisitions of real estate	(148,912)	0
Construction in progress	(390,275)	(530,389)
Building and other capital improvements	(129,340)	(140,969)
Tenant improvements	(191,532)	(129,450)
Right of use asset - finance leases	(5,152)	0
Proceeds from sales of real estate	83,486	175,577
Capital contributions to unconsolidated joint ventures	(65,499)	(314,075)
Capital distributions from unconsolidated joint ventures	136,807	0
Cash and cash equivalents deconsolidated	(24,112)	0
Issuance of related party note receivable	0	(80,000)
Investments in securities, net	(1,937)	(761)
Net cash used in investing activities	(736,466)	(1,020,067)
Cash flows from financing activities:
Repayments of mortgage notes payable	(15,510)	(14,677)
Proceeds from unsecured senior notes	1,548,106	0
Redemption of unsecured senior notes	(699,237)	0
Borrowings on unsecured line of credit	380,000	580,000
Repayments of unsecured line of credit	(380,000)	(455,000)
Proceeds from unsecured term loan	0	500,000
Payments on finance lease obligations	(502)	0
Payments on real estate financing transaction	0	(960)
Deferred financing costs	(13,130)	(263)
Debt prepayment and extinguishment costs	(27,270)	0
Net proceeds from equity transactions	2,562	(333)
Distributions	(499,627)	(421,264)
Contributions from noncontrolling interests in property partnerships	26,968	37,148
Distributions to noncontrolling interests in property partnerships	(53,149)	(56,796)
Acquisition of noncontrolling interest in property partnership	(186,963)	0
Net cash provided by financing activities	82,248	167,855
Net increase (decrease) in cash and cash equivalents and cash held in escrows	165,574	(81,585)
Cash and cash equivalents and cash held in escrows, beginning of period	639,191	505,369
Cash and cash equivalents and cash held in escrows, end of period	804,765	423,784
Reconciliation of cash and cash equivalents and cash held in escrows:
Cash and cash equivalents, beginning of period	543,359	434,767
Cash held in escrows, beginning of period	95,832	70,602
Cash and cash equivalents, end of period	751,210	322,502
Cash held in escrows, end of period	53,555	101,282
Supplemental disclosures:
Cash paid for interest	338,033	303,203
Interest capitalized	41,253	51,594
Non-cash investing and financing activities:
Write-off of fully depreciated real estate	(86,496)	(100,118)
Additions to real estate included in accounts payable and accrued expenses	95,857	(11,746)
Right of use assets obtained in exchange for lease liabilities	287,540	0
Prepaid rent reclassified to right of use asset	15,000	0
Building and other capital improvements deconsolidated	(12,767)	0
Right of use asset - finance lease deconsolidated	(135,004)	0
Investment in unconsolidated joint venture recorded on deconsolidation	29,246	0
Lease liability - finance lease deconsolidated	119,534	0
Dividends and distributions payable	165,421	165,118
Conversions of redeemable partnership units to partners’ capital	1,435	2,112
Issuance of restricted securities to employees	$ 38,923	$ 37,342

Organization

9 Months Ended

Sep. 30, 2019

Organization, Consolidation and Presentation of Financial Statements [Abstract]

Organization

1. Organization

Boston Properties, Inc., a Delaware corporation, is a fully integrated, self-administered and self-managed real estate investment trust (“REIT”). Boston Properties, Inc. is the sole general partner of Boston Properties Limited Partnership, its operating partnership, and at September 30, 2019 owned an approximate 89.6% (89.7% at December 31, 2018) general and limited partnership interest in Boston Properties Limited Partnership. Unless stated otherwise or the context requires, the “Company” refers to Boston Properties, Inc. and its subsidiaries, including Boston Properties Limited Partnership, and its consolidated subsidiaries. Partnership interests in Boston Properties Limited Partnership include:


•	common units of partnership interest (also referred to as “OP Units”),


•	long term incentive units of partnership interest (also referred to as “LTIP Units”), and


•	preferred units of partnership interest (also referred to as “Preferred Units”).

Unless specifically noted otherwise, all references to OP Units exclude units held by Boston Properties, Inc. A holder of an OP Unit may present such OP Unit to Boston Properties Limited Partnership for redemption at any time (subject to restrictions agreed upon at the time of issuance of OP Units to particular holders that may restrict such redemption right for a period of time, generally one year from issuance). Upon presentation of an OP Unit for redemption, Boston Properties Limited Partnership is obligated to redeem the OP Unit for cash equal to the value of a share of common stock of Boston Properties, Inc. (“Common Stock”). In lieu of a cash redemption, Boston Properties, Inc. may elect to acquire the OP Unit for one share of Common Stock. Because the number of shares of Common Stock outstanding at all times equals the number of OP Units that Boston Properties, Inc. owns, one share of Common Stock is generally the economic equivalent of one OP Unit, and the quarterly distribution that may be paid to the holder of an OP Unit equals the quarterly dividend that may be paid to the holder of a share of Common Stock.

The Company uses LTIP Units as a form of equity-based award for annual long-term incentive equity compensation. The Company has also issued LTIP Units to employees in the form of (1) 2012 outperformance plan awards (“2012 OPP Units”) and (2) 2013, 2014, 2015, 2016, 2017, 2018 and 2019 multi-year, long-term incentive program awards (also referred to as “MYLTIP Units”), each of which, upon the satisfaction of certain performance and vesting conditions, is convertible into one OP Unit. The three-year measurement periods for the 2012 OPP Units, 2013 MYLTIP Units, 2014 MYLTIP Units, 2015 MYLTIP Units and 2016 MYLTIP Units expired on February 6, 2015, February 4, 2016, February 3, 2017, February 4, 2018 and February 9, 2019, respectively, and Boston Properties, Inc.’s total stockholder return (“TSR”) was sufficient for employees to earn and therefore become eligible to vest in a portion of the awards. Unless and until they are earned, the rights, preferences and privileges of the 2017 MYLTIP Units, 2018 MYLTIP Units and 2019 MYLTIP Units differ from other LTIP Units granted to employees (including the 2012 OPP Units, the 2013 MYLTIP Units, the 2014 MYLTIP Units, the 2015 MYLTIP Units and the 2016 MYLTIP Units, which have been earned). Therefore, unless specifically noted otherwise, all references to LTIP Units exclude the 2017 MYLTIP Units, 2018 MYLTIP Units and 2019 MYLTIP Units. LTIP Units (including the earned 2012 OPP Units, the 2013 MYLTIP Units, the 2014 MYLTIP Units, the 2015 MYLTIP Units and 2016 MYLTIP Units), whether vested or not, will receive the same quarterly per unit distributions as OP Units, which equal per share dividends on Common Stock (See Notes 8, 9 and 11).

At September 30, 2019, there was one series of Preferred Units outstanding (i.e., Series B Preferred Units). The Series B Preferred Units were issued to Boston Properties, Inc. on March 27, 2013 in connection with the issuance of 80,000 shares (8,000,000 depositary shares each representing 1/100th of a share) of 5.25% Series B Cumulative Redeemable Preferred Stock (the “Series B Preferred Stock”). Boston Properties, Inc. contributed the net proceeds from the offering to Boston Properties Limited Partnership in exchange for 80,000 Series B Preferred Units having terms and preferences generally mirroring those of the Series B Preferred Stock (See Note 9).

Properties

At September 30, 2019, the Company owned or had interests in a portfolio of 196 commercial real estate properties (the “Properties”) aggregating approximately 51.9 million net rentable square feet of primarily Class A office properties, including thirteen properties under construction/redevelopment totaling approximately 6.3 million net rentable square feet. At September 30, 2019, the Properties consisted of:


•	177 office properties (including eleven properties under construction/redevelopment);


•	twelve retail properties;


•	six residential properties (including two properties under construction); and


•	one hotel.

The Company considers Class A office properties to be well-located buildings that are professionally managed and maintained, attract high-quality tenants and command upper-tier rental rates, and that are modern structures or have been modernized to compete with newer buildings.

Basis Of Presentation And Summary Of Significant Accounting Policies

9 Months Ended

Sep. 30, 2019

Accounting Policies [Abstract]

Basis Of Presentation And Summary Of Significant Accounting Policies

2. Basis of Presentation and Summary of Significant Accounting Policies

Boston Properties, Inc. does not have any other significant assets, liabilities or operations, other than its investment in Boston Properties Limited Partnership, nor does it have employees of its own. Boston Properties Limited Partnership, not Boston Properties, Inc., generally executes all significant business relationships other than transactions involving securities of Boston Properties, Inc. All majority-owned subsidiaries and joint ventures over which the Company has financial and operating control and variable interest entities (“VIEs”) in which the Company has determined it is the primary beneficiary are included in the consolidated financial statements. All significant intercompany balances and transactions have been eliminated in consolidation. The Company accounts for all other unconsolidated joint ventures using the equity method of accounting. Accordingly, the Company’s share of the earnings of these joint ventures and companies is included in consolidated net income.

The accompanying interim financial statements are unaudited; however, the financial statements have been prepared in accordance with generally accepted accounting principles (“GAAP”) for interim financial information and in conjunction with the rules and regulations of the Securities and Exchange Commission. Accordingly, they do not include all of the disclosures required by GAAP for complete financial statements. In the opinion of management, all adjustments (consisting solely of normal recurring matters) necessary for a fair statement of the financial statements for these interim periods have been included. The results of operations for the interim periods are not necessarily indicative of the results to be obtained for other interim periods or for the full fiscal year. The year-end consolidated balance sheet data was derived from audited financial statements, but does not include all disclosure required by GAAP. These financial statements should be read in conjunction with the Company’s financial statements and notes thereto contained in the Company’s Annual Report in the Company’s Form 10-K for its fiscal year ended December 31, 2018.

Fair Value of Financial Instruments

The Company follows the authoritative guidance for fair value measurements when valuing its financial instruments for disclosure purposes. Boston Properties Limited Partnership determines the fair value of its unsecured senior notes using market prices. The inputs used in determining the fair value of Boston Properties Limited Partnership’s unsecured senior notes is categorized at a Level 1 basis (as defined in Accounting Standards Codification (“ASC”) 820 “Fair Value Measurements and Disclosures” (“ASC 820”)) due to the fact that it uses quoted market rates to value these instruments. However, the inputs used in determining the fair value could be categorized at a Level 2 basis (as defined in ASC 820) if trading volumes are low. The Company determines the fair value of its related party note receivable, note receivable and mortgage notes payable using discounted cash flow analysis by discounting the spread between the future contractual interest payments and hypothetical future interest payments on note receivables / mortgage debt based on current market rates for similar securities. In determining the current market rates, the Company adds its estimates of market spreads to the quoted yields on federal government treasury securities with similar maturity dates to its debt. The inputs used in determining the fair value of the Company’s related party note receivable, note receivable, and mortgage notes payable are categorized at a Level 3 basis (as defined in ASC 820) due to the fact that the Company considers the rates used in the valuation techniques to be unobservable inputs. To the extent that there are outstanding borrowings under the unsecured line of credit or unsecured term loan, the Company utilizes a discounted cash flow methodology in order to estimate the fair value. To the extent that credit spreads have changed since the origination, the net present value of the difference between future contractual interest payments and future interest payments based on the Company’s estimate of a current market rate would represent the difference between the book value and the fair value. The Company’s estimate of a current market rate is based upon the rate, considering current market conditions and Boston Properties Limited Partnership’s specific credit profile, at which it estimates it could obtain similar borrowings. To the extent there are outstanding borrowings, this current market rate is estimated and therefore would be primarily based upon a Level 3 input.

Because the Company’s valuations of its financial instruments are based on these types of estimates, the actual fair values of its financial instruments may differ materially from those estimates. In addition, the Company’s estimated fair values for these instruments as of the end of the applicable reporting period are not projections of nor necessarily indicative of estimated or actual fair values in future reporting periods. The following table presents the aggregate carrying value of the Company’s related party note receivable, note receivable, mortgage notes payable, net, unsecured senior notes, net, unsecured line of credit and unsecured term loan, net and the Company’s corresponding estimate of fair value as of September 30, 2019 and December 31, 2018 (in thousands):



	September 30, 2019				December 31, 2018
	Carrying Amount		Estimated Fair Value		Carrying Amount		Estimated Fair Value
Related party note receivable	$	80,000	$	81,337	$	80,000	$	80,000
Note receivable	19,844		18,507		19,468		19,468
	$	99,844	$	99,844	$	99,468	$	99,468

Mortgage notes payable, net	$	2,952,006	$	3,052,922	$	2,964,572	$	2,903,925
Unsecured senior notes, net	8,387,913		8,848,468		7,544,697		7,469,338
Unsecured line of credit	—		—		—		—
Unsecured term loan, net	498,819		500,618		498,488		500,783
Total	$	11,838,738	$	12,402,008	$	11,007,757	$	10,874,046

Variable Interest Entities (VIEs)

Consolidated VIEs are those for which the Company is considered to be the primary beneficiary of a VIE. The primary beneficiary is the entity that has a controlling financial interest in the VIE, which is defined by the entity having both of the following characteristics: (1) the power to direct the activities that, when taken together, most significantly impact the VIE’s performance and (2) the obligation to absorb losses or the right to receive the returns from the VIE that could potentially be significant to the VIE. The Company has determined that it is the primary beneficiary for six of the eight entities that are VIEs.

Consolidated Variable Interest Entities

As of September 30, 2019, Boston Properties, Inc. has identified six consolidated VIEs, including Boston Properties Limited Partnership. Excluding Boston Properties Limited Partnership, the VIEs consisted of the following five in-service properties: 767 Fifth Avenue (the General Motors Building), Times Square Tower, 601 Lexington Avenue, Atlantic Wharf Office Building and 100 Federal Street.

The Company consolidates these VIEs because it is the primary beneficiary. The third parties’ interests in these consolidated entities (i.e., excluding Boston Properties Limited Partnership’s interest) are reflected as noncontrolling interest in property partnerships in the accompanying Consolidated Financial Statements (See Note 8).

In addition, Boston Properties, Inc.’s only significant asset is its investment in Boston Properties Limited Partnership and, consequently, substantially all of Boston Properties, Inc.’s assets and liabilities are the assets and liabilities of Boston Properties Limited Partnership.

Variable Interest Entities Not Consolidated

The Company has determined that Platform 16 Holdings LP and the landlord entity for its Platform 16 ground lease are VIEs. The Company does not consolidate these entities as the Company does not have the power to direct the activities that, when taken together, most significantly impact the VIE’s performance and, therefore, the Company is not considered to be the primary beneficiary.

Out-of-Period Adjustment

During the three months ended September 30, 2019, the Company recorded a change in the balance sheet classification of deferred stock units held by non-employee directors of Boston Properties, Inc. that are outstanding under Boston Properties, Inc.’s 1997 and 2012 Stock Option and Incentive Plans (the “Plans”). The reclassification resulted from a modification to the terms of the non-employee director compensation program to provide, subject to certain conditions, the non-employee directors holding these units with the ability to elect, following cessation of their service on the Company’s Board of Directors, to diversify their investment elections into non-employer securities, which will ultimately be settled in cash. The modification required a change to the classification of these deferred stock units from permanent equity to temporary equity on the Consolidated Balance Sheets of Boston Properties, Inc. and Boston Properties Limited Partnership within Redeemable Deferred Stock Units. During the three months ended September 30, 2019, the Company recorded a change in the balance sheet classification of certain deferred stock units outstanding to correct the approximately $7.9 million overstatement of each of Additional Paid-in Capital of Boston Properties, Inc. and Partners’ Capital of Boston Properties Limited Partnership, the approximately $7.3 million understatement of each of Redeemable Deferred Stock Units of Boston Properties, Inc. and Boston Properties Limited Partnership, and the approximately $0.6 million understatement of each of Accounts Payable and Accrued Expenses of Boston Properties, Inc. and Boston Properties Limited Partnership in periods prior to September 30, 2019. Because this adjustment was not material to the prior periods’ consolidated financial statements and the impact of recording the adjustment in the three months ended September 30, 2019 was not material to Boston Properties, Inc.’s or Boston Properties Limited Partnership’s consolidated financial statements, the Company recorded the related adjustment during the three months ended September 30, 2019. The out-of-period adjustment was identified and recorded during the third quarter of 2019.

New Accounting Pronouncements

New Accounting Pronouncements Adopted

Leases

On January 1, 2019, the Company adopted Accounting Standards Update (“ASU”) 2016-02, “Leases (Topic 842)” (“ASU 2016-02” or “Topic 842”). For information pertaining to the Company’s adoption and disclosures with respect to leases, see Note 4.

New Accounting Pronouncements Issued but not yet Adopted

Financial Instruments - Credit Losses

In June 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” (“ASU 2016-13”). ASU 2016-13 is intended to provide financial statement users with more decision-useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date by replacing the current incurred loss impairment methodology with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. In November 2018, the FASB issued ASU 2018-19, “Codification Improvements to Topic 326, Financial Instruments - Credit Losses” (“ASU 2018-19”). ASU 2018-19 clarifies that receivables arising from operating leases are not within the scope of Accounting Standards Codification (“ASC”) 326-20, “Financial Instruments - Credit Losses - Measured at Amortized Cost,” which addresses financial assets measured at amortized cost basis, including net investments in leases arising from sales-type and direct financing leases. Instead, impairment of receivables arising from operating leases should be accounted for in accordance with ASC 842, “Leases” (“ASC 842”). ASU 2016-13 and ASU 2018-19 are effective for the Company for reporting periods beginning after December 15, 2019, with early adoption permitted. The Company will adopt ASU 2016-13 and ASU 2018-19 effective January 1, 2020 using the modified retrospective approach, which is expected to result in the Company recognizing on January 1, 2020 the cumulative effect of adopting ASU 2016-13 and ASU 2018-19 to certain of its financial instruments outstanding on January 1, 2020. The Company expects that (1) certain of its accounts receivable, except for amounts arising from operating leases accounted for under ASC 842, (2) its related party note receivable, (3) its note receivable and (4) certain of its financial guarantees may be impacted by the adoption of ASU 2016-13 and ASU 2018-19.

Real Estate

9 Months Ended

Sep. 30, 2019

Real Estate [Abstract]

Real Estate

3. Real Estate

Boston Properties, Inc.

Real estate consisted of the following at September 30, 2019 and December 31, 2018 (in thousands):



	September 30, 2019			December 31, 2018
Land	$	5,087,029		$	5,072,568
Right of use assets - finance leases	237,394			—
Right of use assets - operating leases	149,231			—
Land held for future development (1)	246,972			200,498
Buildings and improvements	13,396,648			13,356,751
Tenant improvements	2,559,907			2,396,932
Furniture, fixtures and equipment	44,908			44,351
Construction in progress	953,336			578,796
Total	22,675,425			21,649,896
Less: Accumulated depreciation	(5,164,353		)	(4,897,777		)
	$	17,511,072		$	16,752,119

_______________


(1)	Includes pre-development costs.

Boston Properties Limited Partnership

Real estate consisted of the following at September 30, 2019 and December 31, 2018 (in thousands):



	September 30, 2019			December 31, 2018
Land	$	4,986,576		$	4,971,475
Right of use assets - finance leases	237,394			—
Right of use assets - operating leases	149,231			—
Land held for future development (1)	246,972			200,498
Buildings and improvements	13,101,302			13,059,488
Tenant improvements	2,559,907			2,396,932
Furniture, fixtures and equipment	44,908			44,351
Construction in progress	953,336			578,796
Total	22,279,626			21,251,540
Less: Accumulated depreciation	(5,061,727		)	(4,800,475		)
	$	17,217,899		$	16,451,065

_______________


(1)	Includes pre-development costs.

Developments/Redevelopments

On May 9, 2019, the Company entered into a 15-year lease with Google, LLC for approximately 379,000 net rentable square feet of Class A office space in a build-to-suit development project located at the Company’s 325 Main Street property at Kendall Center in Cambridge, Massachusetts. 325 Main Street currently consists of an approximately 115,000 net rentable square foot Class A office property that will be demolished and developed into an approximately 420,000 net rentable square foot Class A office property, including approximately 41,000 net rentable square feet of retail space. On May 9, 2019, the Company commenced development of the project. Boston Properties, Inc. and Boston Properties Limited Partnership recognized approximately $9.9 million and $9.5 million, respectively, of depreciation expense associated with the acceleration of depreciation on the assets being removed from service and demolished as part of the redevelopment of the property.

On June 1, 2019, the Company partially placed in-service 20 CityPoint, a Class A office project with approximately 211,000 net rentable square feet located in Waltham, Massachusetts.

On September 30, 2019, the Company commenced the redevelopment of 200 West Street, a Class A office project with approximately 261,000 net rentable square feet located in Waltham, Massachusetts. The redevelopment is a conversion of a 126,000 square foot portion of the property to laboratory space.

Ground Leases

On January 24, 2019, the ground lessor under the Company’s 65-year ground lease for land totaling approximately 5.6 acres at Platform 16 located in San Jose, California made available for lease to the Company the remaining land parcels. As a result, the Company recognized the remaining portion of the right of use finance lease asset and finance lease liability. During 2018, the Company executed the ground lease. However, at the inception of the ground lease only a portion of the land was available for lease from the lessor, resulting in the Company recognizing only a portion of the ground lease. In the aggregate, the land will support the development of approximately 1.1 million square feet of commercial office space. The ground lease provides the Company with the right to purchase all of the land during a 12-month period commencing February 1, 2020 at a purchase price of approximately $134.8 million. The Company is reasonably certain it will exercise the option to purchase the land and as a result, the Company has concluded that the lease should be accounted for as a finance lease. As a result, the Company recorded an approximately $122.6 million right of use asset - finance lease and a lease liability - finance lease on the Company’s Consolidated Balance Sheets reflecting the remaining land parcels made available for lease to the Company. Finance lease assets and liabilities are accounted for at the lower of fair market value or the present value of future lease payments. For land leases classified as finance leases because of a purchase option that the Company views as an economic incentive, the Company follows its existing policy and does not depreciate land because it is assumed to have an indefinite life. See also Dispositions below and Note 5.

As of January 24, 2019, the lease payments from the finance lease related to the remaining parcels made available for lease to the Company were as follows (in thousands):



Period from January 24, 2019 through December 31, 2019	$	17,918
2020	109,460
Total expected minimum lease payments	127,378
Interest portion	(4,815		)
Present value of expected net lease payments	$	122,563

On July 16, 2019, the Company executed a 75-year ground lease with The George Washington University for land parcels at 2100 Pennsylvania Avenue located in Washington, DC and commenced development of an approximately 470,000 net rentable square foot Class A office property pursuant to a development agreement that the Company entered into with The George Washington University in 2016. The development agreement provided for the execution of the ground lease upon completion of the entitlement process and relocation of existing tenants. Also in 2016, the Company made a deposit of $15.0 million that, upon execution of the ground lease, is being credited against ground rent payable under the ground lease. The present value of the lease payments exceeds substantially all of the fair value of the underlying asset and as a result, the Company has concluded that the ground lease should be accounted for as a finance lease. As a result, the Company recorded an approximately $185.1 million right of use asset - finance lease and an approximately $165.0 million lease liability - finance lease on the Company’s Consolidated Balance Sheets. The difference between the right of use asset - finance lease and lease liability - finance lease is the $15.0 million deposit that was made in 2016 and approximately $5.1 million of initial direct costs. Although the finance lease is for land only, as this was not classified as a finance lease because of a purchase option, the right of use asset will be amortized over the shorter of the useful life of the asset or the lease term. As land is assumed to have an indefinite life, the right of use asset - finance lease will be amortized on a straight-line basis over the 75-year term. In 2017, the Company entered into a 16-year lease with a tenant for approximately 300,000 net rentable square feet of space at the property.

As of July 16, 2019, the lease payments from the finance lease were as follows (in thousands):



Period from July 16, 2019 through December 31, 2019	$	—
2020	—
2021	3,863
2022	8,576
2023	8,669
Thereafter	1,358,518
Total expected minimum lease payments	1,379,626
Interest portion	(1,214,649		)
Present value of expected net lease payments	$	164,977

Acquisitions

On January 10, 2019, the Company acquired land parcels at its Carnegie Center property located in Princeton, New Jersey for a gross purchase price of approximately $51.5 million, which includes an aggregate of approximately $8.6 million of additional amounts that are payable in the future to the seller upon the development or sale of each of the parcels. The land parcels could support approximately 1.7 million square feet of development.

On August 27, 2019, the Company acquired 880 and 890 Winter Street located in Waltham, Massachusetts for a gross purchase price of approximately $106.0 million in cash. 880 and 890 Winter Street consists of two Class A office properties aggregating approximately 392,000 net rentable square feet. The following table summarizes the allocation of the purchase price, including transaction costs, of 880 and 890 Winter Street at the date of acquisition (in thousands):



Land	$	31,376
Building and improvements	57,922
Tenant improvements	6,024
In-place lease intangibles	11,494
Above-market lease intangibles	246
Below-market lease intangibles	(1,092		)
Net assets acquired	$	105,970

The following table summarizes the estimated annual amortization of the acquired in-place lease intangibles, the acquired above-market lease intangibles and the acquired below-market lease intangibles for 880 and 890 Winter Street for the remainder of 2019 and each of the next five succeeding fiscal years (in thousands):



	Acquired In-Place Lease Intangibles		Acquired Above-Market Lease Intangibles		Acquired Below- Market Lease Intangibles
Period from August 27, 2019 through December 31, 2019	$	1,801	$	28	$	(226	)
2020	4,485		80		(599		)
2021	2,391		80		(237		)
2022	1,121		43		(30		)
2023	179		15		—
2024	60		—		—

880 and 890 Winter Street contributed approximately $1.3 million of revenue and approximately ($0.2) million of earnings to the Company for the period from August 27, 2019 through September 30, 2019.

Dispositions

On January 24, 2019, the Company completed the sale of its 2600 Tower Oaks Boulevard property located in Rockville, Maryland for a gross sale price of approximately $22.7 million. Net cash proceeds totaled approximately $21.4 million, resulting in a loss on sale of real estate totaling approximately $0.6 million. The Company recognized an impairment loss totaling approximately $3.1 million for Boston Properties, Inc. and approximately $1.5 million for Boston Properties Limited Partnership during the year ended December 31, 2018. 2600 Tower Oaks Boulevard is an approximately 179,000 net rentable square foot Class A office property. 2600 Tower Oaks contributed approximately $(0.2) million of net loss to the Company for the period from January 1, 2019 through January 23, 2019 and contributed approximately $(0.2) million and $(0.5) million of net loss to the Company for the three and nine months ended September 30, 2018, respectively.

At March 31, 2019, the Company evaluated the expected hold period of its One Tower Center property and, based on a shorter-than-expected hold period, the Company reduced the carrying value of the property to its estimated fair value at March 31, 2019 and recognized an impairment loss totaling approximately $24.0 million for Boston Properties, Inc. and approximately $22.3 million for Boston Properties Limited Partnership. The Company’s estimated fair value was based on a pending offer from a third party to acquire the property and the subsequent execution of a purchase and sale agreement on April 18, 2019 for a gross sale price of $38.0 million. On June 3, 2019, the Company completed the sale of the property. Net cash proceeds totaled approximately $36.6 million, resulting in a loss on sale of real estate totaling approximately $0.8 million. One Tower Center is an approximately 410,000 net rentable square foot Class A office property located in East Brunswick, New Jersey. One Tower Center contributed approximately $(0.1) million and $(0.9) million of net loss to the Company for the period from April 1, 2019 through June 2, 2019 and the period from January 1, 2019 through June 2, 2019, respectively, and contributed approximately $(0.7) million and $(2.0) million of net loss to the Company for the three and nine months ended September 30, 2018, respectively.

On June 28, 2019, the Company completed the sale of its 164 Lexington Road property located in Billerica, Massachusetts for a gross sale price of $4.0 million. Net cash proceeds totaled approximately $3.8 million, resulting in a gain on sale of real estate totaling approximately $2.5 million for Boston Properties, Inc. and approximately $2.6 million for Boston Properties Limited Partnership. 164 Lexington Road is an approximately 64,000 net rentable square foot Class A office property. 164 Lexington Road contributed approximately $(0.1) million and $(0.1) million of net loss to the Company for the period from April 1, 2019 through June 27, 2019 and the period from January 1, 2019 through June 27, 2019, respectively, and contributed approximately $(0.05) million and $(0.2) million of net loss to the Company for the three and nine months ended September 30, 2018, respectively.

On September 20, 2019, the Company entered into a joint venture with Canada Pension Plan Investment Board (“CPPIB”) to develop Platform 16 located in San Jose, California. Platform 16 consists of a 65-year ground lease for land totaling approximately 5.6 acres that will support the development of approximately 1.1 million square feet of commercial office space. During 2018, the Company entered into the ground lease, which provides for the right to purchase all of the land during a 12-month period commencing February 1, 2020 at a purchase price of approximately $134.8 million. The Company contributed the ground lease interest and improvements totaling approximately $28.2 million for its initial 55% interest in the joint venture. CPPIB contributed cash totaling approximately $23.1 million for its initial 45% interest in the joint venture. Upon the CPPIB contribution, the Company ceased accounting for the joint venture entity on a consolidated basis and is accounting for the joint venture entity on an unconsolidated basis using the equity method of accounting as it has reduced its ownership interest in the joint venture entity and no longer has a controlling financial or operating interest in the joint venture entity (See Note 5). The Company did not recognize a gain on the retained or sold interest in the real estate contributed to the joint venture, as the fair value of the real estate approximated its carrying value.

Leases

9 Months Ended

Sep. 30, 2019

Leases [Abstract]

Leases of Lessee Disclosure

4. Leases

General Adoption

In February 2016, the FASB issued ASU 2016-02, which sets out the principles for the recognition, measurement, presentation and disclosure of leases for both parties to a contract (i.e., lessees and lessors). ASU 2016-02 requires lessees to apply a dual approach, classifying leases as either finance or operating leases based on the principle of whether or not the lease for accounting purposes is effectively a financed purchase of the leased asset by the lessee. This classification will determine whether the lease expense is recognized based on an effective interest method or on a straight-line basis over the term of the lease. A lessee is also required to record a right-of-use asset and a lease liability for all leases with a term of greater than 12 months regardless of their

classification. Leases with a term of 12 months or less will be accounted for similar to the prior guidance in ASC 840 -“Leases” (“Topic 840”). ASU 2016-02 requires lessors to account for leases using an approach that is substantially equivalent to Topic 840 for sales-type leases, direct financing leases and operating leases. ASU 2016-02 supersedes previous leasing standards.

On July 30, 2018, the FASB issued ASU 2018-11, “Leases (Topic 842): Targeted Improvements” (“ASU 2018-11”), that (1) simplifies transition requirements for both lessees and lessors by adding an option that permits an organization to apply the transition provisions of the new standard at its adoption date instead of at the earliest comparative period presented in its financial statements and (2) allows lessors to elect, as a practical expedient, by class of underlying asset, to not separate nonlease components from the associated lease component and, instead, to account for those components as a single component if the nonlease components otherwise would be accounted for under the revenue guidance (ASU 2014-09, “Revenue from Contracts with Customers (Topic 606) (“ASC 606”)) that was adopted on January 1, 2018, and both of the following are met:

(1) the timing and pattern of transfer of the nonlease component(s) and associated lease components are the same; and

(2) the lease component, if accounted for separately, would be classified as an operating lease.

If the nonlease component or components associated with the lease component are the predominant component of the combined component, an entity is required to account for the combined component in accordance with ASC 606.

The Company adopted ASU 2016-02 and ASU 2018-11 effective January 1, 2019. For purposes of transition, the Company elected the practical expedient package, which has been applied consistently to all of its leases, but did not elect the hindsight practical expedient. The practical expedient package did not require the Company to reassess the following: (i) whether an expired or existing contract meets the definition of a lease; (ii) the lease classification at the adoption date for existing leases; and (iii) whether costs previously capitalized as initial direct costs would continue to be amortized. This allows the Company to continue to account for its ground leases as operating leases. However, as of January 1, 2019, any new or modified ground leases may be classified as financing leases unless they meet certain conditions. The Company also elected to apply the transition provisions as of the adoption date, January 1, 2019, and not change its comparative statements. The Company recorded an adjustment to the opening balance of retained earnings related to initial direct costs that, as of January 1, 2019, had not started to amortize and are no longer allowed to be capitalized in accordance with ASU 2016-02, totaling approximately $3.9 million to Dividends in Excess of Earnings of Boston Properties, Inc. and Partners’ Capital of Boston Properties Limited Partnership, approximately $0.4 million to Noncontrolling interests - Common Units of Boston Properties, Inc. and Noncontrolling Interest - Redeemable Partnership Units of Boston Properties Limited Partnership and $70,000 to Noncontrolling Interests - Property Partnerships of Boston Properties, Inc. and Noncontrolling Interests in Property Partnerships of Boston Properties Limited Partnership on the corresponding Consolidated Balance Sheets.

The Company made the policy election, when it is the lessee, to not apply the revenue recognition requirements of Topic 842 to short-term leases. This policy election is made by class of underlying assets and as described below, the Company considers real estate to be a class of underlying assets, and will not be further delineating it into specific uses of the real estate asset as the risk profiles are similar in nature. The Company will recognize the lease payments in net income on a straight-line basis over the lease term.

Lease payments from operating leases are recognized on a straight-line basis over the term of the leases. The cumulative difference between lease revenue recognized under this method and the contractual lease payment terms is recorded as deferred rent receivable on our consolidated balance sheets. The Company reviews its trade accounts receivable, including its straight-line rent receivable, related to base rents, straight-line rent, expense reimbursements and other revenues for collectability. The Company analyzes its accounts receivable, customer credit worthiness and current economic trends when evaluating the adequacy of the collectability of the lessee’s total accounts receivable balance on a lease-by-lease basis. In addition, tenants in bankruptcy are analyzed and considerations are made in connection with the expected recovery of pre-petition and post-petition claims. If a lessee’s accounts receivable balance is considered uncollectible the Company will write-off the receivable balances associated with the lease to Lease revenue and cease to recognize lease income, including straight-line rent unless cash is received. If the Company subsequently determines that it is probable it will collect substantially all the remaining lessee’s lease payments under the lease term, the Company will then reinstate the straight-line balance adjusting for the amount related to the period when the lease payments were considered not probable. The

Company’s reported net earnings are directly affected by management’s estimate of the collectability of its trade accounts receivable.

In January 2018, the FASB issued ASU 2018-01, “Leases (Topic 842): Land Easement Practical Expedient for Transition to Topic 842” (“ASU 2018-01”), which provides an optional transition practical expedient to not evaluate, under Topic 842, existing or expired land easements that were not previously accounted for as leases under the leases guidance in Topic 840. An entity that elects this practical expedient should evaluate new or modified land easements under Topic 842 beginning at the date that the entity adopts Topic 842. An entity that does not elect this practical expedient should evaluate all existing or expired land easements in connection with the adoption of the new lease requirements in Topic 842 to assess whether they meet the definition of a lease. The effective date and transition requirements for ASU 2018-01 are the same as the effective date and transition requirements in ASU 2016-02. The Company adopted ASU 2018-01 on January 1, 2019.

Lessee

For leases in which the Company is the lessee (generally ground leases), on January 1, 2019, the Company recognized a right-of-use asset and a lease liability of approximately $151.8 million and $199.3 million, respectively. The lease liability was equal to the present value of the minimum lease payments in accordance with Topic ASC 840. In addition, the Company did not know the rate implicit in any of its ground leases that were classified as operating leases, and accordingly used the Company’s incremental borrowing rate (“IBR”) to determine the net present value of the minimum lease payments.

In order to determine the IBR, the Company utilized a market-based approach to estimate the incremental borrowing rate for each individual lease. The approach required significant judgment. Therefore, the Company utilized different data sets to estimate base IBRs via an analysis of the following weighted-components:


•	The interpolated rates from yields on outstanding U.S. Treasury issuances for up to 30 years and for years 31 and beyond, longer-term publicly traded educational institution debt issued by high credit quality educational institutions with maturity dates up to 2116,


•	Observable mortgage rates spread over U.S. Treasury issuances, and


•	Unlevered property yields and discount rates.

The Company then applied adjustments to account for considerations related to term and interpolated the IBR.

The Company has four non-cancelable ground lease obligations, which were classified as operating leases, with various initial term expiration dates through 2114. The Company recognizes ground rent expense on a straight-line basis over the term of the respective ground lease agreements. None of the amounts disclosed below for these ground leases contain variable payments, extension options or residual value guarantees. One of the ground leases does have an extension option. However, lease payments for this ground lease are based on fair market value and as such have not been included in the analysis below.

The Company has four finance lease obligations with various initial term expiration dates through 2094, see Notes 3 and 5.

The following table provides lease cost information for the Company’s operating and finance leases for the three and nine months ended September 30, 2019 (in thousands):



	Three months ended September 30, 2019		Nine months ended September 30, 2019
Lease costs
Operating lease costs	$	3,637	$	10,970
Finance lease costs
Amortization of right of use asset (1)	$	12	$	14
Interest on lease liabilities (2)	$	12	$	36

_______________


(1)	The finance leases relate to either land, buildings or assets that remain in development. For land leases classified as finance leases because of a purchase option that the Company views as an economic incentive, the Company follows its existing policy and does not depreciate land because it is assumed to

have an indefinite life. For all other finance leases, the Company would amortize the right of use asset over the shorter of the useful life of the asset or the lease term. If the finance lease relates to a property under development, the amortization of the right of use asset may be eligible for capitalization. For assets under development, depreciation may commence once the asset is placed in-service and depreciation would be recognized in accordance with the Company’s policy.


(2)	Three of the finance leases relate to assets under development and as such, the entire interest amount was capitalized.

The following table provides other quantitative information for the Company’s operating and finance leases as of September 30, 2019:



	September 30, 2019
Other information
Weighted-average remaining lease term (in years)
Operating leases	51
Finance leases	72
Weighted-average discount rate
Operating leases	5.7	%
Finance leases	6.2	%

The following table provides a maturity analysis for the Company’s future contractual minimum lease payments to be made by the Company as of December 31, 2018, under non-cancelable ground leases which expire on various dates through 2114:



Years Ending December 31,	(in thousands)
2019	$	11,425
2020	18,425
2021	25,310
2022	8,894
2023	9,084
Thereafter	567,232

The following table provides a maturity analysis for the Company's future minimum lease payments, as of December 31, 2018, related to the four capital leases, through 2036:



Years Ending December 31,	(in thousands)
2019	$	1,441
2020	12,682
2021	2,123
2022	1,253
2023	944
Thereafter	73,241
Total expected minimum lease payments	91,684
Interest portion	(27,497		)
Present value of expected net minimum lease payments	$	64,187

The following table provides a maturity analysis for the Company’s lease liabilities related to its operating and finance leases as of September 30, 2019 (in thousands):



	Operating			Finance
October 1, 2019 - December 31, 2019	$	2,426		$	150
2020	10,050			907
2021	24,953			5,958
2022	18,041			10,208
2023	10,345			9,708
Thereafter (1)	567,232			1,431,760
Total lease payments	633,047			1,458,691
Less: interest portion	(433,292		)	(1,237,662		)
Present value of lease payments	$	199,755		$	221,029

_______________


(1)	Finance lease payments in 2024 include approximately $38.7 million related to a purchase option that the Company is reasonably certain it will exercise.

Lessor, Operating Leases

Lessor

The Company leases primarily Class A office, retail and residential space to tenants. These leases may contain extension and termination options that are predominately at the sole discretion of the tenant, provided certain conditions are satisfied. In a few instances, the leases also contain purchase options, which would be exercisable at fair market value. Also, certain of the Company’s leases include rental payments that are based on a percentage of the tenant sales in excess of contractual amounts.

ASU 2018-11 provides lessors a practical expedient to not separate nonlease components from the associated lease component if certain criteria stated above are met for each class of underlying assets. The guidance in Topic 842 defines “underlying asset” as “an asset that is the subject of a lease for which a right to use that asset has been conveyed to a lessee. The underlying asset could be a physically distinct portion of a single asset.” Based on the above guidance, the Company considers real estate assets as a class of underlying assets and will not be further delineating it into specific uses of the real estate asset as the risk profiles are similar in nature.

Lease components are elements of an arrangement that provide the customer with the right to use an identified asset. Nonlease components are distinct elements of a contract that are not related to securing the use of the leased asset and revenue is recognized in accordance with ASC 606. The Company considers common area maintenance (CAM) and service income associated with tenant work orders to be nonlease components because they represent delivery of a separate service but are not considered a cost of securing the identified asset. In the case of the Company’s business, the identified asset would be the leased real estate (office, retail or residential).

The Company assessed and concluded that the timing and pattern of transfer for nonlease components and the associated lease component are the same. The Company determined that the predominant component was the lease component and as such its leases will continue to qualify as operating leases and the Company has made a policy election to account for and present the lease component and the nonlease component as a single component in the revenue section of the Consolidated Statements of Operations labeled Lease. Prior to the adoption of Topic 842, nonlease components had been included within Recoveries from Tenants Revenue, Parking and Other Revenue and Development and Management Services Revenue on the Company’s Consolidated Statements of Operations.

In addition, under ASU 2016-02, lessors will only capitalize incremental direct leasing costs. As a result, starting January 1, 2019, the Company no longer capitalizes non-incremental legal costs and internal leasing wages. These costs are expensed as incurred. The expensing of these items is included within General and Administrative Expense on the Consolidated Statements of Operations.

The following table summarizes the components of lease revenue recognized during the three and nine months ended September 30, 2019 included within the Company’s Consolidated Statements of Operations (in thousands):



Lease Revenue	Three months ended September 30, 2019		Nine months ended September 30, 2019
Fixed contractual payments	$	566,294	$	1,678,100
Variable lease payments	125,931		373,565
	$	692,225	$	2,051,665

The Company’s properties are leased to tenants under operating leases with initial term expiration dates ranging from 2019 to 2049.

The future contractual minimum lease payments to be received (excluding operating expense reimbursements) by the Company as of December 31, 2018, under non-cancelable operating leases which expire on various dates through 2049:



Years Ending December 31,	(in thousands)
2019	$	2,088,171
2020	2,106,963
2021	2,015,031
2022	1,838,699
2023	1,736,636
Thereafter	12,295,464

The future contractual lease payments to be received (excluding operating expense reimbursements) by the Company as of September 30, 2019, under non-cancelable operating leases which expire on various dates through 2049:



	(in thousands)
October 1, 2019 - December 31, 2019	$	530,470
2020	2,196,428
2021	2,177,016
2022	2,050,537
2023	1,980,918
Thereafter	15,447,131

Investments in Unconsolidated Joint Ventures

9 Months Ended

Sep. 30, 2019

Investments In Unconsolidated Joint Ventures [Abstract]

Investments In Unconsolidated Joint Ventures

5. Investments in Unconsolidated Joint Ventures

The investments in unconsolidated joint ventures consist of the following at September 30, 2019 and December 31, 2018:



		Nominal % Ownership			Carrying Value of Investment (1)
Entity	Properties	Nominal % Ownership			September 30, 2019			December 31, 2018
					(in thousands)
Square 407 Limited Partnership	Market Square North	50.0	%		$	(5,114	)	$	(6,424	)
BP/CRF Metropolitan Square, LLC	Metropolitan Square	20.0	%		5,726			2,644
901 New York, LLC	901 New York Avenue	25.0	%	(2)	(12,385		)	(13,640		)
WP Project Developer LLC	Wisconsin Place Land and Infrastructure	33.3	%	(3)	37,179			38,214
Annapolis Junction NFM LLC	Annapolis Junction	50.0	%	(4)	25,314			25,268
540 Madison Venture LLC	540 Madison Avenue	60.0	%	(5)	3,075			66,391
500 North Capitol Venture LLC	500 North Capitol Street, NW	30.0	%		(5,661		)	(5,026		)
501 K Street LLC	1001 6th Street	50.0	%	(6)	42,555			42,557
Podium Developer LLC	The Hub on Causeway - Podium	50.0	%		41,434			69,302
Residential Tower Developer LLC	The Hub on Causeway - Residential	50.0	%		48,491			47,505
Hotel Tower Developer LLC	The Hub on Causeway - Hotel Air Rights	50.0	%		3,917			3,022
Office Tower Developer LLC	100 Causeway Street	50.0	%		74,083			23,804
1265 Main Office JV LLC	1265 Main Street	50.0	%		3,932			3,918
BNY Tower Holdings LLC	Dock 72	50.0	%		94,700			82,520
CA-Colorado Center Limited Partnership	Colorado Center	50.0	%		250,213			253,495
7750 Wisconsin Avenue LLC	7750 Wisconsin Avenue	50.0	%		55,662			69,724
BP-M 3HB Venture LLC	3 Hudson Boulevard	25.0	%		54,037			46,993
SMBP Venture LP	Santa Monica Business Park	55.0	%		163,809			180,952
Platform 16 Holdings LP	Platform 16	55.0	%	(7)	29,128			—
					$	910,095		$	931,219

_______________


(1)	Investments with deficit balances aggregating approximately $23.2 million and $25.1 million at September 30, 2019 and December 31, 2018, respectively, have been reflected within Other Liabilities in the Company’s Consolidated Balance Sheets.


(2)	The Company’s economic ownership has increased based on the achievement of certain return thresholds.


(3)	The Company’s wholly-owned subsidiary that owns Wisconsin Place Office also owns a 33.3% interest in the joint venture entity that owns the land, parking garage and infrastructure of the project.


(4)	The joint venture owns three in-service buildings and two undeveloped land parcels.


(5)	The property was sold on June 27, 2019. As of September 30, 2019, the investment is comprised of undistributed cash. See note below for additional details.


(6)	Under the joint venture agreement for this land parcel, the partner will be entitled to up to two additional payments from the venture based on increases in total entitled square footage of the project above 520,000 square feet and achieving certain project returns at stabilization.


(7)	This entity is a VIE (See Note 2).

Certain of the Company’s unconsolidated joint venture agreements provide that, at certain specified times, each partner has the right to initiate a purchase or sale of its interest in the joint ventures. With limited exceptions, under these provisions, the Company is not compelled to purchase the interest of its outside joint venture partners. Under certain of the Company’s joint venture agreements, if certain return thresholds are achieved, the partners or the Company will be entitled to an additional promoted interest or payments.

The Company classifies distributions received from equity method investees within its consolidated statements of cash flows using the nature of the distribution approach, which classifies the distributions received on the basis of the nature of the activity or activities of the investee that generated the distribution as either a return on investment (classified as cash inflows from operating activities) or a return of investment (classified as cash inflows from investing activities).

The combined summarized balance sheets of the Company’s unconsolidated joint ventures are as follows:



	September 30, 2019		December 31, 2018
	(in thousands)
ASSETS
Real estate and development in process, net (1)	$	3,782,279	$	3,545,906
Other assets	498,040		543,512
Total assets	$	4,280,319	$	4,089,418
LIABILITIES AND MEMBERS’/PARTNERS’ EQUITY
Mortgage and notes payable, net	$	2,107,805	$	2,017,609
Other liabilities (2)	773,033		582,006
Members’/Partners’ equity	1,399,481		1,489,803
Total liabilities and members’/partners’ equity	$	4,280,319	$	4,089,418
Company’s share of equity	$	569,704	$	622,498
Basis differentials (3)	340,391		308,721
Carrying value of the Company’s investments in unconsolidated joint ventures (4)	$	910,095	$	931,219

_______________


(1)	At September 30, 2019, this amount includes right of use assets - finance leases and right of use assets - operating leases totaling approximately $383.9 million and $12.3 million, respectively.


(2)	At September 30, 2019, this amount includes lease liabilities - finance leases and lease liabilities - operating leases totaling approximately $511.7 million and $17.3 million, respectively.

(3)

This amount represents the aggregate difference between the Company’s historical cost basis and the basis reflected at the joint venture level, which is typically amortized over the life of the related assets and liabilities. Basis differentials result from impairments of investments, acquisitions through joint ventures with no change in control and upon the transfer of assets that were previously owned by the Company into a joint venture. In addition, certain acquisition, transaction and other costs may not be reflected in the net assets at the joint venture level. At September 30, 2019 and December 31, 2018, there was an aggregate basis differential of approximately $312.3 million and $316.7 million, respectively, between the carrying value of the Company’s investment in the joint venture that owns Colorado Center and the joint venture’s basis in the assets and liabilities, which differential (excluding land) shall be amortized over the remaining lives of the related assets and liabilities.


(4)	Investments with deficit balances aggregating approximately $23.2 million and $25.1 million at September 30, 2019 and December 31, 2018, respectively, have been reflected within Other Liabilities in the Company’s Consolidated Balance Sheets.

The combined summarized statements of operations of the Company’s unconsolidated joint ventures are as follows:



	Three months ended September 30,						Nine months ended September 30,
	2019			2018			2019			2018
	(in thousands)
Total revenue (1)	$	75,940		$	76,177		$	239,099		$	189,759
Expenses
Operating	28,839			29,522			89,472			75,239
Depreciation and amortization	23,477			44,993			76,941			74,245
Total expenses	52,316			74,515			166,413			149,484
Other income (expense)
Interest expense	(20,483		)	(19,861		)	(62,043		)	(48,993		)
Gain on sale of real estate (2)	(812		)	—			33,760			—
Net income (loss)	$	2,329		$	(18,199	)	$	44,403		$	(8,718	)

Company’s share of net income (loss)	$	392		$	(2,858	)	$	24,352		$	1,073
Basis differential (2) (3)	(1,041		)	(1,455		)	23,176			(4,156		)
Income (loss) from unconsolidated joint ventures	$	(649	)	$	(4,313	)	$	47,528		$	(3,083	)

_______________


(1)	Includes straight-line rent adjustments of approximately $5.3 million and $4.8 million for the three months ended September 30, 2019 and 2018, respectively, and $18.7 million and $9.8 million for the nine months ended September 30, 2019 and 2018, respectively.

(2)

Represents the total gain on sale of 540 Madison Avenue recognized by the joint venture, as described below. During 2008, the Company recognized an other-than-temporary impairment loss on its investment in the unconsolidated joint venture resulting in a basis differential between the carrying value of the Company’s investment in the joint venture and the joint venture’s basis in the assets and liabilities of the property. As a result of the historical basis difference, the Company recognized a gain on sale of real estate totaling approximately $47.3 million for the nine months ended September 30, 2019, which consists of its share of the gain on sale reported by the joint venture as well as an adjustment for the basis differential. The Company recognized a reduction to the gain on sale of real estate totaling approximately $0.5 million for the three months ended September 30, 2019. The gain on sale is included in Income (Loss) from Unconsolidated Joint Ventures in the Company’s Consolidated Statements of Operations.

(3)

Includes straight-line rent adjustments of approximately $0.5 million and $0.5 million for the three months ended September 30, 2019 and 2018, respectively, and $1.6 million and $1.9 million for the nine months ended September 30, 2019 and 2018, respectively. Also includes net above-/below-market rent adjustments of approximately $0.4 million and $0.4 million for the three months ended September 30, 2019 and 2018, respectively, and $1.3 million and $1.2 million for the nine months ended September 30, 2019 and 2018, respectively.

On January 24, 2019, a joint venture in which the Company has a 50% interest extended the loan collateralized by its Annapolis Junction Building Six property. At the time of the extension, the outstanding balance of the loan totaled approximately $13.0 million and was scheduled to mature on November 17, 2019, with a one-year extension option, subject to certain conditions. The extended loan has a total commitment amount of approximately $14.3 million, bears interest at a variable rate equal to LIBOR plus 2.00% per annum and matures on November 17, 2020. Annapolis Junction Building Six is a Class A office property with approximately 119,000 net rentable square feet located in Annapolis, Maryland.

On April 26, 2019, a joint venture in which the Company has a 50% interest obtained construction financing with a total commitment of $255.0 million collateralized by its 7750 Wisconsin Avenue development project located in Bethesda, Maryland. The construction financing bears interest at a variable rate equal to LIBOR plus 1.25% per annum and matures on April 26, 2023, with two, one-year extension options, subject to certain conditions. As of September 30, 2019, approximately $39.6 million has been drawn under the loan. 7750 Wisconsin Avenue is a 734,000 net rentable square foot build-to-suit Class A office project and below-grade parking garage.

On May 28, 2019, joint ventures in which the Company has a 50% interest and that own The Hub on Causeway - Podium and 100 Causeway Street development projects entered into an infrastructure development assistance agreement (the “IDAA”) with the Commonwealth of Massachusetts and the City of Boston. Per the IDAA, The Hub on Causeway - Podium development project would be reimbursed for certain costs of public infrastructure improvements using the proceeds of up to $30.0 million in aggregate principal amount of municipal bonds issued by the Commonwealth of Massachusetts. On September 16, 2019, the joint venture received the full reimbursement of costs for the public infrastructure improvements totaling approximately $28.8 million, which has been reflected as a reduction to the carrying value of the real estate of The Hub on Causeway - Podium property. The construction loan agreement for The Hub on Causeway - Podium was modified to require the joint venture to pay down the construction loan principal balance using the proceeds received from the reimbursement of costs of the public infrastructure improvements and on September 16, 2019, the joint venture that owns The Hub on Causeway - Podium development project paid down the construction loan principal balance in the amount of approximately $28.8 million. On June 15, 2019, the joint venture that owns The Hub on Causeway - Podium development project partially placed in-service The Hub on Causeway - Podium development project, an approximately 375,000 net rentable square foot project containing retail and office space located in Boston, Massachusetts.

On June 27, 2019, a joint venture in which the Company has a 60% interest completed the sale of 540 Madison Avenue in New York City for a gross sale price of approximately $310.3 million, including the assumption by the buyer of the mortgage loan collateralized by the property totaling $120.0 million. The mortgage loan bore interest at a variable rate equal to LIBOR plus 1.10% per annum and was scheduled to mature on June 5, 2023. Net cash proceeds totaled approximately $178.7 million, of which the Company’s share was approximately $107.1 million, after the payment of transaction costs. During 2008, the Company recognized an other-than-temporary impairment loss on its investment in the unconsolidated joint venture. As a result, the Company recognized a gain on sale of real estate totaling approximately $47.3 million, which is included in Income (Loss) from Unconsolidated Joint Ventures in the accompanying Consolidated Statements of Operations. 540 Madison Avenue is an approximately 284,000 net rentable square foot Class A office property.

On September 5, 2019, a joint venture in which the Company has a 50% interest obtained construction financing with a total commitment of $400.0 million collateralized by its 100 Causeway Street development project located in Boston, Massachusetts. The construction financing bears interest at a variable rate equal to LIBOR plus 1.50% per annum (LIBOR plus 1.375% per annum upon stabilization, as defined in the loan agreement) and matures on September 5, 2023, with two, one-year extension options, subject to certain conditions. As of September 30, 2019, approximately $47.7 million has been drawn under the loan. 100 Causeway Street is an approximately 632,000 net rentable square foot Class A office project.

On September 20, 2019, the Company entered into a joint venture with CPPIB to develop Platform 16 located in San Jose, California. Platform 16 consists of a 65-year ground lease for land totaling approximately 5.6 acres that will support the development of approximately 1.1 million square feet of commercial office space. The Company contributed the ground lease interest and improvements totaling approximately $28.2 million for its initial 55% interest in the joint venture (See Note 3). CPPIB contributed cash totaling approximately $23.1 million for its initial 45% interest in the joint venture. The Company will provide customary development, property management and leasing services to the joint venture.

Unsecured Senior Notes

9 Months Ended

Sep. 30, 2019

Debt Disclosure [Abstract]

Unsecured Senior Notes

6. Unsecured Senior Notes

The following summarizes the unsecured senior notes outstanding as of September 30, 2019 (dollars in thousands):



	Coupon/Stated Rate		Effective Rate(1)		Principal Amount			Maturity Date(2)
10 Year Unsecured Senior Notes	4.125	%	4.289	%	$	850,000		May 15, 2021
11 Year Unsecured Senior Notes	3.850	%	3.954	%	1,000,000			February 1, 2023
10.5 Year Unsecured Senior Notes	3.125	%	3.279	%	500,000			September 1, 2023
10.5 Year Unsecured Senior Notes	3.800	%	3.916	%	700,000			February 1, 2024
7 Year Unsecured Senior Notes	3.200	%	3.350	%	850,000			January 15, 2025
10 Year Unsecured Senior Notes	3.650	%	3.766	%	1,000,000			February 1, 2026
10 Year Unsecured Senior Notes	2.750	%	3.495	%	1,000,000			October 1, 2026
10 Year Unsecured Senior Notes	4.500	%	4.628	%	1,000,000			December 1, 2028
10 Year Unsecured Senior Notes	3.400	%	3.505	%	850,000			June 21, 2029
10.5 Year Unsecured Senior Notes	2.900	%	2.984	%	700,000			March 15, 2030
Total principal					8,450,000
Net unamortized discount					(18,232		)
Deferred financing costs, net					(43,855		)
Total					$	8,387,913

_______________


(1)	Yield on issuance date including the effects of discounts on the notes, settlements of interest rate contracts and the amortization of financing costs.


(2)	No principal amounts are due prior to maturity.

On June 21, 2019, Boston Properties Limited Partnership completed a public offering of $850.0 million in aggregate principal amount of its 3.400% unsecured senior notes due 2029. The notes were priced at 99.815% of the principal amount to yield an effective rate (including financing fees) of approximately 3.505% per annum to maturity. The notes will mature on June 21, 2029, unless earlier redeemed. The aggregate net proceeds from the offering were approximately $841.4 million after deducting underwriting discounts and transaction expenses.

On September 3, 2019, Boston Properties Limited Partnership completed a public offering of $700.0 million in aggregate principal amount of its 2.900% unsecured senior notes due 2030. The notes were priced at 99.954% of the principal amount to yield an effective rate (including financing fees) of approximately 2.984% per annum to maturity. The notes will mature on March 15, 2030, unless earlier redeemed. The aggregate net proceeds from the offering were approximately $693.8 million after deducting underwriting discounts and transaction expenses.

On September 18, 2019, Boston Properties Limited Partnership completed the redemption of $700.0 million in aggregate principal amount of its 5.625% senior notes due November 15, 2020. The redemption price was approximately $740.7 million. The redemption price included approximately $13.5 million of accrued and unpaid interest to, but not including, the redemption date. Excluding the accrued and unpaid interest, the redemption price was approximately 103.90% of the principal amount being redeemed. The Company recognized a loss from early extinguishment of debt totaling approximately $28.0 million, which amount included the payment of the redemption premium totaling approximately $27.3 million.

The indenture relating to the unsecured senior notes contains certain financial restrictions and requirements, including (1) a leverage ratio not to exceed 60%, (2) a secured debt leverage ratio not to exceed 50%, (3) an interest coverage ratio of greater than 1.50 and (4) an unencumbered asset value of not less than 150% of unsecured debt. At September 30, 2019, Boston Properties Limited Partnership was in compliance with each of these financial restrictions and requirements.

Commitments And Contingencies	9 Months Ended
Commitments And Contingencies	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	7. Commitments and Contingencies General In the normal course of business, the Company guarantees its performance of services or indemnifies third parties against its negligence. In addition, in the normal course of business, the Company guarantees to certain tenants the obligations of its subsidiaries for the payment of tenant improvement allowances and brokerage commissions in connection with their leases and limited costs arising from delays in delivery of their premises. The Company has letter of credit and performance obligations related to lender and development requirements that total approximately $15.2 million. Certain of the Company’s joint venture agreements include provisions whereby, at certain specified times, each partner has the right to initiate a purchase or sale of its interest in the joint ventures. With limited exception, under these provisions, the Company is not compelled to purchase the interest of its outside joint venture partners. From time to time, under certain of the Company’s joint venture agreements, if certain return thresholds are achieved, either the Company or its partners will be entitled to an additional promoted interest or payments (See Note 8). From time to time, the Company (or ventures in which the Company has an ownership interest) has agreed, and may in the future agree, to (1) guarantee portions of the principal, interest and other amounts in connection with their borrowings, (2) provide customary environmental indemnifications and nonrecourse carve-outs (e.g., guarantees against fraud, misrepresentation and bankruptcy) in connection with their borrowings and (3) provide guarantees to lenders, tenants and other third parties for the completion of development projects. The Company has agreements with its outside partners whereby the partners agree to reimburse the joint venture for their share of any payments made under the guarantee. In some cases, the Company earns a fee from the applicable joint venture for providing the guarantee. In connection with the refinancing of 767 Fifth Avenue’s (the General Motors Building) secured loan by the Company’s consolidated joint venture entity, 767 Venture, LLC, the Company guaranteed the consolidated entity’s obligation to fund various reserves for tenant improvement costs and allowances, leasing commissions and free rent obligations in lieu of cash deposits. As of September 30, 2019, the maximum funding obligation under the guarantee was approximately $71.7 million. The Company earns a fee from the joint venture for providing the guarantee and has an agreement with the outside partners to reimburse the joint venture for their share of any payments made under the guarantee. As of September 30, 2019, no amounts related to the guarantee are recorded as liabilities in the Company’s consolidated financial statements. Pursuant to the lease agreement with Marriott, the Company has guaranteed the completion of the office building and parking garage on behalf of its 7750 Wisconsin Avenue joint venture and has also agreed to provide any financing guaranty that may be required with respect to third-party construction financing. The Company earns fees from the joint venture for providing the guarantees and any amounts the Company pays under the guarantee(s) will be deemed to be capital contributions by the Company to the joint venture. The Company has also agreed to fund construction costs through capital contributions to the joint venture in the event of unavailability or insufficiency of third-party construction financing. In addition, the Company has guaranteed to Marriott, as hotel manager, the completion of a hotel being developed by an affiliate of The Bernstein Companies (the Company’s partner in the 7750 Wisconsin Avenue joint venture) adjacent to the office property, for which the Company earns a fee from the affiliate of The Bernstein Companies. In addition, the Company entered into agreements with affiliates of The Bernstein Companies whereby the Company could be required to act as a mezzanine and/or mortgage lender and finance the construction of the hotel property. To secure such financing arrangements, affiliates of The Bernstein Companies are required to provide certain security, which varies depending on the specific loan, by pledges of their equity interest in the office property, a fee mortgage on the hotel property, or both. As of September 30, 2019, no amounts related to the contingent aspect of any of the guarantees are recorded as liabilities in the Company’s consolidated financial statements. In connection with the sale and development of the Company’s 6595 Springfield Center Drive development project, the Company has guaranteed the completion of the project and the payment of certain cost overruns in accordance with the development management agreement with the buyer. Although the project has been sold and the lease with the federal government tenant has been assigned to the buyer, pursuant to the terms of the Federal Government lease, the Federal Government tenant is not obligated to release the prior owner/landlord from such landlord’s obligations under the lease until completion of the construction. As a result, the entity which previously owned the land remains liable to the Federal Government tenant for the completion of the construction obligations under the lease. The buyer is obligated to fund the balance of the costs to meet such construction obligations, subject to the Company’s obligation to fund cost overruns (if any), as noted above. An affiliate of the buyer has provided a guaranty of the obligations of the buyer to fund such construction costs and the buyer has agreed to use commercially reasonable efforts to require the construction lender to provide certain remedies to the Company in the event the buyer does not fund such construction obligations. As of September 30, 2019, no amounts related to the contingent aspect of the guarantee are recorded as a liability in the Company’s consolidated financial statements. In connection with the redevelopment of the Company’s 325 Main Street property located in Cambridge, Massachusetts, the Company is required, pursuant to the local zoning ordinance, to commence construction of a residential building of at least 200,000 square feet with 25% of the project designated as income-restricted (with a minimum of 20% of the square footage devoted to home ownership units) prior to the occupancy of the 325 Main Street property. 325 Main Street consisted of an approximately 115,000 net rentable square foot Class A office property that is being demolished and developed into an approximately 420,000 net rentable square foot Class A office property, including approximately 41,000 net rentable square feet of retail space (See Note 3). In 2009, the Company filed a general unsecured creditor’s claim against Lehman Brothers, Inc. for approximately $45.3 million related to its rejection of a lease at 399 Park Avenue in New York City. On January 10, 2014, the trustee for the liquidation of the business of Lehman Brothers allowed the Company’s claim in the amount of approximately $45.2 million. During 2014, 2015, 2016, 2017 and 2018, the Company received distributions of approximately $7.7 million, $8.1 million, $1.4 million, $0.4 million and $0.3 million, respectively. The Company has a remaining claim of approximately $27.2 million. The Company will continue to evaluate whether to attempt to sell the remaining claim or wait until the trustee distributes proceeds from the Lehman Brothers estate. Given the inherent uncertainties in bankruptcy proceedings, there can be no assurance as to the timing or amount of additional proceeds, if any, that the Company may ultimately realize on the remaining claim, whether by sale to a third party or by one or more distributions from the trustee. Accordingly, the Company has not recorded any estimated recoveries associated with this gain contingency within its Consolidated Financial Statements at September 30, 2019. Insurance The Company’s property insurance program per occurrence limits are $1.0 billion for its portfolio insurance program, including coverage for acts of terrorism other than nuclear, biological, chemical or radiological terrorism (“Terrorism Coverage”). The Company also carries $250 million of Terrorism Coverage for 601 Lexington Avenue, New York, New York (“601 Lexington Avenue”) in excess of the $1.0 billion of coverage in the Company’s property insurance program. Certain properties, including the General Motors Building located at 767 Fifth Avenue in New York, New York (“767 Fifth Avenue”), are currently insured in separate insurance programs. The property insurance program per occurrence limits for 767 Fifth Avenue are $1.625 billion, including Terrorism Coverage. The Company also currently carries nuclear, biological, chemical and radiological terrorism insurance coverage for acts of terrorism certified under the Federal Terrorism Risk Insurance Act (as amended, “TRIA”) (“NBCR Coverage”), which is provided by IXP as a direct insurer, for the properties in the Company’s portfolio, including 767 Fifth Avenue, but excluding certain other properties owned in joint ventures with third parties or which the Company manages. The per occurrence limit for NBCR Coverage is $1.0 billion. Under TRIA, after the payment of the required deductible and coinsurance, the NBCR Coverage provided by IXP is backstopped by the Federal Government if the aggregate industry insured losses resulting from a certified act of terrorism exceed a “program trigger.” In 2019, the program trigger is $180 million and the coinsurance is 19%, however, both will increase in subsequent years pursuant to TRIA. If the Federal Government pays out for a loss under TRIA, it is mandatory that the Federal Government recoup the full amount of the loss from insurers offering TRIA coverage after the payment of the loss pursuant to a formula in TRIA. The Company may elect to terminate the NBCR Coverage if the Federal Government seeks recoupment for losses paid under TRIA, if TRIA is not extended after its expiration on December 31, 2020, if there is a change in its portfolio or for any other reason. The Company intends to continue to monitor the scope, nature and cost of available terrorism insurance. The Company also currently carries earthquake insurance on its properties located in areas known to be subject to earthquakes. In addition, this insurance is subject to a deductible in the amount of 3% of the value of the affected property. Specifically, the Company currently carries earthquake insurance which covers its San Francisco and Los Angeles regions with a $240 million per occurrence limit, and a $240 million annual aggregate limit, $20 million of which is provided by IXP, as a direct insurer. The amount of the Company’s earthquake insurance coverage may not be sufficient to cover losses from earthquakes. In addition, the amount of earthquake coverage could impact the Company’s ability to finance properties subject to earthquake risk. The Company may discontinue earthquake insurance or change the structure of its earthquake insurance program on some or all of its properties in the future if the premiums exceed the Company’s estimation of the value of the coverage. IXP, a captive insurance company which is a wholly-owned subsidiary of the Company, acts as a direct insurer with respect to a portion of the Company’s earthquake insurance coverage for its Greater San Francisco and Los Angeles properties and the Company’s NBCR Coverage. Insofar as the Company owns IXP, it is responsible for its liquidity and capital resources, and the accounts of IXP are part of the Company’s consolidated financial statements. In particular, if a loss occurs which is covered by the Company’s NBCR Coverage but is less than the applicable program trigger under TRIA, IXP would be responsible for the full amount of the loss without any backstop by the Federal Government. IXP would also be responsible for any recoupment charges by the Federal Government in the event losses are paid out and its insurance policy is maintained after the payout by the Federal Government. If the Company experiences a loss and IXP is required to pay under its insurance policy, the Company would ultimately record the loss to the extent of the required payment. Therefore, insurance coverage provided by IXP should not be considered as the equivalent of third-party insurance, but rather as a modified form of self-insurance. In addition, Boston Properties Limited Partnership has issued a guarantee to cover liabilities of IXP in the amount of $20.0 million. The mortgages on the Company’s properties typically contain requirements concerning the financial ratings of the insurers who provide policies covering the property. The Company provides the lenders on a regular basis with the identity of the insurance companies in the Company’s insurance programs. The ratings of some of the Company’s insurers are below the rating requirements in some of the Company’s loan agreements and the lenders for these loans could attempt to claim that an event of default has occurred under the loan. The Company believes it could obtain insurance with insurers which satisfy the rating requirements. Additionally, in the future, the Company’s ability to obtain debt financing secured by individual properties, or the terms of such financing, may be adversely affected if lenders generally insist on ratings for insurers or amounts of insurance which are difficult to obtain or which result in a commercially unreasonable premium. There can be no assurance that a deficiency in the financial ratings of one or more of the Company’s insurers will not have a material adverse effect on the Company. The Company continues to monitor the state of the insurance market in general, and the scope and costs of coverage for acts of terrorism and California earthquake risk in particular, but the Company cannot anticipate what coverage will be available on commercially reasonable terms in future policy years. There are other types of losses, such as from wars, for which the Company cannot obtain insurance at all or at a reasonable cost. With respect to such losses and losses from acts of terrorism, earthquakes or other catastrophic events, if the Company experiences a loss that is uninsured or that exceeds policy limits, the Company could lose the capital invested in the damaged properties, as well as the anticipated future revenues from those properties. Depending on the specific circumstances of each affected property, it is possible that the Company could be liable for mortgage indebtedness or other obligations related to the property. Any such loss could materially and adversely affect the Company’s business and financial condition and results of operations.

Noncontrolling Interests

9 Months Ended

Sep. 30, 2019

Noncontrolling Interest [Abstract]

Noncontrolling Interests

8. Noncontrolling Interests

Noncontrolling interests relate to the interests in Boston Properties Limited Partnership not owned by Boston Properties, Inc. and interests in consolidated property partnerships not wholly-owned by the Company. As of September 30, 2019, the noncontrolling interests in Boston Properties Limited Partnership consisted of 16,821,620 OP Units, 1,189,117 LTIP Units (including 118,067 2012 OPP Units, 68,659 2013 MYLTIP Units, 23,100 2014 MYLTIP Units, 28,724 2015 MYLTIP Units and 98,706 2016 MYLTIP Units), 394,921 2017 MYLTIP Units, 336,195 2018 MYLTIP Units and 220,734 2019 MYLTIP Units held by parties other than Boston Properties, Inc.

Noncontrolling Interest—Common Units

During the nine months ended September 30, 2019, 41,577 OP Units were presented by the holders for redemption (including 39,377 OP Units issued upon conversion of LTIP Units, 2012 OPP Units, 2013 MYLTIP Units, 2014 MYLTIP Units and 2016 MYLTIP Units) and were redeemed by Boston Properties, Inc. in exchange for an equal number of shares of Common Stock.

At September 30, 2019, Boston Properties Limited Partnership had outstanding 394,921 2017 MYLTIP Units, 336,195 2018 MYLTIP Units and 220,734 2019 MYLTIP Units. Prior to the applicable measurement date (February 6, 2020 for the 2017 MYLTIP Units, February 5, 2021 for the 2018 MYLTIP Units and February 4, 2022 for the 2019 MYLTIP Units), holders of MYLTIP Units will be entitled to receive per unit distributions equal to one-tenth (10%) of the regular quarterly distributions payable on an OP Unit, but will not be entitled to receive any special distributions. After the measurement date, the number of MYLTIP Units, both vested and unvested, that MYLTIP award recipients have earned, if any, based on the establishment of a performance pool, will be entitled to receive distributions in an amount per unit equal to distributions, both regular and special, payable on an OP Unit.

On February 9, 2019, the measurement period for the Company’s 2016 MYLTIP awards ended and, based on Boston Properties, Inc.’s relative TSR performance, the final awards were determined to be 69.5% of target or an aggregate of approximately $13.6 million (after giving effect to voluntary employee separations). As a result, an aggregate of 364,980 2016 MYLTIP Units that had been previously granted were automatically forfeited.

The following table presents Boston Properties Limited Partnership’s distributions on the OP Units and LTIP Units (including the 2012 OPP Units, 2013 MYLTIP Units, 2014 MYLTIP Units and 2015 MYLTIP Units and, after the February 9, 2019 measurement date, the 2016 MYLTIP Units) and its distributions on the 2016 MYLTIP Units (prior to the February 9, 2019 measurement date), 2017 MYLTIP Units, 2018 MYLTIP Units and 2019 MYLTIP Units (after the February 5, 2019 issuance date) paid in 2019:



Record Date	Payment Date	Distributions per OP Unit and LTIP Unit		Distributions per MYLTIP Unit
September 30, 2019	October 31, 2019		$0.95		$0.095
June 28, 2019	July 31, 2019		$0.95		$0.095
March 29, 2019	April 30, 2019		$0.95		$0.095
December 31, 2018	January 30, 2019		$0.95		$0.095

The following table presents Boston Properties Limited Partnership’s distributions on the OP Units and LTIP Units (including the 2012 OPP Units, 2013 MYLTIP Units, 2014 MYLTIP Units and, after the February 4, 2018 measurement date, the 2015 MYLTIP Units) and its distributions on the 2015 MYLTIP Units (prior to the February 4, 2018 measurement date), 2016 MYLTIP Units, 2017 MYLTIP Units and 2018 MYLTIP Units (after the February 6, 2018 issuance date) that occurred during the nine months ended September 30, 2018:



Record Date	Payment Date	Distributions per OP Unit and LTIP Unit		Distributions per MYLTIP Unit
September 28, 2018	October 31, 2018		$0.95		$0.095
June 29, 2018	July 31, 2018		$0.80		$0.080
March 29, 2018	April 30, 2018		$0.80		$0.080
December 31, 2017	January 30, 2018		$0.80		$0.080

A holder of an OP Unit may present the OP Unit to Boston Properties Limited Partnership for redemption at any time (subject to restrictions agreed upon at the time of issuance of OP Units to particular holders that may restrict such redemption right for a period of time, generally one year from issuance). Upon presentation of an OP Unit for redemption, Boston Properties Limited Partnership must redeem the OP Unit for cash equal to the then value of a share of common stock of Boston Properties, Inc. Boston Properties, Inc. may, in its sole discretion, elect to assume and satisfy the redemption obligation by paying either cash or issuing one share of Common Stock. The value of the OP Units not owned by Boston Properties, Inc. and LTIP Units (including the 2012 OPP Units, 2013 MYLTIP Units, 2014 MYLTIP Units, 2015 MYLTIP Units and 2016 MYLTIP Units), assuming that all conditions had been met for the conversion thereof, had all of such units been redeemed at September 30, 2019 was approximately $2.3 billion based on the last reported price of a share of Common Stock on the New York Stock Exchange of $129.66 per share on September 30, 2019.

Noncontrolling Interests—Property Partnerships

The noncontrolling interests in property partnerships consist of the outside equity interests in ventures that are consolidated with the financial results of the Company because the Company exercises control over the entities that own the properties. The equity interests in these ventures that are not owned by the Company, totaling approximately $1.7 billion at September 30, 2019 and December 31, 2018, are included in Noncontrolling Interests—Property Partnerships in the accompanying Consolidated Balance Sheets.

On May 12, 2016, the partners in the Company’s consolidated entity that owns Salesforce Tower located in San Francisco, California amended the venture agreement. Under the original venture agreement, if the Company elected to fund the construction of Salesforce Tower without a construction loan (or a construction loan of less than 50% of project costs) and the venture commenced vertical construction of the project, then the partner’s capital funding obligation would be limited, in which event the Company would fund up to 2.5% of the total project costs (i.e., 50% of the partner’s 5% interest in the venture) in the form of a loan to the partner. This loan would bear interest at the then prevailing market interest rates for construction loans. Under the amended agreement, the partners agreed to structure this funding by the Company as preferred equity rather than a loan. The preferred equity contributed by the Company earned a preferred return equal to LIBOR plus 3.00% per annum and was payable to the Company out of any distributions to which the partner would otherwise be entitled until such preferred equity and preferred return was repaid to the Company. The Company contributed an aggregate of approximately $22.6 million of preferred equity to the venture. Also, under the joint venture agreement, (a) from and after the stabilization date, the partner had the right to cause the Company to purchase all (but not less than all) of the partner’s interest and (b) from and after the third anniversary of the stabilization date, the Company had the right to acquire all (but not less than all) of the partner’s interest, in each case at an agreed upon purchase price or appraised value. In addition, if certain threshold returns were achieved the partner would be entitled to receive an additional promoted interest with respect to cash flow distributions. The term stabilization date was defined in the agreement to generally mean the first date after completion upon which Salesforce Tower is (1) at least 90% leased and (2) 50% occupied by tenants that are paying rent. Salesforce Tower is an approximately 1,421,000 net rentable square foot Class A office property.

On January 18, 2019, the Company and its partner amended the venture agreement. Per the amendment, the partner exercised its right to cause the Company to purchase on April 1, 2019 its 5% ownership interest and promoted profits interest in the venture for cash totaling approximately $210.9 million, which amount was reduced by approximately $24.1 million, consisting of the repayment of the Company’s preferred equity and preferred return as provided for in the venture agreement.

On April 1, 2019, the Company completed the acquisition of its partner’s 5% ownership interest and promoted profits interest in the consolidated entity for cash totaling approximately $210.9 million, which amount was reduced by approximately $24.1 million to $186.8 million to reflect the repayment of the Company's preferred equity and preferred return in the venture, as described above. The Company now owns 100% of Salesforce Tower. The Company has accounted for the transaction as an equity transaction for financial reporting purposes and has reflected the difference between the fair value of the total consideration paid and the related carrying value of the noncontrolling interest - property partnership totaling approximately $162.5 million as a decrease to Additional Paid-in Capital and Partners’ Capital in the Consolidated Balance Sheets of Boston Properties, Inc. and Boston Properties Limited Partnership, respectively.

Stockholders' Equity / Partners' Capital

9 Months Ended

Sep. 30, 2019

Equity [Abstract]

Stockholders' Equity / Partners' Capital

9. Stockholders’ Equity / Partners’ Capital

As of September 30, 2019, Boston Properties, Inc. had 154,572,073 shares of Common Stock outstanding.

As of September 30, 2019, Boston Properties, Inc. owned 1,725,828 general partnership units and 152,846,245 limited partnership units of Boston Properties Limited Partnership.

On June 2, 2017, Boston Properties, Inc. renewed its “at the market” (“ATM”) stock offering program through which it may sell from time to time up to an aggregate of $600.0 million of its common stock through sales agents over a three-year period. This program replaced the Company’s prior $600.0 million ATM stock offering program that was scheduled to expire on June 3, 2017. The Company intends to use the net proceeds from any offering for general business purposes, which may include investment opportunities and debt reduction. No shares of common stock have been issued under this ATM stock offering program.

During the nine months ended September 30, 2019, Boston Properties, Inc. issued 29,704 shares of Common Stock upon the exercise of options to purchase Common Stock.

During the nine months ended September 30, 2019, Boston Properties, Inc. issued 41,577 shares of Common Stock in connection with the redemption of an equal number of redeemable OP Units from limited partners.

The following table presents Boston Properties, Inc.’s dividends per share and Boston Properties Limited Partnership’s distributions per OP Unit and LTIP Unit paid or declared in 2019 and during the nine months ended September 30, 2018:



Record Date	Payment Date	Dividend (Per Share)		Distribution (Per Unit)
September 30, 2019	October 31, 2019		$0.95		$0.95
June 28, 2019	July 31, 2019		$0.95		$0.95
March 29, 2019	April 30, 2019		$0.95		$0.95
December 31, 2018	January 30, 2019		$0.95		$0.95

September 28, 2018	October 31, 2018		$0.95		$0.95
June 29, 2018	July 31, 2018		$0.80		$0.80
March 29, 2018	April 30, 2018		$0.80		$0.80
December 31, 2017	January 30, 2018		$0.80		$0.80

Preferred Stock

As of September 30, 2019, Boston Properties, Inc. had 80,000 shares (8,000,000 depositary shares each representing 1/100th of a share) outstanding of its 5.25% Series B Cumulative Redeemable Preferred Stock with a liquidation preference of $2,500.00 per share ($25.00 per depositary share). Boston Properties, Inc. pays cumulative cash dividends on the Series B Preferred Stock at a rate of 5.25% per annum of the $2,500.00 liquidation preference per share. Boston Properties, Inc., at its option, may redeem the Series B Preferred Stock for a cash redemption price of $2,500.00 per share ($25.00 per depositary share), plus all accrued and unpaid dividends. The Series B Preferred Stock is not redeemable by the holders, has no maturity date and is not convertible into any other security of Boston Properties, Inc. or its affiliates.

The following table presents Boston Properties, Inc.’s dividends per share on its outstanding Series B Preferred Stock paid or declared during 2019 and during the nine months ended September 30, 2018:



Record Date	Payment Date	Dividend (Per Share)
November 1, 2019	November 15, 2019		$32.8125
August 2, 2019	August 15, 2019		$32.8125
May 3, 2019	May 15, 2019		$32.8125
February 4, 2019	February 15, 2019		$32.8125

November 2, 2018	November 15, 2018		$32.8125
August 3, 2018	August 15, 2018		$32.8125
May 4, 2018	May 15, 2018		$32.8125
February 2, 2018	February 15, 2018		$32.8125

Earnings Per Share / Common Unit

9 Months Ended

Sep. 30, 2019

Earnings Per Share [Abstract]

Earnings Per Share / Common Unit

10. Earnings Per Share / Common Unit

Boston Properties, Inc.

The following table provides a reconciliation of both the net income attributable to Boston Properties, Inc. common shareholders and the number of common shares used in the computation of basic earnings per share (“EPS”), which is calculated by dividing net income attributable to Boston Properties, Inc. common shareholders by the weighted-average number of common shares outstanding during the period. Unvested share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents (whether paid or unpaid) are also

participating securities. As such, unvested restricted common stock of Boston Properties, Inc. and Boston Properties Limited Partnership’s LTIP Units, 2012 OPP Units and MYLTIP Units are considered participating securities. Participating securities are included in the computation of basic EPS of Boston Properties, Inc. using the two-class method. Participating securities are included in the computation of diluted EPS of Boston Properties, Inc. using the if-converted method if the impact is dilutive. Because the 2012 OPP Units, 2013 MYLTIP Units, 2014 MYLTIP Units, 2015 MYLTIP Units and 2016 MYLTIP Units required, and the 2017-2019 MYLTIP Units require, Boston Properties, Inc. to outperform absolute and relative return thresholds, unless such thresholds have been met by the end of the applicable reporting period, Boston Properties, Inc. excludes such units from the diluted EPS calculation. Other potentially dilutive common shares, including stock options, restricted stock and other securities of Boston Properties Limited Partnership that are exchangeable for Boston Properties, Inc.’s Common Stock, and the related impact on earnings, are considered when calculating diluted EPS.



	Three months ended September 30, 2019
	Income (Numerator)		Shares (Denominator)	Per Share Amount
	(in thousands, except for per share amounts)
Basic Earnings:
Net income attributable to Boston Properties, Inc. common shareholders	$	107,771	154,577	$	0.70
Effect of Dilutive Securities:
Stock Based Compensation	—		243	—
Diluted Earnings:
Net income attributable to Boston Properties, Inc. common shareholders	$	107,771	154,820	$	0.70

	Three months ended September 30, 2018
	Income (Numerator)		Shares (Denominator)	Per Share Amount
	(in thousands, except for per share amounts)
Basic Earnings:
Net income attributable to Boston Properties, Inc. common shareholders	$	119,118	154,440	$	0.77
Effect of Dilutive Securities:
Stock Based Compensation	—		238	—
Diluted Earnings:
Net income attributable to Boston Properties, Inc. common shareholders	$	119,118	154,678	$	0.77

	Nine months ended September 30, 2019
	Income (Numerator)		Shares (Denominator)	Per Share Amount
	(in thousands, except for per share amounts)
Basic Earnings:
Net income attributable to Boston Properties, Inc. common shareholders	$	370,200	154,553	$	2.40
Effect of Dilutive Securities:
Stock Based Compensation	—		294	(0.01		)
Diluted Earnings:
Net income attributable to Boston Properties, Inc. common shareholders	$	370,200	154,847	$	2.39



	Nine months ended September 30, 2018
	Income (Numerator)			Shares (Denominator)	Per Share Amount
	(in thousands, except for per share amounts)
Basic Earnings:
Net income attributable to Boston Properties, Inc. common shareholders	$	423,835		154,414	$	2.74
Allocation of undistributed earnings to participating securities	(87		)	—	—
Net income attributable to Boston Properties, Inc. common shareholders	$	423,748		154,414	$	2.74
Effect of Dilutive Securities:
Stock Based Compensation	—			238	—
Diluted Earnings:
Net income attributable to Boston Properties, Inc. common shareholders	$	423,748		154,652	$	2.74

Boston Properties Limited Partnership

The following table provides a reconciliation of both the net income attributable to Boston Properties Limited Partnership common unitholders and the number of common units used in the computation of basic earnings per common unit, which is calculated by dividing net income attributable to Boston Properties Limited Partnership common unitholders by the weighted-average number of common units outstanding during the period. Unvested share-based payment awards that contain non-forfeitable rights to dividends or dividend equivalents (whether paid or unpaid) are also participating securities. As such, unvested restricted common stock of Boston Properties, Inc. and Boston Properties Limited Partnership’s LTIP Units, 2012 OPP Units and MYLTIP Units are considered participating securities. Participating securities are included in the computation of basic earnings per common unit using the two-class method. Participating securities are included in the computation of diluted earnings per common unit using the if-converted method if the impact is dilutive. Because the 2012 OPP Units, 2013 MYLTIP Units, 2014 MYLTIP Units, 2015 MYLTIP Units and 2016 MYLTIP Units required, and the 2017-2019 MYLTIP Units require, Boston Properties, Inc. to outperform absolute and relative return thresholds, unless such thresholds have been met by the end of the applicable reporting period, Boston Properties Limited Partnership excludes such units from the diluted earnings per common unit calculation. Other potentially dilutive common units and the related impact on earnings are considered when calculating diluted earnings per common unit. Included in the number of units (the denominator) below are approximately 17,638,000 and 17,488,000 redeemable common units for the three months ended September 30, 2019 and 2018, respectively, and 17,630,000 and 17,490,000 redeemable common units for the nine months ended September 30, 2019 and 2018, respectively.



	Three months ended September 30, 2019
	Income (Numerator)		Units (Denominator)	Per Unit Amount
	(in thousands, except for per unit amounts)
Basic Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	122,117	172,215	$	0.71
Effect of Dilutive Securities:
Stock Based Compensation	—		243	—
Diluted Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	122,117	172,458	$	0.71



	Three months ended September 30, 2018
	Income (Numerator)			Units (Denominator)	Per Unit Amount
	(in thousands, except for per unit amounts)
Basic Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	136,201		171,928	$	0.79
Effect of Dilutive Securities:
Stock Based Compensation	—			238	—
Diluted Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	136,201		172,166	$	0.79

	Nine months ended September 30, 2019
	Income (Numerator)			Units (Denominator)	Per Unit Amount
	(in thousands, except for per unit amounts)
Basic Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	421,214		172,183	$	2.45
Effect of Dilutive Securities:
Stock Based Compensation	—			294	(0.01		)
Diluted Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	421,214		172,477	$	2.44

	Nine months ended September 30, 2018
	Income (Numerator)			Units (Denominator)	Per Unit Amount
	(in thousands, except for per unit amounts)
Basic Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	483,069		171,904	$	2.81
Allocation of undistributed earnings to participating securities	(97		)	—	—
Net income attributable to Boston Properties Limited Partnership common unitholders	$	482,972		171,904	$	2.81
Effect of Dilutive Securities:
Stock Based Compensation	—			238	—
Diluted Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	482,972		172,142	$	2.81

Stock Option and Incentive Plan	9 Months Ended
Stock Option and Incentive Plan	Sep. 30, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option and Incentive Plan	11. Stock Option and Incentive Plan On February 5, 2019, Boston Properties, Inc.’s Compensation Committee approved the 2019 MYLTIP awards under the 2012 Plan to certain officers and employees of Boston Properties, Inc. The 2019 MYLTIP awards utilize Boston Properties, Inc.’s TSR over a three year measurement period, on an annualized, compounded basis, as the performance metric. Earned awards will be based on Boston Properties, Inc.’s TSR relative to the Nareit Office Index adjusted to include Vornado Realty Trust. Earned awards will range from zero to a maximum of 220,734 LTIP Units depending on Boston Properties, Inc.’s TSR relative to the Nareit Office Index adjusted to include Vornado Realty Trust, with a target of approximately 110,367 LTIP Units and linear interpolation between zero and maximum. Earned awards (if any) will vest 50% on February 4, 2022 and 50% on February 4, 2023, based on continued employment. Vesting will be accelerated in the event of a change in control, termination of employment by Boston Properties, Inc. without cause, or termination of employment by the award recipient for good reason, death, disability or retirement. If there is a change of control prior to February 4, 2022, earned awards will be calculated based on TSR performance up to the date of the change of control. The 2019 MYLTIP awards are in the form of LTIP Units issued on the grant date which (i) are subject to forfeiture to the extent awards are not earned and (ii) prior to the performance measurement date are only entitled to one-tenth (10%) of the regular quarterly distributions payable on common partnership units. Under ASC 718 “Compensation - Stock Compensation”, the 2019 MYLTIP awards have an aggregate value of approximately $13.5 million, which amount will generally be amortized into earnings over the four year plan period under the graded vesting method. On February 9, 2019, the measurement period for the Company’s 2016 MYLTIP awards ended and, based on Boston Properties, Inc.’s relative TSR performance, the final awards were determined to be 69.5% of target or an aggregate of approximately $13.6 million (after giving effect to voluntary employee separations). As a result, an aggregate of 364,980 2016 MYLTIP Units that had been previously granted were automatically forfeited. During the nine months ended September 30, 2019, Boston Properties, Inc. issued 26,503 shares of restricted common stock and Boston Properties Limited Partnership issued 181,919 LTIP Units and 220,734 2019 MYLTIP Units to employees and non-employee directors under the 2012 Plan. Employees and non-employee directors paid $0.01 per share of restricted common stock and $0.25 per LTIP Unit and 2019 MYLTIP Unit. When issued, LTIP Units are not economically equivalent in value to a share of Common Stock, but over time can increase in value to one-for-one parity with Common Stock if there is sufficient appreciation in the value of the Company’s assets. The aggregate value of the LTIP Units is included in noncontrolling interests in the Consolidated Balance Sheets of Boston Properties, Inc. and Boston Properties Limited Partnership. A substantial majority of the grants of restricted common stock and LTIP Units to employees vest in four equal annual installments. Restricted common stock is measured at fair value on the date of grant based on the number of shares granted and the closing price of Boston Properties, Inc.’s Common Stock on the date of grant as quoted on the New York Stock Exchange. Such value is recognized as an expense ratably over the corresponding employee service period. The shares of restricted common stock granted during the nine months ended September 30, 2019 were valued at approximately $3.5 million ($131.27 per share weighted-average). The LTIP Units granted were valued at approximately $22.1 million (approximately $121.50 per unit weighted-average fair value) using a Monte Carlo simulation method model. The per unit fair values of the LTIP Units granted were estimated on the dates of grant and for a substantial majority of such units were valued using the following assumptions: an expected life of 5.7 years, a risk-free interest rate of 2.68% and an expected price volatility of 27.0%. Because the 2012 OPP Units, 2013 MYLTIP Units, 2014 MYLTIP Units, 2015 MYLTIP Units, 2016 MYLTIP Units, 2017 MYLTIP Units, 2018 MYLTIP Units and 2019 MYLTIP Units are subject to both a service condition and a market condition, the Company recognizes the related compensation expense under the graded vesting attribution method. Under the graded vesting attribution method, each portion of the award that vests at a different date is accounted for as a separate award and recognized over the period appropriate to that portion so that the compensation cost for each portion should be recognized in full by the time that portion vests. The Company recognizes forfeitures as they occur on its awards of stock-based compensation. Dividends paid on both vested and unvested shares of restricted stock are charged directly to Dividends in Excess of Earnings in Boston Properties, Inc.’s Consolidated Balance Sheets and Partners’ Capital in Boston Properties Limited Partnership’s Consolidated Balance Sheets. Aggregate stock-based compensation expense associated with restricted stock, LTIP Units, 2015 MYLTIP Units, 2016 MYLTIP Units, 2017 MYLTIP Units, 2018 MYLTIP Units and 2019 MYLTIP Units was approximately $7.5 million and $7.9 million for the three months ended September 30, 2019 and 2018, respectively, and approximately $32.4 million and $30.1 million for the nine months ended September 30, 2019 and 2018, respectively. At September 30, 2019, there was (1) an aggregate of approximately $28.9 million of unrecognized compensation expense related to unvested restricted stock, LTIP Units and 2016 MYLTIP Units and (2) an aggregate of approximately $15.1 million of unrecognized compensation expense related to unvested 2017 MYLTIP Units, 2018 MYLTIP Units and 2019 MYLTIP Units that is expected to be recognized over a weighted-average period of approximately 2.5 years.

Segment Information

9 Months Ended

Sep. 30, 2019

Segment Reporting [Abstract]

Segment Information

12. Segment Information

The following tables present reconciliations of Net Income Attributable to Boston Properties, Inc. Common Shareholders to the Company’s share of Net Operating Income and Net Income Attributable to Boston Properties Limited Partnership Common Unitholders to the Company’s share of Net Operating Income for the three and nine months ended September 30, 2019 and 2018.

Boston Properties, Inc.



	Three months ended September 30,						Nine months ended September 30,
	2019			2018			2019		2018
	(in thousands)
Net income attributable to Boston Properties, Inc. common shareholders	$	107,771		$	119,118		$	370,200	$	423,835
Add:
Preferred dividends	2,625			2,625			7,875		7,875
Noncontrolling interest—common units of Boston Properties Limited Partnership	12,504			13,852			43,133		49,128
Noncontrolling interests in property partnerships	18,470			14,850			54,782		46,484
Interest expense	106,471			95,366			309,837		277,790
Loss from early extinguishment of debt	28,010			—			28,010		—
Impairment loss	—			—			24,038		—
Net operating income from unconsolidated joint ventures	23,065			22,511			73,129		54,798
Depreciation and amortization expense	165,862			157,996			507,867		480,210
Transaction costs	538			914			1,415		1,409
Payroll and related costs from management services contracts	2,429			2,516			8,227		7,371
General and administrative expense	31,147			29,677			107,980		94,039
Less:
Net operating income attributable to noncontrolling interests in property partnerships	46,249			43,068			138,896		132,026
Gains from investments in securities	106			1,075			4,240		1,454
Interest and other income	7,178			2,822			14,546		7,049
Gains (losses) on sales of real estate	(15		)	7,863			766		122,552
Income (loss) from unconsolidated joint ventures	(649		)	(4,313		)	47,528		(3,083		)
Direct reimbursements of payroll and related costs from management services contracts	2,429			2,516			8,227		7,371
Development and management services revenue	10,303			15,253			29,566		32,963
Company’s share of Net Operating Income	$	433,291		$	391,141		$	1,292,724	$	1,142,607

Boston Properties Limited Partnership



	Three months ended September 30,						Nine months ended September 30,
	2019			2018			2019		2018
	(in thousands)
Net income attributable to Boston Properties Limited Partnership common unitholders	$	122,117		$	136,201		$	421,214	$	483,069
Add:
Preferred distributions	2,625			2,625			7,875		7,875
Noncontrolling interests in property partnerships	18,470			14,850			54,782		46,484
Interest expense	106,471			95,366			309,837		277,790
Loss from early extinguishment of debt	28,010			—			28,010		—
Impairment loss	—			—			22,272		—
Net operating income from unconsolidated joint ventures	23,065			22,511			73,129		54,798
Depreciation and amortization expense	164,020			156,056			501,901		474,383
Transaction costs	538			914			1,415		1,409
Payroll and related costs from management services contracts	2,429			2,516			8,227		7,371
General and administrative expense	31,147			29,677			107,980		94,039
Less:
Net operating income attributable to noncontrolling interests in property partnerships	46,249			43,068			138,896		132,026
Gains from investments in securities	106			1,075			4,240		1,454
Interest and other income	7,178			2,822			14,546		7,049
Gains (losses) on sales of real estate	(15		)	9,154			915		126,831
Income (loss) from unconsolidated joint ventures	(649		)	(4,313		)	47,528		(3,083		)
Direct reimbursements of payroll and related costs from management services contracts	2,429			2,516			8,227		7,371
Development and management services revenue	10,303			15,253			29,566		32,963
Company’s share of Net Operating Income	$	433,291		$	391,141		$	1,292,724	$	1,142,607

Net operating income (“NOI”) is a non-GAAP financial measure equal to net income attributable to Boston Properties, Inc. common shareholders and net income attributable to Boston Properties Limited Partnership common unitholders, as applicable, the most directly comparable GAAP financial measures, plus (1) preferred dividends/distributions, net income attributable to noncontrolling interests, interest expense, loss from early extinguishment of debt, impairment loss, depreciation and amortization expense, transaction costs, payroll and related costs from management services contracts and corporate general and administrative expense less (2) gains from investments in securities, interest and other income, gains (losses) on sales of real estate, income (loss) from unconsolidated joint ventures, direct reimbursements of payroll and related costs from management services contracts and development and management services revenue. The Company believes NOI is useful to investors as a performance measure and believes it provides useful information to investors regarding the Company’s results of operations and financial condition because, when compared across periods, it reflects the impact on operations from trends in occupancy rates, rental rates, operating costs and acquisition and development activity on an unleveraged basis, providing perspective not immediately apparent from net income attributable to Boston Properties, Inc. common shareholders and net income attributable to Boston Properties Limited Partnership common unitholders. For example, interest expense is not necessarily linked to the operating performance of a real estate asset and is often incurred at the corporate level as opposed to the property level. Similarly, interest expense may be incurred at the property level even though the financing proceeds may be used at the corporate level (e.g., used for other investment activity). In addition, depreciation and amortization expense, because of historical cost accounting and useful life estimates, may distort operating performance measures at the property

level. NOI presented by the Company may not be comparable to NOI reported by other REITs or real estate companies that define NOI differently.

The Company’s internal reporting utilizes its share of NOI, which includes its share of NOI from consolidated and unconsolidated joint ventures, which is a non-GAAP financial measure that is calculated as the consolidated amount, plus the Company’s share of the amount from the Company’s unconsolidated joint ventures (calculated based upon the Company’s percentage ownership interest and, in some cases, after priority allocations), minus the Company’s partners’ share of the amount from the Company’s consolidated joint ventures (calculated based upon the partners’ percentage ownership interests and, in some cases, after priority allocations, income allocation to private REIT shareholders and their share of fees due to the Company). The Company’s share of NOI from unconsolidated joint ventures does not include its share of gains on sale of real estate from unconsolidated joint ventures which is included within income (loss) from unconsolidated joint ventures in the Company’s Consolidated Statements of Operations. Management utilizes its share of NOI in assessing its performance as the Company has several significant joint ventures and, in some cases, the Company exercises significant influence over, but does not control, the joint venture, in which case GAAP requires that the Company account for the joint venture entity using the equity method of accounting and the Company does not consolidate it for financial reporting purposes. In other cases, GAAP requires that the Company consolidate the venture even though the Company’s partner(s) owns a significant percentage interest. As a result, the presentations of the Company’s share of NOI should not be considered a substitute for, and should only be considered together with and as a supplement to, the Company’s financial information presented in accordance with GAAP.

Asset information by segment is not reported because the Company does not use this measure to assess performance. Therefore, depreciation and amortization expense is not allocated among segments. Preferred dividends/distributions, interest expense, loss from early extinguishment of debt, impairment loss, depreciation and amortization expense, transaction costs, payroll and related costs from management services contracts, corporate general and administrative expense, gains from investments in securities, interest and other income, gains on sales of real estate, direct reimbursements of payroll and related costs from management services contracts and development and management services revenue are not included in NOI and are provided as reconciling items to the Company’s reconciliations of its share of NOI to net income attributable to common shareholders/unitholders.

The Company’s segments are based on the Company’s method of internal reporting which classifies its operations by geographic area. The Company’s segments by geographic area are Boston, Los Angeles, New York, San Francisco and Washington, DC. The Company also presents information for each segment by property type including Office, Residential and Hotel.

Beginning in 2019, the Company modified the presentation of its geographic area classification for all periods presented to include the Los Angeles geographic area to align with its method of internal reporting. The Company expanded its presence in the Los Angeles geographic area with its equity method investment in Santa Monica Business Park located in Santa Monica, California. As of September 30, 2019, the Company has equity interests in a portfolio of 27 office and retail properties in the Los Angeles geographic area aggregating approximately 2.3 million net rentable square feet, all of which are owned through investments in unconsolidated joint ventures. The Company is presenting the Los Angeles geographic area as a reportable segment to align with its method of internal reporting given the increased significance as a result of commencing a full reporting period of ownership of the Santa Monica Business Park portfolio. The inclusion of the Los Angeles geographic area has also resulted in a change in the reported measure of segment profit or loss from NOI to the Company’s share of NOI. This change has been reflected in all periods presented and the impact of the change can been seen within the tables below. The Company has not presented rental revenue and rental expenses for properties owned through investments in unconsolidated joint ventures, including those in the Los Angeles geographic area, as the Company accounts for these properties using the equity method of accounting.

Information by geographic area (dollars in thousands):

For the three months ended September 30, 2019:



	Boston			Los Angeles			New York			San Francisco			Washington, DC			Total
Rental Revenue: (1)
Office	$	224,345		$	—		$	251,806		$	136,290		$	95,370		$	707,811
Residential	3,809			—			—			—			6,187			9,996
Hotel	13,014			—			—			—			—			13,014
Total	241,168			—			251,806			136,290			101,557			730,821
% of Grand Totals	33.00		%	—		%	34.45		%	18.65		%	13.90		%	100.00		%
Rental Expenses:
Office	81,278			—			98,698			45,900			35,716			261,592
Residential	1,244			—			—			—			2,767			4,011
Hotel	8,743			—			—			—			—			8,743
Total	91,265			—			98,698			45,900			38,483			274,346
% of Grand Totals	33.27		%	—		%	35.97		%	16.73		%	14.03		%	100.00		%
Net operating income	$	149,903		$	—		$	153,108		$	90,390		$	63,074		$	456,475
% of Grand Totals	32.84		%	—		%	33.54		%	19.80		%	13.82		%	100.00		%
Less: Net operating income attributable to noncontrolling interests in property partnerships	(10,379		)	—			(35,870		)	—			—			(46,249		)
Add: Company’s share of net operating income from unconsolidated joint ventures	1,686			14,702			(27		)	—			6,704			23,065
Company’s share of net operating income	$	141,210		$	14,702		$	117,211		$	90,390		$	69,778		$	433,291
% of Grand Totals	32.60		%	3.39		%	27.05		%	20.86		%	16.10		%	100.00		%

_______________


(1)	Rental Revenue is equal to Total Revenue per the Company’s Consolidated Statements of Operations, less Development and Management Services Revenue and Direct Reimbursements of Payroll and Related Costs from Management Services Contracts Revenue per the Consolidated Statements of Operations.

For the three months ended September 30, 2018:



	Boston			Los Angeles			New York			San Francisco			Washington, DC			Total
Rental Revenue: (1)
Office	$	210,277		$	—		$	237,944		$	102,035		$	98,275		$	648,531
Residential	1,905			—			—			—			4,415			6,320
Hotel	13,664			—			—			—			—			13,664
Total	225,846			—			237,944			102,035			102,690			668,515
% of Grand Totals	33.78		%	—		%	35.60		%	15.26		%	15.36		%	100.00		%
Rental Expenses:
Office	78,089			—			96,795			34,016			35,365			244,265
Residential	1,159			—			—			—			2,565			3,724
Hotel	8,828			—			—			—			—			8,828
Total	88,076			—			96,795			34,016			37,930			256,817
% of Grand Totals	34.30		%	—		%	37.68		%	13.25		%	14.77		%	100.00		%
Net operating income	$	137,770		$	—		$	141,149		$	68,019		$	64,760		$	411,698
% of Grand Totals	33.46		%	—		%	34.29		%	16.52		%	15.73		%	100.00		%
Less: Net operating income attributable to noncontrolling interests in property partnerships	(8,332		)	—			(34,723		)	(13		)	—			(43,068		)
Add: Company’s share of net operating income from unconsolidated joint ventures	781			13,246			1,698			—			6,786			22,511
Company’s share of net operating income	$	130,219		$	13,246		$	108,124		$	68,006		$	71,546		$	391,141
% of Grand Totals	33.29		%	3.39		%	27.64		%	17.39		%	18.29		%	100.00		%

_______________


(1)	Rental Revenue is equal to Total Revenue per the Company’s Consolidated Statements of Operations, less Development and Management Services Revenue and Direct Reimbursements of Payroll and Related Costs from Management Services Contracts Revenue per the Consolidated Statements of Operations.

For the nine months ended September 30, 2019:



	Boston			Los Angeles			New York			San Francisco			Washington, DC			Total
Rental Revenue: (1)
Office	$	659,717		$	—		$	761,993		$	391,851		$	288,201		$	2,101,762
Residential	9,732			—			—			—			16,978			26,710
Hotel	36,796			—			—			—			—			36,796
Total	706,245			—			761,993			391,851			305,179			2,165,268
% of Grand Totals	32.62		%	—		%	35.19		%	18.10		%	14.09		%	100.00		%
Rental Expenses:
Office	238,438			—			292,478			130,733			107,535			769,184
Residential	3,729			—			—			—			8,178			11,907
Hotel	25,686			—			—			—			—			25,686
Total	267,853			—			292,478			130,733			115,713			806,777
% of Grand Totals	33.20		%	—		%	36.26		%	16.20		%	14.34		%	100.00		%
Net operating income	$	438,392		$	—		$	469,515		$	261,118		$	189,466		$	1,358,491
% of Grand Totals	32.27		%	—		%	34.56		%	19.22		%	13.95		%	100.00		%
Less: Net operating income attributable to noncontrolling interests in property partnerships	(29,783		)	—			(108,665		)	(448		)	—			(138,896		)
Add: Company’s share of net operating income from unconsolidated joint ventures	3,276			45,864			3,455			—			20,534			73,129
Company’s share of net operating income	$	411,885		$	45,864		$	364,305		$	260,670		$	210,000		$	1,292,724
% of Grand Totals	31.87		%	3.55		%	28.18		%	20.16		%	16.24		%	100.00		%

_______________


(1)	Rental Revenue is equal to total Revenue per the Company’s Consolidated Statements of Operations, less Development and Management Services Revenue and Direct Reimbursements of Payroll and Related Costs from Management Services Contracts Revenue per the Consolidated Statements of Operations.

For the nine months ended September 30, 2018:



	Boston			Los Angeles			New York			San Francisco			Washington, DC			Total
Rental Revenue: (1)
Office	$	623,084		$	—		$	714,348		$	285,410		$	296,092		$	1,918,934
Residential	4,252			—			—			—			11,026			15,278
Hotel	37,373			—			—			—			—			37,373
Total	664,709			—			714,348			285,410			307,118			1,971,585
% of Grand Totals	33.71		%	—		%	36.23		%	14.48		%	15.58		%	100.00		%
Rental Expenses:
Office	235,560			—			282,395			92,858			106,386			717,199
Residential	2,379			—			—			—			6,530			8,909
Hotel	25,642			—			—			—			—			25,642
Total	263,581			—			282,395			92,858			112,916			751,750
% of Grand Totals	35.06		%	—		%	37.57		%	12.35		%	15.02		%	100.00		%
Net operating income	$	401,128		$	—		$	431,953		$	192,552		$	194,202		$	1,219,835
% of Grand Totals	32.88		%	—		%	35.41		%	15.79		%	15.92		%	100.00		%
Less: Net operating income attributable to noncontrolling interests in property partnerships	(24,879		)	—			(107,420		)	273			—			(132,026		)
Add: Company’s share of net operating income from unconsolidated joint ventures	2,096			27,222			5,065			—			20,415			54,798
Company’s share of net operating income	$	378,345		$	27,222		$	329,598		$	192,825		$	214,617		$	1,142,607
% of Grand Totals	33.11		%	2.38		%	28.85		%	16.88		%	18.78		%	100.00		%

_______________

(1)

Rental Revenue is equal to total Revenue per the Company’s Consolidated Statements of Operations, less Development and Management Services Revenue and Direct Reimbursements of Payroll and Related Costs from Management Services Contracts Revenue per the Consolidated Statements of Operations.

Subsequent Events	9 Months Ended
Subsequent Events	Sep. 30, 2019
Subsequent Events [Abstract]
Subsequent Events [Text Block]	13. Subsequent Events On October 1, 2019, a joint venture in which the Company has a 50% interest partially placed in-service Dock 72, a Class A office project with approximately 670,000 net rentable square feet located in Brooklyn, New York. On October 1, 2019, a joint venture in which the Company has a 50% interest partially placed in-service The Hub on Causeway - Residential, an approximately 320,000 square foot project comprised of 440 residential units located in Boston, Massachusetts. On October 24, 2019, the Company completed and placed in-service 145 Broadway, a build-to-suit Class A office project with approximately 485,000 net rentable square feet located in Cambridge, Massachusetts.

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	Boston Properties, Inc. does not have any other significant assets, liabilities or operations, other than its investment in Boston Properties Limited Partnership, nor does it have employees of its own. Boston Properties Limited Partnership, not Boston Properties, Inc., generally executes all significant business relationships other than transactions involving securities of Boston Properties, Inc. All majority-owned subsidiaries and joint ventures over which the Company has financial and operating control and variable interest entities (“VIEs”) in which the Company has determined it is the primary beneficiary are included in the consolidated financial statements. All significant intercompany balances and transactions have been eliminated in consolidation. The Company accounts for all other unconsolidated joint ventures using the equity method of accounting. Accordingly, the Company’s share of the earnings of these joint ventures and companies is included in consolidated net income. The accompanying interim financial statements are unaudited; however, the financial statements have been prepared in accordance with generally accepted accounting principles (“GAAP”) for interim financial information and in conjunction with the rules and regulations of the Securities and Exchange Commission. Accordingly, they do not include all of the disclosures required by GAAP for complete financial statements. In the opinion of management, all adjustments (consisting solely of normal recurring matters) necessary for a fair statement of the financial statements for these interim periods have been included. The results of operations for the interim periods are not necessarily indicative of the results to be obtained for other interim periods or for the full fiscal year. The year-end consolidated balance sheet data was derived from audited financial statements, but does not include all disclosure required by GAAP. These financial statements should be read in conjunction with the Company’s financial statements and notes thereto contained in the Company’s Annual Report in the Company’s Form 10-K for its fiscal year ended December 31, 2018.
Fair Value of Financial Instruments	The Company follows the authoritative guidance for fair value measurements when valuing its financial instruments for disclosure purposes. Boston Properties Limited Partnership determines the fair value of its unsecured senior notes using market prices. The inputs used in determining the fair value of Boston Properties Limited Partnership’s unsecured senior notes is categorized at a Level 1 basis (as defined in Accounting Standards Codification (“ASC”) 820 “Fair Value Measurements and Disclosures” (“ASC 820”)) due to the fact that it uses quoted market rates to value these instruments. However, the inputs used in determining the fair value could be categorized at a Level 2 basis (as defined in ASC 820) if trading volumes are low. The Company determines the fair value of its related party note receivable, note receivable and mortgage notes payable using discounted cash flow analysis by discounting the spread between the future contractual interest payments and hypothetical future interest payments on note receivables / mortgage debt based on current market rates for similar securities. In determining the current market rates, the Company adds its estimates of market spreads to the quoted yields on federal government treasury securities with similar maturity dates to its debt. The inputs used in determining the fair value of the Company’s related party note receivable, note receivable, and mortgage notes payable are categorized at a Level 3 basis (as defined in ASC 820) due to the fact that the Company considers the rates used in the valuation techniques to be unobservable inputs. To the extent that there are outstanding borrowings under the unsecured line of credit or unsecured term loan, the Company utilizes a discounted cash flow methodology in order to estimate the fair value. To the extent that credit spreads have changed since the origination, the net present value of the difference between future contractual interest payments and future interest payments based on the Company’s estimate of a current market rate would represent the difference between the book value and the fair value. The Company’s estimate of a current market rate is based upon the rate, considering current market conditions and Boston Properties Limited Partnership’s specific credit profile, at which it estimates it could obtain similar borrowings. To the extent there are outstanding borrowings, this current market rate is estimated and therefore would be primarily based upon a Level 3 input. Because the Company’s valuations of its financial instruments are based on these types of estimates, the actual fair values of its financial instruments may differ materially from those estimates. In addition, the Company’s estimated fair values for these instruments as of the end of the applicable reporting period are not projections of nor necessarily indicative of estimated or actual fair values in future reporting periods.
Variable Interest Entities (VIEs)	Consolidated VIEs are those for which the Company is considered to be the primary beneficiary of a VIE. The primary beneficiary is the entity that has a controlling financial interest in the VIE, which is defined by the entity having both of the following characteristics: (1) the power to direct the activities that, when taken together, most significantly impact the VIE’s performance and (2) the obligation to absorb losses or the right to receive the returns from the VIE that could potentially be significant to the VIE. The Company has determined that it is the primary beneficiary for six of the eight entities that are VIEs.
New Accounting Pronouncements	New Accounting Pronouncements Adopted Leases On January 1, 2019, the Company adopted Accounting Standards Update (“ASU”) 2016-02, “Leases (Topic 842)” (“ASU 2016-02” or “Topic 842”). For information pertaining to the Company’s adoption and disclosures with respect to leases, see Note 4. New Accounting Pronouncements Issued but not yet Adopted Financial Instruments - Credit Losses In June 2016, the Financial Accounting Standards Board (“FASB”) issued ASU 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” (“ASU 2016-13”). ASU 2016-13 is intended to provide financial statement users with more decision-useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date by replacing the current incurred loss impairment methodology with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. In November 2018, the FASB issued ASU 2018-19, “Codification Improvements to Topic 326, Financial Instruments - Credit Losses” (“ASU 2018-19”). ASU 2018-19 clarifies that receivables arising from operating leases are not within the scope of Accounting Standards Codification (“ASC”) 326-20, “Financial Instruments - Credit Losses - Measured at Amortized Cost,” which addresses financial assets measured at amortized cost basis, including net investments in leases arising from sales-type and direct financing leases. Instead, impairment of receivables arising from operating leases should be accounted for in accordance with ASC 842, “Leases” (“ASC 842”). ASU 2016-13 and ASU 2018-19 are effective for the Company for reporting periods beginning after December 15, 2019, with early adoption permitted. The Company will adopt ASU 2016-13 and ASU 2018-19 effective January 1, 2020 using the modified retrospective approach, which is expected to result in the Company recognizing on January 1, 2020 the cumulative effect of adopting ASU 2016-13 and ASU 2018-19 to certain of its financial instruments outstanding on January 1, 2020. The Company expects that (1) certain of its accounts receivable, except for amounts arising from operating leases accounted for under ASC 842, (2) its related party note receivable, (3) its note receivable and (4) certain of its financial guarantees may be impacted by the adoption of ASU 2016-13 and ASU 2018-19.

Leases (Policies)

9 Months Ended

Sep. 30, 2019

Accounting Policies [Abstract]

Lessee


•	The interpolated rates from yields on outstanding U.S. Treasury issuances for up to 30 years and for years 31 and beyond, longer-term publicly traded educational institution debt issued by high credit quality educational institutions with maturity dates up to 2116,


•	Observable mortgage rates spread over U.S. Treasury issuances, and


•	Unlevered property yields and discount rates.

The Company then applied adjustments to account for considerations related to term and interpolated the IBR.

Lessor

Basis Of Presentation And Summary Of Significant Accounting Policies (Tables)

9 Months Ended

Sep. 30, 2019

Accounting Policies [Abstract]

Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value

The following table presents the aggregate carrying value of the Company’s related party note receivable, note receivable, mortgage notes payable, net, unsecured senior notes, net, unsecured line of credit and unsecured term loan, net and the Company’s corresponding estimate of fair value as of September 30, 2019 and December 31, 2018 (in thousands):



	September 30, 2019				December 31, 2018
	Carrying Amount		Estimated Fair Value		Carrying Amount		Estimated Fair Value
Related party note receivable	$	80,000	$	81,337	$	80,000	$	80,000
Note receivable	19,844		18,507		19,468		19,468
	$	99,844	$	99,844	$	99,468	$	99,468

Mortgage notes payable, net	$	2,952,006	$	3,052,922	$	2,964,572	$	2,903,925
Unsecured senior notes, net	8,387,913		8,848,468		7,544,697		7,469,338
Unsecured line of credit	—		—		—		—
Unsecured term loan, net	498,819		500,618		498,488		500,783
Total	$	11,838,738	$	12,402,008	$	11,007,757	$	10,874,046

Real Estate (Tables)

9 Months Ended

Sep. 30, 2019

Schedule of Real Estate Properties [Table Text Block]

Boston Properties, Inc.

Real estate consisted of the following at September 30, 2019 and December 31, 2018 (in thousands):



	September 30, 2019			December 31, 2018
Land	$	5,087,029		$	5,072,568
Right of use assets - finance leases	237,394			—
Right of use assets - operating leases	149,231			—
Land held for future development (1)	246,972			200,498
Buildings and improvements	13,396,648			13,356,751
Tenant improvements	2,559,907			2,396,932
Furniture, fixtures and equipment	44,908			44,351
Construction in progress	953,336			578,796
Total	22,675,425			21,649,896
Less: Accumulated depreciation	(5,164,353		)	(4,897,777		)
	$	17,511,072		$	16,752,119

_______________

(1)

Includes pre-development costs.

Finance Lease, Liability, Maturity [Table Text Block]

The following table provides a maturity analysis for the Company’s lease liabilities related to its operating and finance leases as of September 30, 2019 (in thousands):



	Operating			Finance
October 1, 2019 - December 31, 2019	$	2,426		$	150
2020	10,050			907
2021	24,953			5,958
2022	18,041			10,208
2023	10,345			9,708
Thereafter (1)	567,232			1,431,760
Total lease payments	633,047			1,458,691
Less: interest portion	(433,292		)	(1,237,662		)
Present value of lease payments	$	199,755		$	221,029

_______________

(1)

Finance lease payments in 2024 include approximately $38.7 million related to a purchase option that the Company is reasonably certain it will exercise.

Schedule of Real Estate Properties [Table Text Block]

Boston Properties Limited Partnership

Real estate consisted of the following at September 30, 2019 and December 31, 2018 (in thousands):



	September 30, 2019			December 31, 2018
Land	$	4,986,576		$	4,971,475
Right of use assets - finance leases	237,394			—
Right of use assets - operating leases	149,231			—
Land held for future development (1)	246,972			200,498
Buildings and improvements	13,101,302			13,059,488
Tenant improvements	2,559,907			2,396,932
Furniture, fixtures and equipment	44,908			44,351
Construction in progress	953,336			578,796
Total	22,279,626			21,251,540
Less: Accumulated depreciation	(5,061,727		)	(4,800,475		)
	$	17,217,899		$	16,451,065

_______________

(1)

Includes pre-development costs.

Finance Lease, Liability, Maturity [Table Text Block]

As of January 24, 2019, the lease payments from the finance lease related to the remaining parcels made available for lease to the Company were as follows (in thousands):



Period from January 24, 2019 through December 31, 2019	$	17,918
2020	109,460
Total expected minimum lease payments	127,378
Interest portion	(4,815		)
Present value of expected net lease payments	$	122,563

2100 Pennsylvania Avenue [Member]

Finance Lease, Liability, Maturity [Table Text Block]

As of July 16, 2019, the lease payments from the finance lease were as follows (in thousands):



Period from July 16, 2019 through December 31, 2019	$	—
2020	—
2021	3,863
2022	8,576
2023	8,669
Thereafter	1,358,518
Total expected minimum lease payments	1,379,626
Interest portion	(1,214,649		)
Present value of expected net lease payments	$	164,977

Real Estate Asset Acquisition (Tables) - 880 & 890 Winter Street [Member]

Aug. 27, 2019

Schedule of Business Acquisitions, by Acquisition [Table Text Block]

The following table summarizes the allocation of the purchase price, including transaction costs, of 880 and 890 Winter Street at the date of acquisition (in thousands):



Land	$	31,376
Building and improvements	57,922
Tenant improvements	6,024
In-place lease intangibles	11,494
Above-market lease intangibles	246
Below-market lease intangibles	(1,092		)
Net assets acquired	$	105,970

Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]



	Acquired In-Place Lease Intangibles		Acquired Above-Market Lease Intangibles		Acquired Below- Market Lease Intangibles
Period from August 27, 2019 through December 31, 2019	$	1,801	$	28	$	(226	)
2020	4,485		80		(599		)
2021	2,391		80		(237		)
2022	1,121		43		(30		)
2023	179		15		—
2024	60		—		—

Leases (Tables)

9 Months Ended

Sep. 30, 2019

Leases [Abstract]

Lessee, Operating Lease, Liability, Maturity [Table Text Block]

The following table provides a maturity analysis for the Company’s lease liabilities related to its operating and finance leases as of September 30, 2019 (in thousands):



	Operating			Finance
October 1, 2019 - December 31, 2019	$	2,426		$	150
2020	10,050			907
2021	24,953			5,958
2022	18,041			10,208
2023	10,345			9,708
Thereafter (1)	567,232			1,431,760
Total lease payments	633,047			1,458,691
Less: interest portion	(433,292		)	(1,237,662		)
Present value of lease payments	$	199,755		$	221,029

Lease, Cost [Table Text Block]

The following table provides lease cost information for the Company’s operating and finance leases for the three and nine months ended September 30, 2019 (in thousands):



	Three months ended September 30, 2019		Nine months ended September 30, 2019
Lease costs
Operating lease costs	$	3,637	$	10,970
Finance lease costs
Amortization of right of use asset (1)	$	12	$	14
Interest on lease liabilities (2)	$	12	$	36

_______________


(1)	The finance leases relate to either land, buildings or assets that remain in development. For land leases classified as finance leases because of a purchase option that the Company views as an economic incentive, the Company follows its existing policy and does not depreciate land because it is assumed to


(2)	Three of the finance leases relate to assets under development and as such, the entire interest amount was capitalized.

The following table provides other quantitative information for the Company’s operating and finance leases as of September 30, 2019:



	September 30, 2019
Other information
Weighted-average remaining lease term (in years)
Operating leases	51
Finance leases	72
Weighted-average discount rate
Operating leases	5.7	%
Finance leases	6.2	%

Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]



Years Ending December 31,	(in thousands)
2019	$	11,425
2020	18,425
2021	25,310
2022	8,894
2023	9,084
Thereafter	567,232

Capital Leases in Financial Statements of Lessee Disclosure [Text Block]

The following table provides a maturity analysis for the Company's future minimum lease payments, as of December 31, 2018, related to the four capital leases, through 2036:



Years Ending December 31,	(in thousands)
2019	$	1,441
2020	12,682
2021	2,123
2022	1,253
2023	944
Thereafter	73,241
Total expected minimum lease payments	91,684
Interest portion	(27,497		)
Present value of expected net minimum lease payments	$	64,187

Finance Lease, Liability, Maturity [Table Text Block]

The following table provides a maturity analysis for the Company’s lease liabilities related to its operating and finance leases as of September 30, 2019 (in thousands):



	Operating			Finance
October 1, 2019 - December 31, 2019	$	2,426		$	150
2020	10,050			907
2021	24,953			5,958
2022	18,041			10,208
2023	10,345			9,708
Thereafter (1)	567,232			1,431,760
Total lease payments	633,047			1,458,691
Less: interest portion	(433,292		)	(1,237,662		)
Present value of lease payments	$	199,755		$	221,029

_______________

(1)

Finance lease payments in 2024 include approximately $38.7 million related to a purchase option that the Company is reasonably certain it will exercise.

Operating Lease, Lease Income [Table Text Block]



Lease Revenue	Three months ended September 30, 2019		Nine months ended September 30, 2019
Fixed contractual payments	$	566,294	$	1,678,100
Variable lease payments	125,931		373,565
	$	692,225	$	2,051,665

Lessor, Operating Lease, Payments to be Received, Maturity [Table Text Block]



Years Ending December 31,	(in thousands)
2019	$	2,088,171
2020	2,106,963
2021	2,015,031
2022	1,838,699
2023	1,736,636
Thereafter	12,295,464



	(in thousands)
October 1, 2019 - December 31, 2019	$	530,470
2020	2,196,428
2021	2,177,016
2022	2,050,537
2023	1,980,918
Thereafter	15,447,131

Investments in Unconsolidated Joint Ventures (Tables)

9 Months Ended

Sep. 30, 2019

Investments In Unconsolidated Joint Ventures [Abstract]

Investments In Unconsolidated Joint Ventures

The investments in unconsolidated joint ventures consist of the following at September 30, 2019 and December 31, 2018:



		Nominal % Ownership			Carrying Value of Investment (1)
Entity	Properties	Nominal % Ownership			September 30, 2019			December 31, 2018
					(in thousands)
Square 407 Limited Partnership	Market Square North	50.0	%		$	(5,114	)	$	(6,424	)
BP/CRF Metropolitan Square, LLC	Metropolitan Square	20.0	%		5,726			2,644
901 New York, LLC	901 New York Avenue	25.0	%	(2)	(12,385		)	(13,640		)
WP Project Developer LLC	Wisconsin Place Land and Infrastructure	33.3	%	(3)	37,179			38,214
Annapolis Junction NFM LLC	Annapolis Junction	50.0	%	(4)	25,314			25,268
540 Madison Venture LLC	540 Madison Avenue	60.0	%	(5)	3,075			66,391
500 North Capitol Venture LLC	500 North Capitol Street, NW	30.0	%		(5,661		)	(5,026		)
501 K Street LLC	1001 6th Street	50.0	%	(6)	42,555			42,557
Podium Developer LLC	The Hub on Causeway - Podium	50.0	%		41,434			69,302
Residential Tower Developer LLC	The Hub on Causeway - Residential	50.0	%		48,491			47,505
Hotel Tower Developer LLC	The Hub on Causeway - Hotel Air Rights	50.0	%		3,917			3,022
Office Tower Developer LLC	100 Causeway Street	50.0	%		74,083			23,804
1265 Main Office JV LLC	1265 Main Street	50.0	%		3,932			3,918
BNY Tower Holdings LLC	Dock 72	50.0	%		94,700			82,520
CA-Colorado Center Limited Partnership	Colorado Center	50.0	%		250,213			253,495
7750 Wisconsin Avenue LLC	7750 Wisconsin Avenue	50.0	%		55,662			69,724
BP-M 3HB Venture LLC	3 Hudson Boulevard	25.0	%		54,037			46,993
SMBP Venture LP	Santa Monica Business Park	55.0	%		163,809			180,952
Platform 16 Holdings LP	Platform 16	55.0	%	(7)	29,128			—
					$	910,095		$	931,219

_______________


(1)	Investments with deficit balances aggregating approximately $23.2 million and $25.1 million at September 30, 2019 and December 31, 2018, respectively, have been reflected within Other Liabilities in the Company’s Consolidated Balance Sheets.


(2)	The Company’s economic ownership has increased based on the achievement of certain return thresholds.


(3)	The Company’s wholly-owned subsidiary that owns Wisconsin Place Office also owns a 33.3% interest in the joint venture entity that owns the land, parking garage and infrastructure of the project.


(4)	The joint venture owns three in-service buildings and two undeveloped land parcels.


(5)	The property was sold on June 27, 2019. As of September 30, 2019, the investment is comprised of undistributed cash. See note below for additional details.


(6)	Under the joint venture agreement for this land parcel, the partner will be entitled to up to two additional payments from the venture based on increases in total entitled square footage of the project above 520,000 square feet and achieving certain project returns at stabilization.


(7)	This entity is a VIE (See Note 2).

Schedule Of Balance Sheets Of The Unconsolidated Joint Ventures [Text Block]

The combined summarized balance sheets of the Company’s unconsolidated joint ventures are as follows:



	September 30, 2019		December 31, 2018
	(in thousands)
ASSETS
Real estate and development in process, net (1)	$	3,782,279	$	3,545,906
Other assets	498,040		543,512
Total assets	$	4,280,319	$	4,089,418
LIABILITIES AND MEMBERS’/PARTNERS’ EQUITY
Mortgage and notes payable, net	$	2,107,805	$	2,017,609
Other liabilities (2)	773,033		582,006
Members’/Partners’ equity	1,399,481		1,489,803
Total liabilities and members’/partners’ equity	$	4,280,319	$	4,089,418
Company’s share of equity	$	569,704	$	622,498
Basis differentials (3)	340,391		308,721
Carrying value of the Company’s investments in unconsolidated joint ventures (4)	$	910,095	$	931,219

_______________


(1)	At September 30, 2019, this amount includes right of use assets - finance leases and right of use assets - operating leases totaling approximately $383.9 million and $12.3 million, respectively.


(2)	At September 30, 2019, this amount includes lease liabilities - finance leases and lease liabilities - operating leases totaling approximately $511.7 million and $17.3 million, respectively.

(3)

(4)

Investments with deficit balances aggregating approximately $23.2 million and $25.1 million at September 30, 2019 and December 31, 2018, respectively, have been reflected within Other Liabilities in the Company’s Consolidated Balance Sheets.

Statements Of Operations Of The Joint Ventures

The combined summarized statements of operations of the Company’s unconsolidated joint ventures are as follows:



	Three months ended September 30,						Nine months ended September 30,
	2019			2018			2019			2018
	(in thousands)
Total revenue (1)	$	75,940		$	76,177		$	239,099		$	189,759
Expenses
Operating	28,839			29,522			89,472			75,239
Depreciation and amortization	23,477			44,993			76,941			74,245
Total expenses	52,316			74,515			166,413			149,484
Other income (expense)
Interest expense	(20,483		)	(19,861		)	(62,043		)	(48,993		)
Gain on sale of real estate (2)	(812		)	—			33,760			—
Net income (loss)	$	2,329		$	(18,199	)	$	44,403		$	(8,718	)

Company’s share of net income (loss)	$	392		$	(2,858	)	$	24,352		$	1,073
Basis differential (2) (3)	(1,041		)	(1,455		)	23,176			(4,156		)
Income (loss) from unconsolidated joint ventures	$	(649	)	$	(4,313	)	$	47,528		$	(3,083	)

_______________


(1)	Includes straight-line rent adjustments of approximately $5.3 million and $4.8 million for the three months ended September 30, 2019 and 2018, respectively, and $18.7 million and $9.8 million for the nine months ended September 30, 2019 and 2018, respectively.

(2)

(3)

Unsecured Senior Notes (Tables)

9 Months Ended

Sep. 30, 2019

Debt Disclosure [Abstract]

Schedule of Unsecured Senior Notes

The following summarizes the unsecured senior notes outstanding as of September 30, 2019 (dollars in thousands):



	Coupon/Stated Rate		Effective Rate(1)		Principal Amount			Maturity Date(2)
10 Year Unsecured Senior Notes	4.125	%	4.289	%	$	850,000		May 15, 2021
11 Year Unsecured Senior Notes	3.850	%	3.954	%	1,000,000			February 1, 2023
10.5 Year Unsecured Senior Notes	3.125	%	3.279	%	500,000			September 1, 2023
10.5 Year Unsecured Senior Notes	3.800	%	3.916	%	700,000			February 1, 2024
7 Year Unsecured Senior Notes	3.200	%	3.350	%	850,000			January 15, 2025
10 Year Unsecured Senior Notes	3.650	%	3.766	%	1,000,000			February 1, 2026
10 Year Unsecured Senior Notes	2.750	%	3.495	%	1,000,000			October 1, 2026
10 Year Unsecured Senior Notes	4.500	%	4.628	%	1,000,000			December 1, 2028
10 Year Unsecured Senior Notes	3.400	%	3.505	%	850,000			June 21, 2029
10.5 Year Unsecured Senior Notes	2.900	%	2.984	%	700,000			March 15, 2030
Total principal					8,450,000
Net unamortized discount					(18,232		)
Deferred financing costs, net					(43,855		)
Total					$	8,387,913

_______________


(1)	Yield on issuance date including the effects of discounts on the notes, settlements of interest rate contracts and the amortization of financing costs.

(2)

No principal amounts are due prior to maturity.

- Definition

Tabular disclosure of long-debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. These are debt arrangements that originally required repayment more than twelve months after issuance or greater than the normal operating cycle of the entity, if longer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28541-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21506-112644

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(e),(f))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
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-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21521-112644

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21538-112644

Reference 8: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

Reference 9: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 10: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

+ Details

Noncontrolling Interests (Tables)

9 Months Ended

Sep. 30, 2019

Noncontrolling Interest [Line Items]

Distributions Declared to OP, LTIP, OPP and MYLTIP Units [Table Text Block]



Record Date	Payment Date	Dividend (Per Share)		Distribution (Per Unit)
September 30, 2019	October 31, 2019		$0.95		$0.95
June 28, 2019	July 31, 2019		$0.95		$0.95
March 29, 2019	April 30, 2019		$0.95		$0.95
December 31, 2018	January 30, 2019		$0.95		$0.95

September 28, 2018	October 31, 2018		$0.95		$0.95
June 29, 2018	July 31, 2018		$0.80		$0.80
March 29, 2018	April 30, 2018		$0.80		$0.80
December 31, 2017	January 30, 2018		$0.80		$0.80

Noncontrolling Interests [Member]

Noncontrolling Interest [Line Items]

Distributions Declared to OP, LTIP, OPP and MYLTIP Units [Table Text Block]



Record Date	Payment Date	Distributions per OP Unit and LTIP Unit		Distributions per MYLTIP Unit
September 30, 2019	October 31, 2019		$0.95		$0.095
June 28, 2019	July 31, 2019		$0.95		$0.095
March 29, 2019	April 30, 2019		$0.95		$0.095
December 31, 2018	January 30, 2019		$0.95		$0.095

The following table presents Boston Properties Limited Partnership’s distributions on the OP Units and LTIP Units (including the 2012 OPP Units, 2013 MYLTIP Units, 2014 MYLTIP Units and, after the February 4, 2018 measurement date, the 2015 MYLTIP Units) and its distributions on the 2015 MYLTIP Units (prior to the February 4, 2018 measurement date), 2016 MYLTIP Units, 2017 MYLTIP Units and 2018 MYLTIP Units (after the February 6, 2018 issuance date) that occurred during the nine months ended September 30, 2018:



Record Date	Payment Date	Distributions per OP Unit and LTIP Unit		Distributions per MYLTIP Unit
September 28, 2018	October 31, 2018		$0.95		$0.095
June 29, 2018	July 31, 2018		$0.80		$0.080
March 29, 2018	April 30, 2018		$0.80		$0.080
December 31, 2017	January 30, 2018		$0.80		$0.080

Stockholders' Equity / Partners' Capital Tables (Tables)

9 Months Ended

Sep. 30, 2019

Class of Stock [Line Items]

Dividends Declared [Table Text Block]



Record Date	Payment Date	Dividend (Per Share)		Distribution (Per Unit)
September 30, 2019	October 31, 2019		$0.95		$0.95
June 28, 2019	July 31, 2019		$0.95		$0.95
March 29, 2019	April 30, 2019		$0.95		$0.95
December 31, 2018	January 30, 2019		$0.95		$0.95

September 28, 2018	October 31, 2018		$0.95		$0.95
June 29, 2018	July 31, 2018		$0.80		$0.80
March 29, 2018	April 30, 2018		$0.80		$0.80
December 31, 2017	January 30, 2018		$0.80		$0.80

Series B Cumulative Redeemable Preferred Stock [Member]

Class of Stock [Line Items]

Dividends Declared [Table Text Block]



Record Date	Payment Date	Dividend (Per Share)
November 1, 2019	November 15, 2019		$32.8125
August 2, 2019	August 15, 2019		$32.8125
May 3, 2019	May 15, 2019		$32.8125
February 4, 2019	February 15, 2019		$32.8125

November 2, 2018	November 15, 2018		$32.8125
August 3, 2018	August 15, 2018		$32.8125
May 4, 2018	May 15, 2018		$32.8125
February 2, 2018	February 15, 2018		$32.8125

Earnings Per Share / Common Unit (Tables)

9 Months Ended

Sep. 30, 2019

Computation Of Basic And Diluted Earnings Per Share



	Three months ended September 30, 2019
	Income (Numerator)		Shares (Denominator)	Per Share Amount
	(in thousands, except for per share amounts)
Basic Earnings:
Net income attributable to Boston Properties, Inc. common shareholders	$	107,771	154,577	$	0.70
Effect of Dilutive Securities:
Stock Based Compensation	—		243	—
Diluted Earnings:
Net income attributable to Boston Properties, Inc. common shareholders	$	107,771	154,820	$	0.70

	Three months ended September 30, 2018
	Income (Numerator)		Shares (Denominator)	Per Share Amount
	(in thousands, except for per share amounts)
Basic Earnings:
Net income attributable to Boston Properties, Inc. common shareholders	$	119,118	154,440	$	0.77
Effect of Dilutive Securities:
Stock Based Compensation	—		238	—
Diluted Earnings:
Net income attributable to Boston Properties, Inc. common shareholders	$	119,118	154,678	$	0.77

	Nine months ended September 30, 2019
	Income (Numerator)		Shares (Denominator)	Per Share Amount
	(in thousands, except for per share amounts)
Basic Earnings:
Net income attributable to Boston Properties, Inc. common shareholders	$	370,200	154,553	$	2.40
Effect of Dilutive Securities:
Stock Based Compensation	—		294	(0.01		)
Diluted Earnings:
Net income attributable to Boston Properties, Inc. common shareholders	$	370,200	154,847	$	2.39



	Nine months ended September 30, 2018
	Income (Numerator)			Shares (Denominator)	Per Share Amount
	(in thousands, except for per share amounts)
Basic Earnings:
Net income attributable to Boston Properties, Inc. common shareholders	$	423,835		154,414	$	2.74
Allocation of undistributed earnings to participating securities	(87		)	—	—
Net income attributable to Boston Properties, Inc. common shareholders	$	423,748		154,414	$	2.74
Effect of Dilutive Securities:
Stock Based Compensation	—			238	—
Diluted Earnings:
Net income attributable to Boston Properties, Inc. common shareholders	$	423,748		154,652	$	2.74

Computation Of Basic And Diluted Earnings Per Share



	Three months ended September 30, 2019
	Income (Numerator)		Units (Denominator)	Per Unit Amount
	(in thousands, except for per unit amounts)
Basic Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	122,117	172,215	$	0.71
Effect of Dilutive Securities:
Stock Based Compensation	—		243	—
Diluted Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	122,117	172,458	$	0.71



	Three months ended September 30, 2018
	Income (Numerator)			Units (Denominator)	Per Unit Amount
	(in thousands, except for per unit amounts)
Basic Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	136,201		171,928	$	0.79
Effect of Dilutive Securities:
Stock Based Compensation	—			238	—
Diluted Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	136,201		172,166	$	0.79

	Nine months ended September 30, 2019
	Income (Numerator)			Units (Denominator)	Per Unit Amount
	(in thousands, except for per unit amounts)
Basic Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	421,214		172,183	$	2.45
Effect of Dilutive Securities:
Stock Based Compensation	—			294	(0.01		)
Diluted Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	421,214		172,477	$	2.44

	Nine months ended September 30, 2018
	Income (Numerator)			Units (Denominator)	Per Unit Amount
	(in thousands, except for per unit amounts)
Basic Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	483,069		171,904	$	2.81
Allocation of undistributed earnings to participating securities	(97		)	—	—
Net income attributable to Boston Properties Limited Partnership common unitholders	$	482,972		171,904	$	2.81
Effect of Dilutive Securities:
Stock Based Compensation	—			238	—
Diluted Earnings:
Net income attributable to Boston Properties Limited Partnership common unitholders	$	482,972		172,142	$	2.81

Segment Information (Tables)

9 Months Ended

Sep. 30, 2019

Segment Reporting [Abstract]

Schedule Of Reconciliation Of Net Operating Income To Net Income

Boston Properties, Inc.



	Three months ended September 30,						Nine months ended September 30,
	2019			2018			2019		2018
	(in thousands)
Net income attributable to Boston Properties, Inc. common shareholders	$	107,771		$	119,118		$	370,200	$	423,835
Add:
Preferred dividends	2,625			2,625			7,875		7,875
Noncontrolling interest—common units of Boston Properties Limited Partnership	12,504			13,852			43,133		49,128
Noncontrolling interests in property partnerships	18,470			14,850			54,782		46,484
Interest expense	106,471			95,366			309,837		277,790
Loss from early extinguishment of debt	28,010			—			28,010		—
Impairment loss	—			—			24,038		—
Net operating income from unconsolidated joint ventures	23,065			22,511			73,129		54,798
Depreciation and amortization expense	165,862			157,996			507,867		480,210
Transaction costs	538			914			1,415		1,409
Payroll and related costs from management services contracts	2,429			2,516			8,227		7,371
General and administrative expense	31,147			29,677			107,980		94,039
Less:
Net operating income attributable to noncontrolling interests in property partnerships	46,249			43,068			138,896		132,026
Gains from investments in securities	106			1,075			4,240		1,454
Interest and other income	7,178			2,822			14,546		7,049
Gains (losses) on sales of real estate	(15		)	7,863			766		122,552
Income (loss) from unconsolidated joint ventures	(649		)	(4,313		)	47,528		(3,083		)
Direct reimbursements of payroll and related costs from management services contracts	2,429			2,516			8,227		7,371
Development and management services revenue	10,303			15,253			29,566		32,963
Company’s share of Net Operating Income	$	433,291		$	391,141		$	1,292,724	$	1,142,607

Boston Properties Limited Partnership



	Three months ended September 30,						Nine months ended September 30,
	2019			2018			2019		2018
	(in thousands)
Net income attributable to Boston Properties Limited Partnership common unitholders	$	122,117		$	136,201		$	421,214	$	483,069
Add:
Preferred distributions	2,625			2,625			7,875		7,875
Noncontrolling interests in property partnerships	18,470			14,850			54,782		46,484
Interest expense	106,471			95,366			309,837		277,790
Loss from early extinguishment of debt	28,010			—			28,010		—
Impairment loss	—			—			22,272		—
Net operating income from unconsolidated joint ventures	23,065			22,511			73,129		54,798
Depreciation and amortization expense	164,020			156,056			501,901		474,383
Transaction costs	538			914			1,415		1,409
Payroll and related costs from management services contracts	2,429			2,516			8,227		7,371
General and administrative expense	31,147			29,677			107,980		94,039
Less:
Net operating income attributable to noncontrolling interests in property partnerships	46,249			43,068			138,896		132,026
Gains from investments in securities	106			1,075			4,240		1,454
Interest and other income	7,178			2,822			14,546		7,049
Gains (losses) on sales of real estate	(15		)	9,154			915		126,831
Income (loss) from unconsolidated joint ventures	(649		)	(4,313		)	47,528		(3,083		)
Direct reimbursements of payroll and related costs from management services contracts	2,429			2,516			8,227		7,371
Development and management services revenue	10,303			15,253			29,566		32,963
Company’s share of Net Operating Income	$	433,291		$	391,141		$	1,292,724	$	1,142,607

Schedule Of Segment Information By Geographic Area And Property Type

Information by geographic area (dollars in thousands):

For the three months ended September 30, 2019:



	Boston			Los Angeles			New York			San Francisco			Washington, DC			Total
Rental Revenue: (1)
Office	$	224,345		$	—		$	251,806		$	136,290		$	95,370		$	707,811
Residential	3,809			—			—			—			6,187			9,996
Hotel	13,014			—			—			—			—			13,014
Total	241,168			—			251,806			136,290			101,557			730,821
% of Grand Totals	33.00		%	—		%	34.45		%	18.65		%	13.90		%	100.00		%
Rental Expenses:
Office	81,278			—			98,698			45,900			35,716			261,592
Residential	1,244			—			—			—			2,767			4,011
Hotel	8,743			—			—			—			—			8,743
Total	91,265			—			98,698			45,900			38,483			274,346
% of Grand Totals	33.27		%	—		%	35.97		%	16.73		%	14.03		%	100.00		%
Net operating income	$	149,903		$	—		$	153,108		$	90,390		$	63,074		$	456,475
% of Grand Totals	32.84		%	—		%	33.54		%	19.80		%	13.82		%	100.00		%
Less: Net operating income attributable to noncontrolling interests in property partnerships	(10,379		)	—			(35,870		)	—			—			(46,249		)
Add: Company’s share of net operating income from unconsolidated joint ventures	1,686			14,702			(27		)	—			6,704			23,065
Company’s share of net operating income	$	141,210		$	14,702		$	117,211		$	90,390		$	69,778		$	433,291
% of Grand Totals	32.60		%	3.39		%	27.05		%	20.86		%	16.10		%	100.00		%

_______________


(1)	Rental Revenue is equal to Total Revenue per the Company’s Consolidated Statements of Operations, less Development and Management Services Revenue and Direct Reimbursements of Payroll and Related Costs from Management Services Contracts Revenue per the Consolidated Statements of Operations.

For the three months ended September 30, 2018:



	Boston			Los Angeles			New York			San Francisco			Washington, DC			Total
Rental Revenue: (1)
Office	$	210,277		$	—		$	237,944		$	102,035		$	98,275		$	648,531
Residential	1,905			—			—			—			4,415			6,320
Hotel	13,664			—			—			—			—			13,664
Total	225,846			—			237,944			102,035			102,690			668,515
% of Grand Totals	33.78		%	—		%	35.60		%	15.26		%	15.36		%	100.00		%
Rental Expenses:
Office	78,089			—			96,795			34,016			35,365			244,265
Residential	1,159			—			—			—			2,565			3,724
Hotel	8,828			—			—			—			—			8,828
Total	88,076			—			96,795			34,016			37,930			256,817
% of Grand Totals	34.30		%	—		%	37.68		%	13.25		%	14.77		%	100.00		%
Net operating income	$	137,770		$	—		$	141,149		$	68,019		$	64,760		$	411,698
% of Grand Totals	33.46		%	—		%	34.29		%	16.52		%	15.73		%	100.00		%
Less: Net operating income attributable to noncontrolling interests in property partnerships	(8,332		)	—			(34,723		)	(13		)	—			(43,068		)
Add: Company’s share of net operating income from unconsolidated joint ventures	781			13,246			1,698			—			6,786			22,511
Company’s share of net operating income	$	130,219		$	13,246		$	108,124		$	68,006		$	71,546		$	391,141
% of Grand Totals	33.29		%	3.39		%	27.64		%	17.39		%	18.29		%	100.00		%

_______________


(1)	Rental Revenue is equal to Total Revenue per the Company’s Consolidated Statements of Operations, less Development and Management Services Revenue and Direct Reimbursements of Payroll and Related Costs from Management Services Contracts Revenue per the Consolidated Statements of Operations.

For the nine months ended September 30, 2019:



	Boston			Los Angeles			New York			San Francisco			Washington, DC			Total
Rental Revenue: (1)
Office	$	659,717		$	—		$	761,993		$	391,851		$	288,201		$	2,101,762
Residential	9,732			—			—			—			16,978			26,710
Hotel	36,796			—			—			—			—			36,796
Total	706,245			—			761,993			391,851			305,179			2,165,268
% of Grand Totals	32.62		%	—		%	35.19		%	18.10		%	14.09		%	100.00		%
Rental Expenses:
Office	238,438			—			292,478			130,733			107,535			769,184
Residential	3,729			—			—			—			8,178			11,907
Hotel	25,686			—			—			—			—			25,686
Total	267,853			—			292,478			130,733			115,713			806,777
% of Grand Totals	33.20		%	—		%	36.26		%	16.20		%	14.34		%	100.00		%
Net operating income	$	438,392		$	—		$	469,515		$	261,118		$	189,466		$	1,358,491
% of Grand Totals	32.27		%	—		%	34.56		%	19.22		%	13.95		%	100.00		%
Less: Net operating income attributable to noncontrolling interests in property partnerships	(29,783		)	—			(108,665		)	(448		)	—			(138,896		)
Add: Company’s share of net operating income from unconsolidated joint ventures	3,276			45,864			3,455			—			20,534			73,129
Company’s share of net operating income	$	411,885		$	45,864		$	364,305		$	260,670		$	210,000		$	1,292,724
% of Grand Totals	31.87		%	3.55		%	28.18		%	20.16		%	16.24		%	100.00		%

_______________


(1)	Rental Revenue is equal to total Revenue per the Company’s Consolidated Statements of Operations, less Development and Management Services Revenue and Direct Reimbursements of Payroll and Related Costs from Management Services Contracts Revenue per the Consolidated Statements of Operations.

For the nine months ended September 30, 2018:



	Boston			Los Angeles			New York			San Francisco			Washington, DC			Total
Rental Revenue: (1)
Office	$	623,084		$	—		$	714,348		$	285,410		$	296,092		$	1,918,934
Residential	4,252			—			—			—			11,026			15,278
Hotel	37,373			—			—			—			—			37,373
Total	664,709			—			714,348			285,410			307,118			1,971,585
% of Grand Totals	33.71		%	—		%	36.23		%	14.48		%	15.58		%	100.00		%
Rental Expenses:
Office	235,560			—			282,395			92,858			106,386			717,199
Residential	2,379			—			—			—			6,530			8,909
Hotel	25,642			—			—			—			—			25,642
Total	263,581			—			282,395			92,858			112,916			751,750
% of Grand Totals	35.06		%	—		%	37.57		%	12.35		%	15.02		%	100.00		%
Net operating income	$	401,128		$	—		$	431,953		$	192,552		$	194,202		$	1,219,835
% of Grand Totals	32.88		%	—		%	35.41		%	15.79		%	15.92		%	100.00		%
Less: Net operating income attributable to noncontrolling interests in property partnerships	(24,879		)	—			(107,420		)	273			—			(132,026		)
Add: Company’s share of net operating income from unconsolidated joint ventures	2,096			27,222			5,065			—			20,415			54,798
Company’s share of net operating income	$	378,345		$	27,222		$	329,598		$	192,825		$	214,617		$	1,142,607
% of Grand Totals	33.11		%	2.38		%	28.85		%	16.88		%	18.78		%	100.00		%

_______________

(1)

Organization (Details) ft² in Millions	9 Months Ended	12 Months Ended
Organization (Details) ft² in Millions	Sep. 30, 2019 ft² Real_Estate_Properties series Buildings yr shares	Dec. 31, 2018 shares
Real Estate Properties [Line Items]
General and limited partnership interest in the operating partnership (percent)	89.60%	89.70%
Restriction on redemption of OP units from date of issuance (years) \| yr	1
One OP unit is equivalent to one share of Common Stock (in shares) \| shares	1
OP unit conversion rate (in shares) \| shares	1
Number Of Series Of Preferred Units Outstanding \| series	1
Office Properties Under Construction [Member]
Real Estate Properties [Line Items]
Number of real estate properties	11
Commercial Real Estate Properties [Member]
Real Estate Properties [Line Items]
Number of real estate properties	196
Net Rentable Area (in sf) \| ft²	51.9
Total Properties Under Construction [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	13
Net Rentable Area (in sf) \| ft²	6.3
Total Office Properties [Member]
Real Estate Properties [Line Items]
Number of real estate properties	177
Residential Properties [Member]
Real Estate Properties [Line Items]
Number of real estate properties	6
Residential Properties Under Construction [Member]
Real Estate Properties [Line Items]
Number of real estate properties	2
Retail Properties [ Member]
Real Estate Properties [Line Items]
Number of real estate properties \| Buildings	12
Hotel Property [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	1
Series B Cumulative Redeemable Preferred Stock [Member]
Real Estate Properties [Line Items]
Ratio of depository shares to shares of Series B Preferred Stock	0.01
Series B, Shares Outstanding (in shares) \| shares	80,000	80,000
Series B, Dividend Rate, Percentage	5.25%
Depository shares of Series B Cumulative Redeemable Preferred [Member]
Real Estate Properties [Line Items]
Series B, Shares Outstanding (in shares) \| shares	8,000,000
Series B Preferred Units [Member]
Real Estate Properties [Line Items]
Series B, Shares Outstanding (in shares) \| shares	80,000

Basis Of Presentation And Summary Of Significant Accounting Policies (Carrying Value Of Note Receivable, Indebtedness And Corresponding Estimate Of Fair Value) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable	$ 80,000	$ 80,000
Note receivable	19,844	19,468
Mortgage notes payable, net	2,952,006	2,964,572
Unsecured senior notes, net	8,387,913	7,544,697
Unsecured line of credit	0	0
Unsecured term loan, net	498,819	498,488
Carrying Amount [Member]
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable	80,000	80,000
Note receivable	19,844	19,468
Note and Related Party Receivables	99,844	99,468
Mortgage notes payable, net	2,952,006	2,964,572
Unsecured senior notes, net	8,387,913	7,544,697
Unsecured line of credit	0	0
Unsecured term loan, net	498,819	498,488
Total	11,838,738	11,007,757
Estimated Fair Value [Member]
Summary Of Significant Accounting Policies [Line Items]
Related party note receivable	81,337	80,000
Note receivable	18,507	19,468
Note and Related Party Receivables	99,844	99,468
Mortgage notes payable, net	3,052,922	2,903,925
Unsecured senior notes, net	8,848,468	7,469,338
Unsecured line of credit	0	0
Unsecured term loan, net	500,618	500,783
Total	$ 12,402,008	$ 10,874,046

Basis Of Presentation And Summary Of Significant Accounting Policies Narrative (Details) $ in Thousands	3 Months Ended
	Sep. 30, 2019 USD ($)	Dec. 31, 2018 USD ($)
Schedule of Equity Method Investments [Line Items]
Number of VIEs that are consolidated	6
Redeemable deferred stock units—54,610 units outstanding at redemption value at September 30, 2019	$ 7,081	$ 0
Accounts payable and accrued expenses	$ 421,269	276,645
In-service Properties [Member]
Schedule of Equity Method Investments [Line Items]
Number of VIEs that are consolidated	5
Boston Properties Limited Partnership
Schedule of Equity Method Investments [Line Items]
Redeemable deferred stock units—54,610 units outstanding at redemption value at September 30, 2019	$ 7,081	0
Accounts payable and accrued expenses	421,269	$ 276,645
Deferred Compensation for Directors [Member]
Schedule of Equity Method Investments [Line Items]
Change in classification of director deferred compensation plan	7,900
Redeemable deferred stock units—54,610 units outstanding at redemption value at September 30, 2019	7,300
Accounts payable and accrued expenses	600
Deferred Compensation for Directors [Member] \| Boston Properties Limited Partnership
Schedule of Equity Method Investments [Line Items]
Change in classification of director deferred compensation plan	7,900
Redeemable deferred stock units—54,610 units outstanding at redemption value at September 30, 2019	7,300
Accounts payable and accrued expenses	$ 600

Real Estate Properties Table (Details) - USD ($)
$ in Thousands

Sep. 30, 2019

Jan. 01, 2019

Dec. 31, 2018

Land

$ 5,087,029

$ 5,072,568

237,394

Land held for future development

149,231

$ 151,800

^[1]

246,972

200,498

Buildings and improvements

13,396,648

13,356,751

Tenant improvements

2,559,907

2,396,932

Furniture, fixtures and equipment

44,908

44,351

Construction in progress

953,336

578,796

22,675,425

21,649,896

Accumulated depreciation

(5,164,353)

(4,897,777)

Total real estate

17,511,072

16,752,119

Land

4,986,576

4,971,475

237,394

Land held for future development

149,231

^[1]

246,972

200,498

Buildings and improvements

13,101,302

13,059,488

Tenant improvements

2,559,907

2,396,932

Furniture, fixtures and equipment

44,908

44,351

Construction in progress

953,336

578,796

22,279,626

21,251,540

Accumulated depreciation

(5,061,727)

(4,800,475)

Total real estate

$ 17,217,899

$ 16,451,065

[1]	Includes pre-development costs.

Real Estate Narrative (Details)
$ in Thousands

1 Months Ended

2 Months Ended

3 Months Ended

5 Months Ended

6 Months Ended

9 Months Ended

12 Months Ended

Sep. 20, 2019

USD ($)

ft²

Jul. 16, 2019

USD ($)

ft²

Jun. 28, 2019

USD ($)

ft²

Jun. 03, 2019

USD ($)

May 09, 2019

USD ($)

ft²

Jan. 24, 2019

USD ($)

ft²

Sep. 30, 2019

USD ($)

ft²

Jan. 23, 2019

USD ($)

Jun. 02, 2019

USD ($)

Sep. 30, 2019

USD ($)

ft²

Jun. 27, 2019

USD ($)

Sep. 30, 2018

USD ($)

Jun. 02, 2019

USD ($)

Jun. 27, 2019

USD ($)

Sep. 30, 2019

USD ($)

ft²

Sep. 30, 2018

USD ($)

Dec. 31, 2018

USD ($)

Aug. 27, 2019

USD ($)

ft²

Real_Estate_Properties

Jul. 19, 2019

USD ($)

Jun. 01, 2019

ft²

Apr. 18, 2019

USD ($)

ft²

Jan. 10, 2019

USD ($)

ft²

Revenues

$ 743,553

$ 686,284

$ 2,203,061

$ 2,011,919

65,499

314,075

165,862

157,996

507,867

480,210

$ 237,394

237,394

221,029

83,486

175,577

(15)

7,863

766

122,552

Revenues

743,553

686,284

2,203,061

2,011,919

65,499

314,075

164,020

156,056

501,901

474,383

237,394

$ 221,029

221,029

83,486

175,577

$ (15)

9,154

$ 915

126,831

325 Main Street [Member]

Term of Lease Signed (in years)

15-year

115,000

325 Main Street [Member] | Boston Properties Limited Partnership

$ 9,900

$ 9,500

20 CityPoint [Member]

211,000

200 West Street [Member]

261,000

Finance Lease fixed purchase price

1,100,000

$ 134,800

122,600

$ 122,563

2100 Pennsylvania Avenue [Member]

65 years

Area of Land | a

5.6

Term of Lease Signed (in years)

16-year

470,000

Prepaid Rent

$ 15,000

185,100

Finance lease - right of use asset -prepaid rent

165,000

$ 164,977

15,000

Finance lease - right of use asset - initial direct costs

$ 5,100

Lesse, finance lease, term of amortization

75 years

Square Footage Of Signed Lease | ft²

75 years

300,000

Carnegie Center [Member]

880 & 890 Winter Street [Member]

1,700,000

Aggregate purchase price

$ 51,500

Deferred purchase price

$ 8,600

Revenues

$ 1,300

Number of real estate properties | Real_Estate_Properties

392,000

Aggregate purchase price

$ 106,000

164 Lexington Road [Member]

$ (200)

64,000

Gross Sale Price

$ 4,000

3,800

$ (100)

(50)

$ (100)

(200)

164 Lexington Road [Member] | Boston Properties Limited Partnership

2,500

2600 Tower Oaks Boulevard [Member]

$ 2,600

179,000

Gross Sale Price

$ 22,700

$ 21,400

$ (200)

(200)

(500)

$ (600)

2600 Tower Oaks Boulevard [Member] | Boston Properties Limited Partnership

$ 3,100

One Tower Center [Member]

$ 1,500

410,000

Gross Sale Price

$ 38,000

$ 36,600

$ (100)

$ (700)

$ (900)

$ (2,000)

$ (800)

One Tower Center [Member] | Boston Properties Limited Partnership

24,000

Future Office Building [Member] | 325 Main Street [Member]

$ 22,300

Square Footage Of Signed Lease | ft²

420,000

379,000

Future Retail Building [Member] | 325 Main Street [Member]

Office Properties Under Construction [Member] | 200 West Street [Member]

41,000

126,000

1,100,000

Finance Lease fixed purchase price

$ 28,200

$ 134,800

65 years

Area of Land | a

5.6

Joint Venture Partner [Member] | Platform 16 [Member]

55.00%

^[1]

55.00%

^[1]

55.00%

^[1]

$ 23,100

45.00%

[1]	This entity is a VIE (See Note 2).

Real Estate Finance Lease Liability, Maturity - Platform 16 (Details) - USD ($)
$ in Thousands

Sep. 30, 2019

Jul. 19, 2019

Jul. 16, 2019

Jan. 24, 2019

$ 150

907

5,958

10,208

9,708

^[1]

1,431,760

1,458,691

(1,237,662)

2100 Pennsylvania Avenue [Member]

$ 221,029

$ 0

3,863

8,576

8,669

1,358,518

1,379,626

(1,214,649)

$ 164,977

$ 165,000

2019

$ 17,918

2020

109,460

127,378

(4,815)

Finance leases under development

$ 122,563

[1]	Finance lease payments in 2024 include approximately $38.7 million related to a purchase option that the Company is reasonably certain it will exercise.

Real Estate Asset Acquisition - Waltham Woods Corporate Center (Details) - 880 & 890 Winter Street [Member] $ in Thousands	Aug. 27, 2019 USD ($)
Business Acquisition [Line Items]
Land	$ 31,376
Building and improvements	57,922
Tenant improvements	6,024
Net assets acquired	105,970
In-place lease intangibles [Member]
Business Acquisition [Line Items]
Lease intangibles	11,494
Above-market lease intangibles [Member]
Business Acquisition [Line Items]
Lease intangibles	246
Below-market lease intangibles [Member]
Business Acquisition [Line Items]
Lease intangibles	$ (1,092)

Real Estate Asset Acquisition - Lease Intangibles Amortization (Details) - 880 & 890 Winter Street [Member] $ in Thousands	Aug. 27, 2019 USD ($)
Acquired In-Place Lease Intangibles [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Period from August 27, 2019 through December 31, 2019	$ 1,801
2020	4,485
2021	2,391
2022	1,121
2023	179
2024	60
Acquired Above-Market Lease Intangibles [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Period from August 27, 2019 through December 31, 2019	28
2020	80
2021	80
2022	43
2023	15
2024	0
Acquired Below-Market Lease Intangibles [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Period from August 27, 2019 through December 31, 2019	(226)
2020	(599)
2021	(237)
2022	(30)
2023	0
2024	$ 0

Leases Narrative (Details)	3 Months Ended	9 Months Ended
Leases Narrative (Details)	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Jan. 01, 2019 USD ($)
Finance leases under development	3	3
Cumulative effect of a change in accounting principle		$ 4,379,000	$ (5,496,000)
Right of use assets - operating leases	$ 149,231,000	149,231,000		$ 151,800,000
Lease liabilities - operating leases	$ 199,755,000	199,755,000		$ 199,300,000
Lessee, Finance Lease, Description	four
Boston Properties Limited Partnership
Right of use assets - operating leases	$ 149,231,000	149,231,000
Lease liabilities - operating leases	199,755,000	199,755,000
Dividends In Excess Of Earnings [Member]
Cumulative effect of a change in accounting principle		3,864,000	(4,933,000)
Dividends In Excess Of Earnings [Member] \| Boston Properties Limited Partnership
Cumulative effect of a change in accounting principle		3,900,000
Noncontrolling Interests - Common units [Member]
Cumulative effect of a change in accounting principle		445,000	$ (563,000)
Noncontrolling Interests - Common units [Member] \| Boston Properties Limited Partnership
Cumulative effect of a change in accounting principle		400,000
Noncontrolling interest - property partnerships [Member]
Cumulative effect of a change in accounting principle	$ 0	70,000
Noncontrolling interest - property partnerships [Member] \| Boston Properties Limited Partnership
Cumulative effect of a change in accounting principle		$ 70,000

Leases Lessee, Lease Costs and Other Information (Details)
$ in Thousands

3 Months Ended

9 Months Ended

Sep. 30, 2019

USD ($)

Sep. 30, 2019

USD ($)

Leases [Abstract]

Operating lease costs

$ 3,637

$ 10,970

Finance Lease, Amortization of right of use asset

^[1]

Finance Lease, Interest on lease liabilities

$ 12

^[2]

$ 36

^[2]

Operating Lease, Weighted Average Remaining Lease Term

51 years

Finance Lease, Weighted Average Remaining Lease Term

72 years

Operating Lease, Weighted Average Discount Rate, Percent

5.70%

Finance Lease, Weighted Average Discount Rate, Percent

6.20%

[1]

The finance leases relate to either land, buildings or assets that remain in development. For land leases classified as finance leases because of a purchase option that the Company views as an economic incentive, the Company follows its existing policy and does not depreciate land because it is assumed to

[2]

Three of the finance leases relate to assets under development and as such, the entire interest amount was capitalized.

Leases Future Minimum Lease Payments for Ground Leases (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Leases [Abstract]
2019	$ 11,425
2020	18,425
2021	25,310
2022	8,894
2023	9,084
Thereafter	$ 567,232

Leases Future Minimum Lease Payments, Capital Leases (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Leases [Abstract]
2019	$ 1,441
2020	12,682
2021	2,123
2022	1,253
2023	944
Thereafter	73,241
Total expected minimum lease payments	91,684
Interest portion	(27,497)
Present value of expected net minimum lease payments	$ 64,187

Leases Lease Liability Maturity Schedule (Details) - USD ($)
$ in Thousands

Sep. 30, 2019

Jan. 01, 2019

Operating Leases

October 1, 2019 - December 31, 2019

$ 2,426

10,050

24,953

18,041

10,345

567,232

633,047

Less: interest portion

(433,292)

Present value of lease payments

199,755

$ 199,300

Finance Leases

October 1, 2019 - December 31, 2019

150

907

5,958

10,208

9,708

^[1]

1,431,760

1,458,691

(1,237,662)

Lessee, Finance Lease, Option to Extend, Reasonably Certain 2024

221,029

$ 38,700

[1]	Finance lease payments in 2024 include approximately $38.7 million related to a purchase option that the Company is reasonably certain it will exercise.

Leases Lessor, Lease Income Table (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019
Leases [Abstract]
Fixed contractual payments	$ 566,294	$ 1,678,100
Variable lease payments	125,931	373,565
Lease	$ 692,225	$ 2,051,665

Leases Lessor , Future Minimum Rents (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Leases [Abstract]
October 1, 2019 - December 31, 2019	$ 530,470
2019		$ 2,088,171
2020	2,196,428	2,106,963
2021	2,177,016	2,015,031
2022	2,050,537	1,838,699
2023	1,980,918	1,736,636
Thereafter	$ 15,447,131	$ 12,295,464

Investments in Unconsolidated Joint Ventures (Investments in Unconsolidated Joint Ventures) (Details)
$ in Thousands

9 Months Ended

Sep. 05, 2019

USD ($)

ft²

Jun. 27, 2019

ft²

Apr. 26, 2019

USD ($)

ft²

Sep. 30, 2019

USD ($)

ft²

Land_Parcels

Buildings

payments

Sep. 20, 2019

ft²

Dec. 31, 2018

USD ($)

Schedule of Equity Method Investments [Line Items]

Carrying value of the Company's investments in unconsolidated joint ventures

$ (356,338)

$ (503,726)

$ 933,255

956,309

Square 407 Limited Partnership [Member]

Schedule of Equity Method Investments [Line Items]

Market Square North

50.00%

BP/CRF Metropolitan Square LLC [Member]

^[1]

$ (5,114)

(6,424)

Schedule of Equity Method Investments [Line Items]

Metropolitan Square

Carrying value of the Company's investments in unconsolidated joint ventures

20.00%

^[1]

$ 5,726

2,644

901 New York Avenue LLC [Member]

Schedule of Equity Method Investments [Line Items]

901 New York Avenue

^[2]

25.00%

WP Project Developer LLC [Member]

^[1]

$ (12,385)

(13,640)

Schedule of Equity Method Investments [Line Items]

Wisconsin Place Land and Infrastructure

Carrying value of the Company's investments in unconsolidated joint ventures

^[3]

33.30%

^[1]

$ 37,179

38,214

Annapolis Junction NFM, LLC [Member]

Schedule of Equity Method Investments [Line Items]

Annapolis Junction

Carrying value of the Company's investments in unconsolidated joint ventures

^[4]

50.00%

^[1]

$ 25,314

25,268

Number of real estate properties | Buildings

Parcels of undeveloped land | Land_Parcels

540 Madison Venture LLC [Member]

Schedule of Equity Method Investments [Line Items]

1.10%

540 Madison Avenue

Carrying value of the Company's investments in unconsolidated joint ventures

60.00%

^[5]

^[1]

$ 3,075

66,391

500 North Capitol Venture LLC [Member]

284,000

Schedule of Equity Method Investments [Line Items]

500 North Capitol Street, NW

30.00%

501 K Street LLC [Member]

^[1]

$ (5,661)

(5,026)

Schedule of Equity Method Investments [Line Items]

1001 6th Street

Carrying value of the Company's investments in unconsolidated joint ventures

^[6]

50.00%

^[1]

$ 42,555

42,557

Potential additonal payments to joint venture partner | payments

Minimum square footage to make a potential additional payment to joint venture partner (in sqft) | ft²

520,000

Podium Developer LLC [Member]

Schedule of Equity Method Investments [Line Items]

The Hub on Causeway - Podium

Carrying value of the Company's investments in unconsolidated joint ventures

50.00%

^[1]

$ 41,434

69,302

Residential Tower Developer LLC [Member]

Schedule of Equity Method Investments [Line Items]

The Hub on Causeway - Residential

Carrying value of the Company's investments in unconsolidated joint ventures

50.00%

^[1]

$ 48,491

47,505

Hotel Tower Developer LLC [Member]

Schedule of Equity Method Investments [Line Items]

The Hub on Causeway - Hotel Air Rights

Carrying value of the Company's investments in unconsolidated joint ventures

50.00%

^[1]

$ 3,917

3,022

Office Tower Developer LLC [Member]

Schedule of Equity Method Investments [Line Items]

$ 400,000

1.50%

100 Causeway Street

Carrying value of the Company's investments in unconsolidated joint ventures

50.00%

^[1]

$ 74,083

23,804

1265 Main Office JV LLC [Member]

632,000

Schedule of Equity Method Investments [Line Items]

1265 Main Street

Carrying value of the Company's investments in unconsolidated joint ventures

50.00%

^[1]

$ 3,932

3,918

BNY Tower Holdings LLC [Member]

Schedule of Equity Method Investments [Line Items]

Dock 72

Carrying value of the Company's investments in unconsolidated joint ventures

50.00%

^[1]

$ 94,700

82,520

CA-Colorado Center Limited Partnership [Member]

Schedule of Equity Method Investments [Line Items]

Colorado Center

Carrying value of the Company's investments in unconsolidated joint ventures

50.00%

^[1]

$ 250,213

253,495

7750 Wisconsin Avenue LLC [Member]

Schedule of Equity Method Investments [Line Items]

$ 255,000

1.25%

7750 Wisconsin Avenue

Carrying value of the Company's investments in unconsolidated joint ventures

50.00%

^[1]

$ 55,662

69,724

BP-M 3HB Venture LLC [Member]

734,000

Schedule of Equity Method Investments [Line Items]

3 Hudson Boulevard

Carrying value of the Company's investments in unconsolidated joint ventures

25.00%

^[1]

$ 54,037

46,993

SMBP Venture LP [Member]

Schedule of Equity Method Investments [Line Items]

Santa Monica Business Park

Carrying value of the Company's investments in unconsolidated joint ventures

55.00%

^[1]

$ 163,809

180,952

Platform 16 Holdings LP [Member]

Schedule of Equity Method Investments [Line Items]

Platform 16

Carrying value of the Company's investments in unconsolidated joint ventures

55.00%

^[7]

55.00%

^[1]

$ 29,128

1,100,000

Schedule of Equity Method Investments [Line Items]

23,200

25,100

Schedule of Equity Method Investments [Line Items]

Carrying value of the Company's investments in unconsolidated joint ventures

(773,033)

^[8]

(582,006)

^[1],[9]

$ 910,095

$ 931,219

[1]	Investments with deficit balances aggregating approximately $23.2 million and $25.1 million at September 30, 2019 and December 31, 2018, respectively, have been reflected within Other Liabilities in the Company’s Consolidated Balance Sheets.
[2]	The Company’s economic ownership has increased based on the achievement of certain return thresholds.
[3]	The Company’s wholly-owned subsidiary that owns Wisconsin Place Office also owns a 33.3% interest in the joint venture entity that owns the land, parking garage and infrastructure of the project.
[4]	The joint venture owns three in-service buildings and two undeveloped land parcels.
[5]	The property was sold on June 27, 2019. As of September 30, 2019, the investment is comprised of undistributed cash. See note below for additional details.
[6]	Under the joint venture agreement for this land parcel, the partner will be entitled to up to two additional payments from the venture based on increases in total entitled square footage of the project above 520,000 square feet and achieving certain project returns at stabilization.
[7]	This entity is a VIE (See Note 2).
[8]	At September 30, 2019, this amount includes lease liabilities - finance leases and lease liabilities - operating leases totaling approximately $511.7 million and $17.3 million, respectively.
[9]	Investments with deficit balances aggregating approximately $23.2 million and $25.1 million at September 30, 2019 and December 31, 2018, respectively, have been reflected within Other Liabilities in the Company’s Consolidated Balance Sheet

Investments in Unconsolidated Joint Ventures (Balance Sheets of the Unconsolidated Joint Ventures) (Details) - USD ($)
$ in Thousands

Sep. 30, 2019

Jan. 01, 2019

Dec. 31, 2018

ASSETS

Real estate and development in process, net

$ 17,511,072

$ 16,752,119

Liabilities and Members'/Partners' Equity [Abstract]

Total liabilities and equity / capital

2,952,006

2,964,572

Other Liabilities

356,338

503,726

21,288,575

20,256,477

Carrying value of the Company's investments in unconsolidated joint ventures

933,255

956,309

237,394

149,231

$ 151,800

Lease liabilities - operating leases

221,029

199,755

$ 199,300

Real estate and development in process, net

ASSETS

3,782,279

^[1]

3,545,906

Other assets

498,040

543,512

Total assets

4,280,319

4,089,418

Liabilities and Members'/Partners' Equity [Abstract]

Members'/Partners' equity

2,107,805

2,017,609

Other Liabilities

773,033

^[2]

582,006

1,399,481

1,489,803

Total liabilities and equity / capital

4,280,319

4,089,418

Company's share of equity

569,704

622,498

Basis differentials

^[3]

340,391

308,721

Carrying value of the Company's investments in unconsolidated joint ventures

^[4],[5]

910,095

931,219

Liabilities and Members'/Partners' Equity [Abstract]

Other Liabilities

(23,200)

(25,100)

383,900

12,300

Lease liabilities - operating leases

511,700

17,300

Colorado Center [Member] | Unconsolidated Joint Ventures [Member]

Liabilities and Members'/Partners' Equity [Abstract]

Basis differentials

$ 312,300

$ 316,700

[1]	At September 30, 2019, this amount includes right of use assets - finance leases and right of use assets - operating leases totaling approximately $383.9 million and $12.3 million, respectively.
[2]	At September 30, 2019, this amount includes lease liabilities - finance leases and lease liabilities - operating leases totaling approximately $511.7 million and $17.3 million, respectively.
[3]	This amount represents the aggregate difference between the Company’s historical cost basis and the basis reflected at the joint venture level, which is typically amortized over the life of the related assets and liabilities. Basis differentials result from impairments of investments, acquisitions through joint ventures with no change in control and upon the transfer of assets that were previously owned by the Company into a joint venture. In addition, certain acquisition, transaction and other costs may not be reflected in the net assets at the joint venture level. At September 30, 2019 and December 31, 2018, there was an aggregate basis differential of approximately $312.3 million and $316.7 million, respectively, between the carrying value of the Company’s investment in the joint venture that owns Colorado Center and the joint venture’s basis in the assets and liabilities, which differential (excluding land) shall be amortized over the remaining lives of the related assets and liabilities.
[4]	Investments with deficit balances aggregating approximately $23.2 million and $25.1 million at September 30, 2019 and December 31, 2018, respectively, have been reflected within Other Liabilities in the Company’s Consolidated Balance Sheets.
[5]	Investments with deficit balances aggregating approximately $23.2 million and $25.1 million at September 30, 2019 and December 31, 2018, respectively, have been reflected within Other Liabilities in the Company’s Consolidated Balance Sheet

Investments in Unconsolidated Joint Ventures (Statements of Operations of the Joint Ventures) (Details) - USD ($)
$ in Thousands

3 Months Ended

9 Months Ended

Jun. 27, 2019

Sep. 30, 2019

Sep. 30, 2018

Sep. 30, 2019

Sep. 30, 2018

Schedule of Equity Method Investments [Line Items]

$ 743,553

$ 686,284

$ 2,203,061

$ 2,011,919

Expenses

165,862

157,996

507,867

480,210

474,322

447,920

1,432,266

1,334,779

(106,471)

(95,366)

(309,837)

(277,790)

(15)

7,863

766

122,552

141,370

150,445

475,990

527,322

(649)

(4,313)

47,528

(3,083)

Schedule of Equity Method Investments [Line Items]

^[1]

75,940

76,177

239,099

189,759

Expenses

Operating

28,839

29,522

89,472

75,239

23,477

44,993

76,941

74,245

52,316

74,515

166,413

149,484

(20,483)

(19,861)

(62,043)

(48,993)

(812)

^[2]

33,760

^[2]

Company's share of net income (loss)

2,329

(18,199)

44,403

(8,718)

392

(2,858)

24,352

1,073

Basis differential

^[2],[3]

(1,041)

(1,455)

23,176

(4,156)

Straight-line rent adjustments

(649)

(4,313)

47,528

(3,083)

5,300

4,800

18,700

9,800

540 Madison Venture LLC [Member]

Equity Method Investment, Realized Gain (Loss) on Disposal

$ 47,300

(500)

Colorado Center [Member] | Unconsolidated Joint Ventures [Member]

Straight-line rent adjustments

500

1,600

1,900

"Above" and "below" market rent adjustments, net

$ 400

$ 1,300

$ 1,200

[1]	Includes straight-line rent adjustments of approximately $5.3 million and $4.8 million for the three months ended September 30, 2019 and 2018, respectively, and $18.7 million and $9.8 million for the nine months ended September 30, 2019 and 2018, respectively.
[2]	Represents the total gain on sale of 540 Madison Avenue recognized by the joint venture, as described below. During 2008, the Company recognized an other-than-temporary impairment loss on its investment in the unconsolidated joint venture resulting in a basis differential between the carrying value of the Company’s investment in the joint venture and the joint venture’s basis in the assets and liabilities of the property. As a result of the historical basis difference, the Company recognized a gain on sale of real estate totaling approximately $47.3 million for the nine months ended September 30, 2019, which consists of its share of the gain on sale reported by the joint venture as well as an adjustment for the basis differential. The Company recognized a reduction to the gain on sale of real estate totaling approximately $0.5 million for the three months ended September 30, 2019. The gain on sale is included in Income (Loss) from Unconsolidated Joint Ventures in the Company’s Consolidated Statements of Operations.
[3]	Includes straight-line rent adjustments of approximately $0.5 million and $0.5 million for the three months ended September 30, 2019 and 2018, respectively, and $1.6 million and $1.9 million for the nine months ended September 30, 2019 and 2018, respectively. Also includes net above-/below-market rent adjustments of approximately $0.4 million and $0.4 million for the three months ended September 30, 2019 and 2018, respectively, and $1.3 million and $1.2 million for the nine months ended September 30, 2019 and 2018, respectively

Investments in Unconsolidated Joint Ventures Narrative (Details)
$ in Thousands

3 Months Ended

9 Months Ended

Sep. 20, 2019

USD ($)

ft²

Sep. 16, 2019

USD ($)

Sep. 05, 2019

USD ($)

ft²

Jun. 27, 2019

USD ($)

ft²

Apr. 26, 2019

USD ($)

ft²

Jan. 24, 2019

USD ($)

ft²

Sep. 30, 2019

USD ($)

Sep. 30, 2019

USD ($)

Sep. 30, 2018

USD ($)

Jun. 15, 2019

ft²

May 28, 2019

USD ($)

Dec. 31, 2018

USD ($)

Schedule of Equity Method Investments [Line Items]

$ 2,952,006

$ 2,964,572

Annapolis Junction Building Six [Member]

$ 65,499

$ 314,075

Schedule of Equity Method Investments [Line Items]

50.00%

$ 13,000

Extension Option (in years)

2.00%

Debt instrument, borrowing capacity

$ 14,300

7750 Wisconsin Avenue LLC [Member]

119,000

Schedule of Equity Method Investments [Line Items]

50.00%

$ 255,000

1.25%

Proceeds from Construction Loans Payable

$ 39,600

The Hub on Causeway - Podium and 100 Causeway [Member]

734,000

Schedule of Equity Method Investments [Line Items]

Maximum proceeds from a state infrastructure development program

50.00%

$ 30,000

Net proceeds from a state infrastructure development program

$ 28,800

Hub on Causeway - Podium [Member]

Schedule of Equity Method Investments [Line Items]

Repayments of Construction Loans Payable

$ 28,800

540 Madison Venture LLC [Member]

375,000

Schedule of Equity Method Investments [Line Items]

60.00%

^[1]

60.00%

^[1]

Contractual Sales Price

$ 310,300

Loans Assumed

$ 120,000

Proceeds from Sale of Equity Method Investments

1.10%

$ 178,700

Equity Method Investment, Realized Gain (Loss) on Disposal

$ 47,300

$ (500)

100 Causeway Street [Member]

284,000

Schedule of Equity Method Investments [Line Items]

50.00%

$ 400,000

1.50%

Proceeds from Construction Loans Payable

$ 47,700

632,000

Schedule of Equity Method Investments [Line Items]

55.00%

^[2]

55.00%

^[2]

1,100,000

$ 28,200

Company's Share [Member] | 540 Madison Venture LLC [Member]

65 years

Area of Land | a

5.6

Schedule of Equity Method Investments [Line Items]

Proceeds from Sale of Equity Method Investments

$ 107,100

Joint Venture Partner [Member] | Platform 16 [Member]

Schedule of Equity Method Investments [Line Items]

45.00%

Stabilization as defined in the agreement [Member] | 100 Causeway Street [Member]

$ 23,100

Schedule of Equity Method Investments [Line Items]

1.375%

[1]	The property was sold on June 27, 2019. As of September 30, 2019, the investment is comprised of undistributed cash. See note below for additional details.
[2]	This entity is a VIE (See Note 2).

Unsecured Senior Notes (Details) - USD ($)
$ in Thousands

9 Months Ended

Sep. 30, 2019

Sep. 18, 2019

Sep. 03, 2019

Jun. 21, 2019

Dec. 31, 2018

$ 8,387,913

$ 7,544,697

Boston Properties Limited Partnership | Senior Notes [Member]

8,387,913

$ 7,544,697

Deferred financing costs, net

8,450,000

Net unamortized discount

18,232

43,855

Boston Properties Limited Partnership | Senior Notes [Member] | 10 Year Unsecured Senior Notes 5.708% [Member]

$ 8,387,913

Boston Properties Limited Partnership | Senior Notes [Member] | 10 Year Unsecured Senior Notes 4.289% [Member]

5.625%

Debt Instrument, Interest Rate, Effective Percentage

4.125%

^[1]

4.289%

$ 850,000

Boston Properties Limited Partnership | Senior Notes [Member] | 11 Year Unsecured Senior Notes 3.954%[Member]

^[2]

May 15, 2021

Debt Instrument, Interest Rate, Effective Percentage

3.85%

^[1]

3.954%

$ 1,000,000

Boston Properties Limited Partnership | Senior Notes [Member] | 10.5 year Unsecured Senior Notes 3.279% [Member]

^[2]

Feb. 01, 2023

Debt Instrument, Interest Rate, Effective Percentage

3.125%

^[1]

3.279%

$ 500,000

Boston Properties Limited Partnership | Senior Notes [Member] | 10.5 Year Unsecured Senior Notes 3.916%[Member]

^[2]

Sep. 01, 2023

Debt Instrument, Interest Rate, Effective Percentage

3.80%

^[1]

3.916%

$ 700,000

Boston Properties Limited Partnership | Senior Notes [Member] | 7 Year Unsecured Senior Notes 3.350% [Member]

^[2]

Feb. 01, 2024

Debt Instrument, Interest Rate, Effective Percentage

3.20%

^[1]

3.35%

$ 850,000

Boston Properties Limited Partnership | Senior Notes [Member] | 10 Year Unsecured Senior Notes 3.766%[Member]

^[2]

Jan. 15, 2025

Debt Instrument, Interest Rate, Effective Percentage

3.65%

^[1]

3.766%

$ 1,000,000

Boston Properties Limited Partnership | Senior Notes [Member] | 10 Year Unsecured Senior Notes 3.495% [Member]

^[2]

Feb. 01, 2026

Debt Instrument, Interest Rate, Effective Percentage

2.75%

^[1]

3.495%

$ 1,000,000

Boston Properties Limited Partnership | Senior Notes [Member] | 10 Year Unsecured Senior Notes 4.628%[Member]

^[2]

Oct. 01, 2026

Debt Instrument, Interest Rate, Effective Percentage

4.50%

^[1]

4.628%

$ 1,000,000

Boston Properties Limited Partnership | Senior Notes [Member] | 10 Year Unsecured Senior Notes 3.505% [Member]

^[2]

Dec. 01, 2028

Debt Instrument, Interest Rate, Effective Percentage

3.40%

^[1]

3.505%

$ 850,000

Boston Properties Limited Partnership | Senior Notes [Member] | 10.5 Year Unsecured Senior Notes 2.984% [Member]

^[2]

Jun. 21, 2029

Debt Instrument, Interest Rate, Effective Percentage

2.90%

^[1]

2.984%

$ 700,000

^[2]

Mar. 15, 2030

[1]	Yield on issuance date including the effects of discounts on the notes, settlements of interest rate contracts and the amortization of financing costs.
[2]	No principal amounts are due prior to maturity.

Unsecured Senior Notes Narrative (Details) - USD ($)
$ in Thousands

3 Months Ended

9 Months Ended

Sep. 18, 2019

Sep. 03, 2019

Jun. 21, 2019

Sep. 30, 2019

Sep. 30, 2018

Sep. 30, 2019

Sep. 30, 2018

Repayments of Unsecured Debt

$ 699,237

$ 0

$ 28,010

$ 0

28,010

1,548,106

Repayments of Unsecured Debt

699,237

28,010

$ 0

28,010

Boston Properties Limited Partnership | Senior Notes [Member]

1,548,106

$ 0

Debt Instrument, Covenant Description

8,450,000

$ 8,450,000

Boston Properties Limited Partnership | Senior Notes [Member] | 10 Year Unsecured Senior Notes 3.505% [Member]

$ 850,000

Senior Notes Pricing

99.815%

Debt Instrument, Interest Rate, Effective Percentage

3.40%

^[1]

3.505%

Boston Properties Limited Partnership | Senior Notes [Member] | 10.5 Year Unsecured Senior Notes 2.984% [Member]

$ 841,400

$ 700,000

Senior Notes Pricing

99.954%

Debt Instrument, Interest Rate, Effective Percentage

2.90%

^[1]

2.984%

Boston Properties Limited Partnership | Senior Notes [Member] | 10 Year Unsecured Senior Notes 5.708% [Member]

$ 693,800

Repayments of Unsecured Debt

5.625%

$ 740,700

Debt Instrument, Increase, Accrued Interest

$ 13,500

Debt Instrument, Redemption Price, Percentage

103.90%

Debt Instrument, Face Amount

$ (28,000)

Redemption Premium

27,300

$ 700,000

[1]	Yield on issuance date including the effects of discounts on the notes, settlements of interest rate contracts and the amortization of financing costs.

Commitments And Contingencies (Details) $ in Millions	9 Months Ended	12 Months Ended
Commitments And Contingencies (Details) $ in Millions	Sep. 30, 2019 USD ($) ft²	Dec. 31, 2009 USD ($)	May 09, 2019 ft²	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Jan. 10, 2014 USD ($)
Commitments And Contingencies [Line Items]
Letter of credit and performance obligations	$ 15.2
Property insurance program per occurrence limits	1,000.0
Per occurrence limit for NBCR Coverage	1,000.0
Value of program trigger	$ 180.0
Coinsurance of program trigger	19.00%
Deductible in insurance as a percentage of the value of the affected property, San Francisco and Los Angeles	3.00%
Per occurrence limit of the earthquake insurance which covers San Francisco and Los Angeles regions	$ 240.0
Annual aggregate limit of the earthquake insurance which covers San Francisco and Los Angeles regions	240.0
Amount of earthquake insurance provided by IXP, LLC as direct insurer San Francisco and Los Angeles	20.0
767 Venture, LLC [Member]
Commitments And Contingencies [Line Items]
Maximum funding obligation	71.7
Property insurance program per occurrence limits	1,625.0
Lehman [Member]
Commitments And Contingencies [Line Items]
Bankruptcy claim, amount filed by general creditor		$ 45.3
Bankruptcy claim amount allowed by court to creditor									$ 45.2
Bankruptcy Claims, Amount of Claims Settled				$ 0.3	$ 0.4	$ 1.4	$ 8.1	$ 7.7
Bankruptcy remaining claim amount allowed by court to creditor	27.2
325 Main Street [Member]
Commitments And Contingencies [Line Items]
Net Rentable Area (in sf) \| ft²			115,000
601 Lexington Avenue [Member]
Commitments And Contingencies [Line Items]
Coverage For Acts Of Terrorism Under TRIA Covered in Excess of Amount Covered by IXP	250.0
Boston Properties Limited Partnership
Commitments And Contingencies [Line Items]
Operating partnership guarantee to cover liabilities of IXP	$ 20.0
Residential Real Estate [Member] \| 325 Main Street [Member]
Commitments And Contingencies [Line Items]
Net Rentable Area (in sf) \| ft²	200,000
Affordable Housing requirement			25.00%
Future Office Building [Member] \| 325 Main Street [Member]
Commitments And Contingencies [Line Items]
Net Rentable Area (in sf) \| ft²			420,000
Future Retail Building [Member] \| 325 Main Street [Member]
Commitments And Contingencies [Line Items]
Net Rentable Area (in sf) \| ft²			41,000
Home ownership units [Member] \| Residential Real Estate [Member] \| 325 Main Street [Member]
Commitments And Contingencies [Line Items]
Affordable Housing requirement			20.00%

Noncontrolling Interests (Narrative) (Details) - Boston Properties Limited Partnership	Sep. 30, 2019 shares
Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Operating Partnership (OP) Units (in shares)	16,821,620
Long-Term Incentive Plan (LTIP) Units (in shares)	1,189,117
OPP Units 2012 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Outperformance awards in LTIP Units (in shares)	118,067
2013 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2013 MYLTIP (in units)	68,659
2014 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2014 MYLTIP (in units)	23,100
2015 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2015 MYLTIPS (in units)	28,724
2016 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2016 MYLTIPs (in units)	98,706
2017 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2017 MYLTIP (in units)	394,921
2018 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2018 MYLTIP (in units)	336,195
2019 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2019 MYLTIPS (in units)	220,734

(Common Units) (Narrative) (Details) $ / shares in Units, $ in Thousands		9 Months Ended
	Feb. 09, 2019 USD ($) shares	Sep. 30, 2019 USD ($) shares yr $ / shares	Dec. 31, 2018 USD ($)
OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
OP Units for redemption (in shares)		41,577
Redemption of OP units issued on conversion of LTIP Units (in shares)		39,377
Restriction on redemption of OP Unit to Common Stock (in years) \| yr		1
Redemption of OP Unit equivalent to Common Stock (in shares)		1
Common units of operating partnership if converted value \| $		$ 2,300,000
Closing price of common stock (in dollars per share) \| $ / shares		$ 129.66
2016 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Final awards percentage of target	69.50%
Value of MYLTIP Awards \| $	$ 13,600
2016 MYLTIP Units Forfeited	364,980
Boston Properties Limited Partnership
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Common units of operating partnership if converted value \| $		$ 2,335,272	$ 2,000,591
Boston Properties Limited Partnership \| OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
MYLTIP distribution prior to measurement date		10.00%
Boston Properties Limited Partnership \| 2017 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2017 MYLTIP (in units)		394,921
Boston Properties Limited Partnership \| 2018 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2018 MYLTIP (in units)		336,195
Boston Properties Limited Partnership \| 2019 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2019 MYLTIPS (in units)		220,734

Noncontrolling Interests Common units distributions (Details) - Boston Properties Limited Partnership - $ / shares	Jul. 31, 2019	Apr. 30, 2019	Jan. 30, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 30, 2018	Sep. 17, 2019
Dividends Payable [Line Items]
Distributions Declared To OP And LTIP Units Per Unit								$ 0.95
Distributions Declared To MYLTIP Units Per Unit (in dollars per unit)								$ 0.095
Distributions made to OP and LTIP units per unit (in dollars per unit)	$ 0.95	$ 0.95	$ 0.95	$ 0.95	$ 0.80	$ 0.80	$ 0.80
Distribution paid to MYLTIP Units (in dollars per unit)	$ 0.095	$ 0.095	$ 0.095	$ 0.095	$ 0.080	$ 0.080	$ 0.080

Noncontrolling Interests (Property Partnerships) (Narrative) (Details) $ in Thousands			3 Months Ended	9 Months Ended
	Apr. 01, 2019 USD ($)	May 12, 2016 ft²	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Noncontrolling Interest [Line Items]
Noncontrolling Interest in Limited Partnerships			$ 1,720,123	$ 1,720,123		$ 1,711,445
Payments to Noncontrolling Interests				53,149	$ 56,796
Acquisition of noncontrolling interest in property partnerships			43	(186,963)
Salesforce Tower [Member] \| Consolidated Properties [Member]
Noncontrolling Interest [Line Items]
Portion of project costs covered by a construction loan		50.00%
Portion of costs funded (in percentage)		50.00%
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners		5.00%
Debt Instrument, Basis Spread on Variable Rate		3.00%
Stabilization definition for Salesforce Tower		The term stabilization date was defined in the agreement to generally mean the first date after completion upon which Salesforce Tower is (1) at least 90% leased and (2) 50% occupied by tenants that are paying rent.
Net Rentable Area (in sf) \| ft²		1,421,000
Salesforce Tower [Member] \| Parent Company [Member] \| Consolidated Properties [Member]
Noncontrolling Interest [Line Items]
Costs funded (in percentage)		2.50%
Preferred equity funded			$ 22,600	$ 22,600
Salesforce Tower [Member]
Noncontrolling Interest [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	5.00%
Payments to Noncontrolling Interests	$ 210,900
Repayment of Preferred Equity	24,100
Net Payments To Minority Shareholders	$ 186,800
Amount of property owned	100.00%
Acquisition of noncontrolling interest in property partnerships	$ 162,500

Stockholders' Equity / Partners' Capital Narrative (Details)		9 Months Ended
	Jun. 02, 2017 USD ($) yr	Sep. 30, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Mar. 27, 2018 $ / shares	Jun. 03, 2014 USD ($)
Class of Stock [Line Items]
Common stock, shares outstanding		154,572,073	154,458,478
General Partners' Capital Account, Units Outstanding		1,725,828
Limited Partners' Capital Account, Units Outstanding		152,846,245
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period		29,704
Shares of Common Stock in connection with the redemption of an equal number of OP Units (in shares)		41,577
Common Stock, Value, Issued \| $		$ 1,546,000	$ 1,545,000
ATM Program [Member]
Class of Stock [Line Items]
At the market stock offering program, aggregate value of common stock \| $	$ 600,000,000.0				$ 600,000,000.0
At Market Stock Offering Program Maximum Length Of Sale In Years \| yr	3
Common Stock, Value, Issued \| $		$ 0
Series B Cumulative Redeemable Preferred Stock [Member]
Class of Stock [Line Items]
Series B, Shares Outstanding (in shares)		80,000	80,000
Series B, Dividend Rate, Percentage		5.25%
Series B, Liquidation Preference Per Share (dollars per share) \| $ / shares		$ 2,500.00	$ 2,500	$ 2,500.00
Ratio of depository shares to shares of Series B Preferred Stock		0.01
Depository shares of Series B Cumulative Redeemable Preferred [Member]
Class of Stock [Line Items]
Series B, Shares Outstanding (in shares)		8,000,000
Series B, Liquidation Preference Per Share (dollars per share) \| $ / shares		$ 25.00		$ 25.00
Boston Properties Limited Partnership
Class of Stock [Line Items]
General Partners' Capital Account, Units Outstanding		1,725,828	1,722,336
Limited Partners' Capital Account, Units Outstanding		152,846,245	152,736,142
Boston Properties Limited Partnership \| Series B Cumulative Redeemable Preferred Stock [Member]
Class of Stock [Line Items]
Series B, Shares Outstanding (in shares)		80,000	80,000
Series B, Liquidation Preference Per Share (dollars per share) \| $ / shares		$ 2,500	$ 2,500

Stockholders' Equity / Partners' Capital Stockholders' Equity / Partners' Capital Dividends / Distributions (Details) - $ / shares	Aug. 15, 2019	Jul. 31, 2019	May 15, 2019	Apr. 30, 2019	Feb. 15, 2019	Jan. 30, 2019	Nov. 15, 2018	Oct. 31, 2018	Aug. 15, 2018	Jul. 31, 2018	May 15, 2018	Apr. 30, 2018	Feb. 15, 2018	Jan. 30, 2018	Sep. 17, 2019
Entity Information [Line Items]
Dividends Payable, Amount Per Share / Unit															$ 0.95
Dividends, Per Share / Unit		$ 0.95		$ 0.95		$ 0.95		$ 0.95		$ 0.80		$ 0.80		$ 0.80
Boston Properties Limited Partnership
Entity Information [Line Items]
Dividends Payable, Amount Per Share / Unit															0.95
Dividends, Per Share / Unit		$ 0.95		$ 0.95		$ 0.95		$ 0.95		$ 0.80		$ 0.80		$ 0.80
Series B Cumulative Redeemable Preferred Stock [Member]
Entity Information [Line Items]
Dividends Payable, Amount Per Share / Unit															$ 32.8125
Dividends, Per Share / Unit	$ 32.8125		$ 32.8125		$ 32.8125		$ 32.8125		$ 32.8125		$ 32.8125		$ 32.8125

Earnings Per Share / Common Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Basic Earnings:
Net income attributable to the Company's common shareholders / unitholders	$ 107,771	$ 119,118	$ 370,200	$ 423,835
Net income attributable to the Company's common shareholders / unitholders (in shares / units)	154,577,000	154,440,000	154,553,000	154,414,000
Net income (in dollars per share / unit)	$ 0.70	$ 0.77	$ 2.40	$ 2.74
Allocation of undistributed earnings to participating securities				$ (87)
Allocation of undistributed earnings to participating securities (in shares)				0
Allocation of undistributed earnings to participating securities (in dollars per shares / units)				$ 0
Net income attributable to the Company's common shareholders / unitholders				$ 423,748
Net income attributable to the Company's common shareholders / unitholders (in shares / units)				154,414,000
Net income attributable to the Company's common shareholders / unitholders (in dollars per share / unit)				$ 2.74
Effect of Dilutive Securities:
Stock Based Compensation, Income (Numerator)	$ 0	$ 0	$ 0	$ 0
Stock Based Compensation, Income (in shares / units)	243,000	238,000	294,000	238,000
Stock Based Compensation, Income (in dollars per share / unit)	$ 0	$ 0	$ (0.01)	$ 0
Diluted Earnings:
Net income attributable to the Company's common shareholders / unitholders (Numerator)	$ 107,771	$ 119,118	$ 370,200	$ 423,748
Net income attributable to to the Company's shareholders / unitholder (number of shares)	154,820,000	154,678,000	154,847,000	154,652,000
Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit)	$ 0.70	$ 0.77	$ 2.39	$ 2.74
Boston Properties Limited Partnership
Entity Information [Line Items]
Redeemable Common Units	17,638,000	17,488,000	17,630,000	17,490,000
Basic Earnings:
Net income attributable to the Company's common shareholders / unitholders	$ 122,117	$ 136,201	$ 421,214	$ 483,069
Net income attributable to the Company's common shareholders / unitholders (in shares / units)	172,215,000	171,928,000	172,183,000	171,904,000
Net income (in dollars per share / unit)	$ 0.71	$ 0.79	$ 2.45	$ 2.81
Allocation of undistributed earnings to participating securities				$ (97)
Allocation of undistributed earnings to participating securities (in shares)				0
Allocation of undistributed earnings to participating securities (in dollars per shares / units)				$ 0
Net income attributable to the Company's common shareholders / unitholders				$ 482,972
Net income attributable to the Company's common shareholders / unitholders (in shares / units)				171,904,000
Net income attributable to the Company's common shareholders / unitholders (in dollars per share / unit)				$ 2.81
Effect of Dilutive Securities:
Stock Based Compensation, Income (Numerator)	$ 0	$ 0	$ 0	$ 0
Stock Based Compensation, Income (in shares / units)	243,000	238,000	294,000	238,000
Stock Based Compensation, Income (in dollars per share / unit)	$ 0	$ 0	$ (0.01)	$ 0
Diluted Earnings:
Net income attributable to the Company's common shareholders / unitholders (Numerator)	$ 122,117	$ 136,201	$ 421,214	$ 482,972
Net income attributable to to the Company's shareholders / unitholder (number of shares)	172,458,000	172,166,000	172,477,000	172,142,000
Diluted Earnings: Net income, Per Share Amount (in dollars per share / unit)	$ 0.71	$ 0.79	$ 2.44	$ 2.81

Stock Option and Incentive Plan Stock Option and Incentive Plan (Narrative) (Details) - USD ($) $ in Millions	Feb. 09, 2019	Feb. 05, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights		Earned awards (if any) will vest 50% on February 4, 2022 and 50% on February 4, 2023, based on continued employment. Vesting will be accelerated in the event of a change in control, termination of employment by Boston Properties, Inc. without cause, or termination of employment by the award recipient for good reason, death, disability or retirement. If there is a change of control prior to February 4, 2022, earned awards will be calculated based on TSR performance up to the date of the change of control. The 2019 MYLTIP awards are in the form of LTIP Units issued on the grant date which (i) are subject to forfeiture to the extent awards are not earned and (ii) prior to the performance measurement date are only entitled to one-tenth (10%) of the regular quarterly distributions payable on common partnership units.
2019 MYLTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
TSR Measurement, Years		three year
Minimum earned awards		0
Maximum Earned Awards		220,734
Target Tier		110,367
Value of MYLTIP Awards		$ 13.5
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period		4 years
2016 MYLTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value of MYLTIP Awards	$ 13.6
Final awards percentage of target	69.50%
2016 MYLTIP Units Forfeited	364,980

Stock Option and Incentive Plan Restricted Stock (Narrative) (Details) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019 USD ($) $ / shares shares	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) $ / shares shares	Sep. 30, 2018 USD ($)	Dec. 31, 2018 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued \| shares	154,650,973		154,650,973		154,537,378
Common Stock, Value, Issued	$ 1,546		$ 1,546		$ 1,545
Stock based compensation expense	$ 7,500	$ 7,900	$ 32,400	$ 30,100
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued \| shares	26,503		26,503
Employee and director payment per share (in dollars per share) \| $ / shares			$ 0.01
Common Stock, Value, Issued	$ 3,500		$ 3,500
Employee's weighted average cost per share (in dollars per share) \| $ / shares	$ 131.27		$ 131.27
LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value of LTIP units issued			$ 22,100
Per unit fair value weighted-average (in dollars per share) \| $ / shares	$ 121.50		$ 121.50
Expected life assumed to calculate per unit fair value per LTIP unit (years)			5 years 8 months 12 days
Risk-free rate			2.68%
Expected price volatility			27.00%
LTIPs (including vested 2012 OPP Awards and vested MYLTIPS) And Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting annual installments			4
Unrecognized compensation expenses	$ 28,900		$ 28,900
Unvested MYLTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expenses	$ 15,100		$ 15,100
Weighted-average period (years)			2 years 6 months
Boston Properties Limited Partnership \| LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
LTIP units issued (in shares) \| shares	181,919		181,919
Boston Properties Limited Partnership \| 2019 MYLTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
MYLTIP units issued (in shares) \| shares	220,734		220,734
Boston Properties Limited Partnership \| LTIPs and 2019 MYLTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee and director payment per share (in dollars per share) \| $ / shares			$ 0.25

Segment Information (Schedule Of Reconciliation Of Net Operating Income To Net Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	$ 107,771	$ 119,118	$ 370,200	$ 423,835
Preferred Stock Dividends / Distributions	(2,625)	(2,625)	(7,875)	(7,875)
Noncontrolling interest-common units of the Operating Partnership	(12,504)	(13,852)	(43,133)	(49,128)
Noncontrolling interest in property partnerships	(18,470)	(14,850)	(54,782)	(46,484)
Interest expense	(106,471)	(95,366)	(309,837)	(277,790)
Loss from early extinguishment of debt	28,010	0	28,010	0
Company's share of net operating income from joint ventures	(456,475)	(411,698)	(1,358,491)	(1,219,835)
Depreciation and amortization expense	(165,862)	(157,996)	(507,867)	(480,210)
Transaction costs	(538)	(914)	(1,415)	(1,409)
General and administrative expense	(31,147)	(29,677)	(107,980)	(94,039)
Gains from investments in securities	(106)	(1,075)	(4,240)	(1,454)
Interest and other income	(7,178)	(2,822)	(14,546)	(7,049)
Income (loss) from unconsolidated joint ventures	649	4,313	(47,528)	3,083
Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	107,771	119,118	370,200	423,835
Preferred Stock Dividends / Distributions	2,625	2,625	7,875	7,875
Noncontrolling interest-common units of the Operating Partnership	12,504	13,852	43,133	49,128
Noncontrolling interest in property partnerships	18,470	14,850	54,782	46,484
Interest expense	106,471	95,366	309,837	277,790
Loss from early extinguishment of debt	(28,010)	0	(28,010)	0
Impairment loss	0	0	24,038	0
Depreciation and amortization expense	165,862	157,996	507,867	480,210
Transaction costs	538	914	1,415	1,409
Payroll and related costs from management service contracts	2,429	2,516	8,227	7,371
General and administrative expense	31,147	29,677	107,980	94,039
Gains from investments in securities	106	1,075	4,240	1,454
Interest and other income	7,178	2,822	14,546	7,049
Gains (losses) on sales of real estate	(15)	7,863	766	122,552
Income (loss) from unconsolidated joint ventures	(649)	(4,313)	47,528	(3,083)
Direct reimbursement of payroll and related costs from management service contracts	2,429	2,516	8,227	7,371
Company's Share of Net Operating Income	433,291	391,141	1,292,724	1,142,607
Boston Properties Limited Partnership
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	122,117	136,201	421,214	483,069
Preferred Stock Dividends / Distributions	(2,625)	(2,625)	(7,875)	(7,875)
Noncontrolling interest in property partnerships	(18,470)	(14,850)	(54,782)	(46,484)
Interest expense	(106,471)	(95,366)	(309,837)	(277,790)
Loss from early extinguishment of debt	28,010	0	28,010	0
Depreciation and amortization expense	(164,020)	(156,056)	(501,901)	(474,383)
Transaction costs	(538)	(914)	(1,415)	(1,409)
General and administrative expense	(31,147)	(29,677)	(107,980)	(94,039)
Gains from investments in securities	(106)	(1,075)	(4,240)	(1,454)
Interest and other income	(7,178)	(2,822)	(14,546)	(7,049)
Income (loss) from unconsolidated joint ventures	649	4,313	(47,528)	3,083
Boston Properties Limited Partnership \| Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	122,117	136,201	421,214	483,069
Preferred Stock Dividends / Distributions	2,625	2,625	7,875	7,875
Noncontrolling interest in property partnerships	18,470	14,850	54,782	46,484
Interest expense	106,471	95,366	309,837	277,790
Loss from early extinguishment of debt	28,010	0	28,010	0
Impairment loss	0	0	22,272	0
Depreciation and amortization expense	164,020	156,056	501,901	474,383
Transaction costs	538	914	1,415	1,409
Payroll and related costs from management service contracts	2,429	2,516	8,227	7,371
General and administrative expense	31,147	29,677	107,980	94,039
Gains from investments in securities	106	1,075	4,240	1,454
Interest and other income	7,178	2,822	14,546	7,049
Gains (losses) on sales of real estate	(15)	9,154	915	126,831
Income (loss) from unconsolidated joint ventures	(649)	(4,313)	47,528	(3,083)
Direct reimbursement of payroll and related costs from management service contracts	2,429	2,516	8,227	7,371
Company's Share of Net Operating Income	433,291	391,141	1,292,724	1,142,607
Development and Management Services [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Payroll and related costs from management service contracts	(2,429)	(2,516)	(8,227)	(7,371)
Direct reimbursement of payroll and related costs from management service contracts	(10,303)	(15,253)	(29,566)	(32,963)
Development and Management Services [Member] \| Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Direct reimbursement of payroll and related costs from management service contracts	10,303	15,253	29,566	32,963
Development and Management Services [Member] \| Boston Properties Limited Partnership
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Payroll and related costs from management service contracts	(2,429)	(2,516)	(8,227)	(7,371)
Direct reimbursement of payroll and related costs from management service contracts	(10,303)	(15,253)	(29,566)	(32,963)
Development and Management Services [Member] \| Boston Properties Limited Partnership \| Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Direct reimbursement of payroll and related costs from management service contracts	10,303	15,253	29,566	32,963
Noncontrolling interest - property partnerships [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Company's share of net operating income from joint ventures	46,249	43,068	138,896	132,026
Noncontrolling interest - property partnerships [Member] \| Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Company's share of net operating income from joint ventures	46,249	43,068	138,896	132,026
Unconsolidated Joint Ventures [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest expense	(20,483)	(19,861)	(62,043)	(48,993)
Company's share of net operating income from joint ventures	(23,065)	(22,511)	(73,129)	(54,798)
Depreciation and amortization expense	(23,477)	(44,993)	(76,941)	(74,245)
Income (loss) from unconsolidated joint ventures	649	4,313	(47,528)	3,083
Unconsolidated Joint Ventures [Member] \| Business Intersegment, Eliminations [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Company's share of net operating income from joint ventures	$ (23,065)	$ (22,511)	$ (73,129)	$ (54,798)

Segment Information (Schedule Of Segment Reporting By Geographic Area And Property Type) (Details) - USD ($)
$ in Thousands

3 Months Ended

9 Months Ended

Sep. 30, 2019

Sep. 30, 2018

Sep. 30, 2019

Sep. 30, 2018

^[1]

$ 707,811

$ 648,531

$ 2,101,762

$ 1,918,934

^[1]

9,996

6,320

26,710

15,278

^[1]

$ 730,821

$ 668,515

$ 2,165,268

$ 1,971,585

100.00%

$ 265,603

$ 247,989

$ 781,091

$ 726,108

$ 274,346

$ 256,817

$ 806,777

$ 751,750

100.00%

$ 456,475

$ 411,698

$ 1,358,491

$ 1,219,835

Company's Share of Net Operating Income: % of Grand Totals

100.00%

100.00%

Boston [Member]

^[1]

$ 224,345

$ 210,277

$ 659,717

$ 623,084

^[1]

3,809

1,905

9,732

4,252

^[1]

$ 241,168

$ 225,846

$ 706,245

$ 664,709

33.00%

33.78%

32.62%

33.71%

$ 91,265

$ 88,076

$ 267,853

$ 263,581

33.27%

34.30%

33.20%

35.06%

$ 149,903

$ 137,770

$ 438,392

$ 401,128

Company's Share of Net Operating Income: % of Grand Totals

32.84%

33.46%

32.27%

32.88%

32.60%

33.29%

31.87%

33.11%

Los Angeles [Member]

^[1]

$ 0

^[1]

^[1]

$ 0

0.00%

$ 0

0.00%

$ 0

Company's Share of Net Operating Income: % of Grand Totals

0.00%

3.39%

3.55%

2.38%

New York [Member]

^[1]

$ 251,806

$ 237,944

$ 761,993

$ 714,348

^[1]

^[1]

$ 251,806

$ 237,944

$ 761,993

$ 714,348

34.45%

35.60%

35.19%

36.23%

$ 98,698

$ 96,795

$ 292,478

$ 282,395

35.97%

37.68%

36.26%

37.57%

$ 153,108

$ 141,149

$ 469,515

$ 431,953

Company's Share of Net Operating Income: % of Grand Totals

33.54%

34.29%

34.56%

35.41%

27.05%

27.64%

28.18%

28.85%

San Francisco [Member]

^[1]

$ 136,290

$ 102,035

$ 391,851

$ 285,410

^[1]

^[1]

$ 136,290

$ 102,035

$ 391,851

$ 285,410

18.65%

15.26%

18.10%

14.48%

$ 45,900

$ 34,016

$ 130,733

$ 92,858

16.73%

13.25%

16.20%

12.35%

$ 90,390

$ 68,019

$ 261,118

$ 192,552

Company's Share of Net Operating Income: % of Grand Totals

19.80%

16.52%

19.22%

15.79%

20.86%

17.39%

20.16%

16.88%

Washington, DC [Member]

^[1]

$ 95,370

$ 98,275

$ 288,201

$ 296,092

^[1]

6,187

4,415

16,978

11,026

^[1]

$ 101,557

$ 102,690

$ 305,179

$ 307,118

13.90%

15.36%

14.09%

15.58%

$ 38,483

$ 37,930

$ 115,713

$ 112,916

14.03%

14.77%

14.34%

15.02%

$ 63,074

$ 64,760

$ 189,466

$ 194,202

Company's Share of Net Operating Income: % of Grand Totals

13.82%

15.73%

13.95%

15.92%

16.10%

18.29%

16.24%

18.78%

Office

$ 2,429

$ 2,516

$ 8,227

$ 7,371

261,592

244,265

769,184

717,199

Office | Boston [Member]

Office | Los Angeles [Member]

81,278

78,089

238,438

235,560

Office | New York [Member]

Office | San Francisco [Member]

98,698

96,795

292,478

282,395

Office | Washington, DC [Member]

45,900

34,016

130,733

92,858

Residential Properties [Member]

35,716

35,365

107,535

106,386

Residential Properties [Member] | Boston [Member]

4,011

3,724

11,907

8,909

Residential Properties [Member] | Los Angeles [Member]

1,244

1,159

3,729

2,379

Residential Properties [Member] | New York [Member]

Residential Properties [Member] | San Francisco [Member]

Residential Properties [Member] | Washington, DC [Member]

2,767

2,565

8,178

6,530

Hotel [Member]

^[1]

13,014

13,664

36,796

37,373

Hotel [Member] | Boston [Member]

8,743

8,828

25,686

25,642

^[1]

13,014

13,664

36,796

37,373

Hotel [Member] | Los Angeles [Member]

8,743

8,828

25,686

25,642

^[1]

Hotel [Member] | New York [Member]

^[1]

Hotel [Member] | San Francisco [Member]

^[1]

Hotel [Member] | Washington, DC [Member]

^[1]

Noncontrolling interest - property partnerships [Member]

Noncontrolling interest - property partnerships [Member] | Boston [Member]

(46,249)

(43,068)

(138,896)

(132,026)

Noncontrolling interest - property partnerships [Member] | Los Angeles [Member]

(10,379)

(8,332)

(29,783)

(24,879)

Noncontrolling interest - property partnerships [Member] | New York [Member]

Noncontrolling interest - property partnerships [Member] | San Francisco [Member]

(35,870)

(34,723)

(108,665)

(107,420)

Noncontrolling interest - property partnerships [Member] | Washington, DC [Member]

(13)

(448)

273

Unconsolidated Joint Ventures [Member] | Boston [Member]

23,065

22,511

73,129

54,798

Unconsolidated Joint Ventures [Member] | Los Angeles [Member]

1,686

781

3,276

2,096

Unconsolidated Joint Ventures [Member] | New York [Member]

14,702

13,246

45,864

27,222

Unconsolidated Joint Ventures [Member] | San Francisco [Member]

(27)

1,698

3,455

5,065

Unconsolidated Joint Ventures [Member] | Washington, DC [Member]

6,704

6,786

20,534

20,415

Company's Share [Member]

Company's Share [Member] | Boston [Member]

433,291

391,141

1,292,724

1,142,607

Company's Share [Member] | Los Angeles [Member]

141,210

130,219

411,885

378,345

Company's Share [Member] | New York [Member]

14,702

13,246

45,864

27,222

Company's Share [Member] | San Francisco [Member]

117,211

108,124

364,305

329,598

Company's Share [Member] | Washington, DC [Member]

90,390

68,006

260,670

192,825