Boston Properties (BXP) 10-K 28 Feb 17 2016 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2016	Feb. 22, 2017	Jun. 30, 2016
Document Information [Line Items]
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Entity Registrant Name	BOSTON PROPERTIES INC
Amendment Flag	false
Entity Central Index Key	1,037,540
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		153,836,251
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 20,130,147,347
Boston Properties Limited Partnership
Document Information [Line Items]
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Entity Registrant Name	BOSTON PROPERTIES LTD PARTNERSHIP
Amendment Flag	false
Entity Central Index Key	1,043,121
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding	0
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
ASSETS
Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $6,760,078 at December 31, 2016)	$ 20,147,263	$ 19,481,535
Less: accumulated depreciation (amounts related to VIEs of ($758,640) at December 31, 2016)	(4,222,235)	(3,925,894)
Total real estate	15,925,028	15,555,641
Cash and cash equivalents (amounts related to VIEs of $253,999 at December 31, 2016)	356,914	723,718
Cash held in escrows (amounts related to VIEs of $4,955 at December 31, 2016)	63,174	73,790
Investments in securities	23,814	20,380
Tenant and other receivables (amounts related to VIEs of $23,525 at December 31, 2016)	92,548	97,865
Accrued rental income (amounts related to VIEs of $224,185 at December 31, 2016)	799,138	754,883
Deferred charges, net (amounts related to VIEs of $290,436 at December 31, 2016)	686,163	704,867
Prepaid expenses and other assets (amounts related to VIEs of $42,718 at December 31, 2016)	129,666	185,118
Investments in unconsolidated joint ventures	775,198	235,224
Total assets	18,851,643	18,351,486
Liabilities:
Mortgage notes payable, net (amounts related to VIEs of $2,018,483 at December 31, 2016)	2,063,087	3,435,242
Unsecured senior notes, net	7,245,953	5,264,819
Unsecured line of credit	0	0
Mezzanine notes payable (amounts related to VIEs of $307,093 at December 31, 2016)	307,093	308,482
Outside members’ notes payable (amounts related to VIEs of $180,000 at December 31, 2016)	180,000	180,000
Accounts payable and accrued expenses (amounts related to VIEs of $110,457 at December 31, 2016)	298,524	274,709
Dividends and distributions payable	130,308	327,320
Accrued interest payable (amounts related to VIEs of $162,226 at December 31, 2016)	243,933	190,386
Other liabilities (amounts related to VIEs of $175,146 at December 31, 2016)	450,821	483,601
Total liabilities	10,919,719	10,464,559
Commitments and contingencies	0	0
Noncontrolling interest:
Redeemable interest in property partnership		0
Equity / Capital:
Excess stock, $0.01 par value, 150,000,000 shares authorized, none issued or outstanding	0	0
Preferred stock, $0.01 par value, 50,000,000 shares authorized;
5.25% Series B cumulative redeemable preferred stock / units, liquidation preference $2,500 per share / unit, 80,000 shares / units issued and outstanding at December 31, 2016 and December 31, 2015, respectively	200,000	200,000
Common stock, $0.01 par value, 250,000,000 shares authorized, 153,869,075 and 153,658,866 issued and 153,790,175 and 153,579,966 outstanding at December 31, 2016 and December 31, 2015, respectively	1,538	1,536
Additional paid-in capital	6,333,424	6,305,687
Dividends in excess of earnings	(693,694)	(780,952)
Treasury common stock at cost, 78,900 shares at December 31, 2016 and December 31, 2015	(2,722)	(2,722)
Accumulated other comprehensive loss	(52,251)	(14,114)
Total stockholders' equity attributable to Boston Properties, Inc.	5,786,295	5,709,435
Noncontrolling interests:
Common units of the Operating Partnership	614,982	603,092
Property partnerships	1,530,647	1,574,400
Total equity / capital	7,931,924	7,886,927
Total liabilities and equity / capital	18,851,643	18,351,486
Boston Properties Limited Partnership
ASSETS
Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $6,760,078 at December 31, 2016)	19,733,872	19,061,141
Less: accumulated depreciation (amounts related to VIEs of ($758,640) at December 31, 2016)	(4,136,364)	(3,846,816)
Total real estate	15,597,508	15,214,325
Cash and cash equivalents (amounts related to VIEs of $253,999 at December 31, 2016)	356,914	723,718
Cash held in escrows (amounts related to VIEs of $4,955 at December 31, 2016)	63,174	73,790
Investments in securities	23,814	20,380
Tenant and other receivables (amounts related to VIEs of $23,525 at December 31, 2016)	92,548	97,865
Accrued rental income (amounts related to VIEs of $224,185 at December 31, 2016)	799,138	754,883
Deferred charges, net (amounts related to VIEs of $290,436 at December 31, 2016)	686,163	704,867
Prepaid expenses and other assets (amounts related to VIEs of $42,718 at December 31, 2016)	129,666	185,118
Investments in unconsolidated joint ventures	775,198	235,224
Total assets	18,524,123	18,010,170
Liabilities:
Mortgage notes payable, net (amounts related to VIEs of $2,018,483 at December 31, 2016)	2,063,087	3,435,242
Unsecured senior notes, net	7,245,953	5,264,819
Unsecured line of credit	0	0
Mezzanine notes payable (amounts related to VIEs of $307,093 at December 31, 2016)	307,093	308,482
Outside members’ notes payable (amounts related to VIEs of $180,000 at December 31, 2016)	180,000	180,000
Accounts payable and accrued expenses (amounts related to VIEs of $110,457 at December 31, 2016)	298,524	274,709
Dividends and distributions payable	130,308	327,320
Accrued interest payable (amounts related to VIEs of $162,226 at December 31, 2016)	243,933	190,386
Other liabilities (amounts related to VIEs of $175,146 at December 31, 2016)	450,821	483,601
Total liabilities	10,919,719	10,464,559
Commitments and contingencies	0	0
Noncontrolling interest:
Redeemable partnership units—17,079,511 and 16,097,473 common units and 904,588 and 1,831,714 long term incentive units outstanding at redemption value at December 31, 2016 and December 31, 2015, respectively	2,262,040	2,286,689
Preferred stock, $0.01 par value, 50,000,000 shares authorized;
5.25% Series B cumulative redeemable preferred stock / units, liquidation preference $2,500 per share / unit, 80,000 shares / units issued and outstanding at December 31, 2016 and December 31, 2015, respectively	193,623	193,623
Boston Properties Limited Partnership partners’ capital—1,717,743 and 1,715,092 general partner units and 152,072,432 and 151,864,874 limited partner units outstanding at December 31, 2016 and December 31, 2015, respectively	3,618,094	3,490,899
Accumulated other comprehensive loss	(60,853)	(18,337)
Noncontrolling interests:
Property partnerships	1,530,647	1,574,400
Total equity / capital	5,342,364	5,258,922
Total liabilities and equity / capital	$ 18,524,123	$ 18,010,170

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
General Partners' Capital Account, Units Outstanding (in units)	1,717,743
Limited Partners' Capital Account, Units Outstanding (in units)	152,072,432
Excess stock, par value	$ 0.01	$ 0.01
Excess stock, shares authorized	150,000,000	150,000,000
Excess stock, shares issued	0	0
Excess stock, shares outstanding	0	0
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	153,869,075	153,658,866
Common stock, shares outstanding	153,790,175	153,579,966
Treasury common stock at cost, shares	78,900	78,900
Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $6,760,078 at December 31, 2016)	$ 20,147,263	$ 19,481,535
Less: accumulated depreciation (amounts related to VIEs of ($758,640) at December 31, 2016)	(4,222,235)	(3,925,894)
Cash and cash equivalents (amounts related to VIEs of $253,999 at December 31, 2016)	356,914	723,718
Cash held in escrows (amounts related to VIEs of $4,955 at December 31, 2016)	63,174	73,790
Tenant and other receivables (amounts related to VIEs of $23,525 at December 31, 2016)	92,548	97,865
Accrued rental income (amounts related to VIEs of $224,185 at December 31, 2016)	799,138	754,883
Deferred charges, net (amounts related to VIEs of $290,436 at December 31, 2016)	686,163	704,867
Prepaid expenses and other assets (amounts related to VIEs of $42,718 at December 31, 2016)	129,666	185,118
Mortgage notes payable, net (amounts related to VIEs of $2,018,483 at December 31, 2016)	2,063,087	3,435,242
Mezzanine notes payable (amounts related to VIEs of $307,093 at December 31, 2016)	307,093	308,482
Accounts Payable and Accrued Liabilities	298,524	274,709
Accrued interest payable (amounts related to VIEs of $162,226 at December 31, 2016)	243,933	190,386
Other liabilities (amounts related to VIEs of $175,146 at December 31, 2016)	$ 450,821	$ 483,601
Series B Cumulative Redeemable Preferred Stock / Unit [Member]
Preferred stock, par value	$ 0.01	$ 0
Preferred stock, shares authorized	92,000	92,000
Series B Dividend Rate Percentage	5.25%	5.25%
Preferred stock / units, shares / units issued (in shares / units)	80,000	80,000
Series B Liquidation Preference Per Share/ Unit	$ 2,500	$ 2,500
Preferred stock / units, shares / units outstanding (in shares / units)	80,000	80,000
Boston Properties Limited Partnership
Redeemable Partnership Units Series Four Preferred Units Shares Outstanding ( in units)	0	0
Redeemable Partnership Units Common Units Shares Outstanding (in units)	17,079,511	16,097,473
Redeemable Partnership Units Common Units Long Term Incentive Units At Redemption Value Units Outstanding (in units)	904,588	1,831,714
General Partners' Capital Account, Units Outstanding (in units)	1,717,743	1,715,092
Limited Partners' Capital Account, Units Outstanding (in units)	152,072,432	151,864,874
Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $6,760,078 at December 31, 2016)	$ 19,733,872	$ 19,061,141
Less: accumulated depreciation (amounts related to VIEs of ($758,640) at December 31, 2016)	(4,136,364)	(3,846,816)
Cash and cash equivalents (amounts related to VIEs of $253,999 at December 31, 2016)	356,914	723,718
Cash held in escrows (amounts related to VIEs of $4,955 at December 31, 2016)	63,174	73,790
Tenant and other receivables (amounts related to VIEs of $23,525 at December 31, 2016)	92,548	97,865
Accrued rental income (amounts related to VIEs of $224,185 at December 31, 2016)	799,138	754,883
Deferred charges, net (amounts related to VIEs of $290,436 at December 31, 2016)	686,163	704,867
Prepaid expenses and other assets (amounts related to VIEs of $42,718 at December 31, 2016)	129,666	185,118
Mortgage notes payable, net (amounts related to VIEs of $2,018,483 at December 31, 2016)	2,063,087	3,435,242
Mezzanine notes payable (amounts related to VIEs of $307,093 at December 31, 2016)	307,093	308,482
Accounts Payable and Accrued Liabilities	298,524	274,709
Accrued interest payable (amounts related to VIEs of $162,226 at December 31, 2016)	243,933	190,386
Other liabilities (amounts related to VIEs of $175,146 at December 31, 2016)	$ 450,821	$ 483,601
Boston Properties Limited Partnership | Series B Cumulative Redeemable Preferred Stock / Unit [Member]
Series B Dividend Rate Percentage	5.25%	5.25%
Preferred stock / units, shares / units issued (in shares / units)	80,000	80,000
Series B Liquidation Preference Per Share/ Unit	$ 2,500	$ 2,500
Preferred stock / units, shares / units outstanding (in shares / units)	80,000	80,000
Variable Interest Entity, Primary Beneficiary [Member]
Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $6,760,078 at December 31, 2016)	$ 6,760,078
Less: accumulated depreciation (amounts related to VIEs of ($758,640) at December 31, 2016)	(758,640)
Cash and cash equivalents (amounts related to VIEs of $253,999 at December 31, 2016)	253,999
Cash held in escrows (amounts related to VIEs of $4,955 at December 31, 2016)	4,955
Tenant and other receivables (amounts related to VIEs of $23,525 at December 31, 2016)	23,525
Accrued rental income (amounts related to VIEs of $224,185 at December 31, 2016)	224,185
Deferred charges, net (amounts related to VIEs of $290,436 at December 31, 2016)	290,436
Prepaid expenses and other assets (amounts related to VIEs of $42,718 at December 31, 2016)	42,718
Mortgage notes payable, net (amounts related to VIEs of $2,018,483 at December 31, 2016)	2,018,483
Mezzanine notes payable (amounts related to VIEs of $307,093 at December 31, 2016)	307,093
Outside member's notes payable	180,000
Accounts Payable and Accrued Liabilities	110,457
Accrued interest payable (amounts related to VIEs of $162,226 at December 31, 2016)	162,226
Other liabilities (amounts related to VIEs of $175,146 at December 31, 2016)	175,146
Variable Interest Entity, Primary Beneficiary [Member] | Boston Properties Limited Partnership
Real estate, at cost (amounts related to variable interest entities (“VIEs”) of $6,760,078 at December 31, 2016)	6,760,078
Less: accumulated depreciation (amounts related to VIEs of ($758,640) at December 31, 2016)	758,640
Cash and cash equivalents (amounts related to VIEs of $253,999 at December 31, 2016)	253,999
Cash held in escrows (amounts related to VIEs of $4,955 at December 31, 2016)	4,955
Tenant and other receivables (amounts related to VIEs of $23,525 at December 31, 2016)	23,525
Accrued rental income (amounts related to VIEs of $224,185 at December 31, 2016)	224,185
Deferred charges, net (amounts related to VIEs of $290,436 at December 31, 2016)	290,436
Prepaid expenses and other assets (amounts related to VIEs of $42,718 at December 31, 2016)	42,718
Mortgage notes payable, net (amounts related to VIEs of $2,018,483 at December 31, 2016)	2,018,483
Mezzanine notes payable (amounts related to VIEs of $307,093 at December 31, 2016)	307,093
Outside member's notes payable	180,000
Accounts Payable and Accrued Liabilities	110,457
Accrued interest payable (amounts related to VIEs of $162,226 at December 31, 2016)	162,226
Other liabilities (amounts related to VIEs of $175,146 at December 31, 2016)	$ 175,146

Consolidated Statements Of Oper

Consolidated Statements Of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue
Base rent	$ 2,017,767	$ 1,964,732	$ 1,886,339
Recoveries from tenants	358,975	355,508	339,365
Parking and other	100,910	101,981	102,593
Total rental revenue	2,477,652	2,422,221	2,328,297
Hotel revenue	44,884	46,046	43,385
Development and management services	28,284	22,554	25,316
Total revenue	2,550,820	2,490,821	2,396,998
Expenses
Rental	889,768	872,252	835,290
Hotel	31,466	32,084	29,236
General and administrative	105,229	96,319	98,937
Transaction costs	2,387	1,259	3,140
Impairment loss	1,783	0	0
Depreciation and amortization	694,403	639,542	628,573
Total expenses	1,725,036	1,641,456	1,595,176
Operating income	825,784	849,365	801,822
Other income (expense)
Income from unconsolidated joint ventures	8,074	22,770	12,769
Gain on sale of investment in unconsolidated joint venture	59,370	0	0
Interest and other income	7,230	6,777	8,765
Gains (losses) from investments in securities	2,273	(653)	1,038
Interest expense	(412,849)	(432,196)	(455,743)
Losses from early extinguishments of debt	(371)	(22,040)	(10,633)
Losses from interest rate contracts	(140)	0	0
Income before gains on sales of real estate	489,371	424,023	358,018
Gains on sales of real estate	80,606	375,895	168,039
Net income	569,977	799,918	526,057
Net income attributable to noncontrolling interests
Noncontrolling interests in property partnerships	2,068	(149,855)	(30,561)
Noncontrolling interest - redeemable preferred units	0	(6)	(1,023)
Noncontrolling interest - common units of the Operating Partnership	(59,260)	(66,951)	(50,862)
Net income attributable to the Company	512,785	583,106	443,611
Preferred dividends / distributions	(10,500)	(10,500)	(10,500)
Net income attributable to the Company's common shareholders / unitholders	$ 502,285	$ 572,606	$ 433,111
Basic earnings per common share / unit attributable to the Company
Net income (in dollars per share / unit)	$ 3.27	$ 3.73	$ 2.83
Weighted average number of common shares / units outstanding (in shares / units)	153,715	153,471	153,089
Diluted earnings per common share / unit attributable to the Company
Diluted Earnings: Net income, Per Share / Unit Amount (in dollars per share / unit)	$ 3.26	$ 3.72	$ 2.83
Weighted average number of common and common equivalent shares / units outstanding (in shares / units)	153,977	153,844	153,308
Dividends/Distributions per common share/unit	$ 2.70	$ 3.85	$ 7.10
Boston Properties Limited Partnership
Revenue
Base rent	$ 2,017,767	$ 1,964,732	$ 1,886,339
Recoveries from tenants	358,975	355,508	339,365
Parking and other	100,910	101,981	102,593
Total rental revenue	2,477,652	2,422,221	2,328,297
Hotel revenue	44,884	46,046	43,385
Development and management services	28,284	22,554	25,316
Total revenue	2,550,820	2,490,821	2,396,998
Expenses
Rental	889,768	872,252	835,290
Hotel	31,466	32,084	29,236
General and administrative	105,229	96,319	98,937
Transaction costs	2,387	1,259	3,140
Impairment loss	1,783	0	0
Depreciation and amortization	682,776	631,549	620,064
Total expenses	1,713,409	1,633,463	1,586,667
Operating income	837,411	857,358	810,331
Other income (expense)
Income from unconsolidated joint ventures	8,074	22,770	12,769
Gain on sale of investment in unconsolidated joint venture	59,370	0	0
Interest and other income	7,230	6,777	8,765
Gains (losses) from investments in securities	2,273	(653)	1,038
Interest expense	(412,849)	(432,196)	(455,743)
Losses from early extinguishments of debt	(371)	(22,040)	(10,633)
Losses from interest rate contracts	(140)	0	0
Income before gains on sales of real estate	500,998	432,016	366,527
Gains on sales of real estate	82,775	377,093	174,686
Net income	583,773	809,109	541,213
Net income attributable to noncontrolling interests
Noncontrolling interests in property partnerships	2,068	(149,855)	(30,561)
Noncontrolling interest - redeemable preferred units	0	(6)	(1,023)
Net income attributable to the Company	585,841	659,248	509,629
Preferred dividends / distributions	(10,500)	(10,500)	(10,500)
Net income attributable to the Company's common shareholders / unitholders	$ 575,341	$ 648,748	$ 499,129
Basic earnings per common share / unit attributable to the Company
Net income (in dollars per share / unit)	$ 3.36	$ 3.79	$ 2.93
Weighted average number of common shares / units outstanding (in shares / units)	171,361	171,139	170,453
Diluted earnings per common share / unit attributable to the Company
Diluted Earnings: Net income, Per Share / Unit Amount (in dollars per share / unit)	$ 3.35	$ 3.78	$ 2.92
Weighted average number of common and common equivalent shares / units outstanding (in shares / units)	171,623	171,512	170,672
Dividends/Distributions per common share/unit	$ 2.70	$ 3.85	$ 7.10

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net income		$ 569,977	$ 799,918	$ 526,057
Other comprehensive income (loss):
Effective portion of interest rate contracts		(47,144)	(10,302)	0
Amortization of interest rate contracts	[1]	3,751	2,510	2,508
Other comprehensive income (loss)		(43,393)	(7,792)	2,508
Comprehensive Income		526,584	792,126	528,565
Comprehensive income attributable to noncontrolling interests		(57,192)	(216,812)	(82,446)
Other comprehensive income (loss) attributable to noncontrolling interests		5,256	2,982	(256)
Comprehensive income attributable to the Company		474,648	578,296	445,863
Boston Properties Limited Partnership
Net income		583,773	809,109	541,213
Other comprehensive income (loss):
Effective portion of interest rate contracts		(47,144)	(10,302)	0
Amortization of interest rate contracts	[2]	3,751	2,510	2,508
Other comprehensive income (loss)		(43,393)	(7,792)	2,508
Comprehensive Income		540,380	801,317	543,721
Comprehensive income attributable to noncontrolling interests		2,945	(147,433)	(31,584)
Comprehensive income attributable to the Company		$ 543,325	$ 653,884	$ 512,137
[1]	Amounts reclassified from comprehensive income primarily to interest expense within Boston Properties, Inc.’s Consolidated Statements of Operations
[2]	Amounts reclassified from comprehensive income primarily to interest expense within Boston Properties Limited Partnership's Consolidated Statements of Operations.

Consolidated Statements Of Stoc

Consolidated Statements Of Stockholders' Equity - USD ($) $ in Thousands	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 Loss [Member]	Noncontrolling Interests [Member]
Equity, value at Dec. 31, 2013	$ 7,043,618	$ 1,530		$ 5,662,453	$ (108,552)	$ (2,722)	$ (11,556)	$ 1,302,465
Equity, shares at Dec. 31, 2013		152,983,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of operating partnership units to Common Stock, shares		80,000
Conversion of operating partnership units to Common Stock, value	0	$ 1		2,699				(2,700)
Conversion of redeemable preferred units to common units	33,306							33,306
Allocated net income for the year	513,951				443,611			70,340
Dividends/distributions declared	(1,224,471)				(1,097,523)			(126,948)
Shares issued in connection with exchange of exchangeable senior notes, value		$ 0
Shares issued pursuant to stock purchase plan, shares		7,000
Shares issued pursuant to stock purchase plan, value	761			761
Net activity from stock option and incentive plan, shares		44,000
Net activity from stock option and incentive plan, value	27,999			6,822				21,177
Sale of interest in property partnerships and contributions from noncontrolling interest in property partnerships	1,536,382			648,407				887,975
Distributions to noncontrolling interests in property partnerships	(31,118)							(31,118)
Amortization of interest rate contracts	2,508						2,252	256
Conversion of redeemable partnership units	0			(50,885)				50,885
Equity, value at Dec. 31, 2014	7,902,936	$ 1,531	$ 200,000	6,270,257	(762,464)	(2,722)	(9,304)	2,205,638
Equity, shares at Dec. 31, 2014		153,114,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of operating partnership units to Common Stock, shares		424,000
Conversion of operating partnership units to Common Stock, value	0	$ 5		14,338				(14,343)
Allocated net income for the year	794,791				583,106			211,685
Dividends/distributions declared	(671,041)				(601,594)			(69,447)
Shares issued pursuant to stock purchase plan, shares		6,000
Shares issued pursuant to stock purchase plan, value	780			780
Net activity from stock option and incentive plan, shares		36,000
Net activity from stock option and incentive plan, value	40,265			5,814				34,451
Acquisition of redeemable noncontrolling interest in property partnership	(1,586)			(1,586)				1,053
Sale of an interest in property partnerships	0			(1,053)
Proceeds from Noncontrolling Interests	2,705							2,705
Distributions to noncontrolling interests in property partnerships	(170,049)							(170,049)
Dissolution of a property partnership	(4,082)							(4,082)
Effective portion of interest rate contracts	(10,302)						(7,061)	(3,241)
Amortization of interest rate contracts	2,510						2,251	259
Conversion of redeemable partnership units	0			17,137				(17,137)
Equity, value at Dec. 31, 2015	$ 7,886,927	$ 1,536	200,000	6,305,687	(780,952)	(2,722)	(14,114)	2,177,492
Equity, shares at Dec. 31, 2015	153,579,966	153,580,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Conversion of operating partnership units to Common Stock, shares		191,000
Conversion of operating partnership units to Common Stock, value	$ 0	$ 2		6,459				(6,461)
Allocated net income for the year	569,977				512,785			57,192
Dividends/distributions declared	(474,614)				(425,527)			(49,087)
Shares issued pursuant to stock purchase plan, shares		6,000
Shares issued pursuant to stock purchase plan, value	730			730
Net activity from stock option and incentive plan, shares		13,000
Net activity from stock option and incentive plan, value	31,910			3,979				27,931
Sale of an interest in property partnerships	0			1,195				(1,195)
Proceeds from Noncontrolling Interests	11,951							11,951
Distributions to noncontrolling interests in property partnerships	(51,564)							(51,564)
Effective portion of interest rate contracts	(47,144)						(41,502)	(5,642)
Amortization of interest rate contracts	3,751						3,365	386
Conversion of redeemable partnership units	0			15,374				(15,374)
Equity, value at Dec. 31, 2016	$ 7,931,924	$ 1,538	$ 200,000	$ 6,333,424	$ (693,694)	$ (2,722)	$ (52,251)	$ 2,145,629
Equity, shares at Dec. 31, 2016	153,790,175	153,790,000

Consolidated Statement of Partn

Consolidated Statement of Partners' Capital Statement - USD ($) $ in Thousands	Total	Boston Properties Limited Partnership
Beginning balance at Dec. 31, 2013		$ 4,187,171
Increase (Decrease) in Partners' Capital [Roll Forward]
Contributions		652,692
Net income allocable to general and limited partner units		458,767
Distributions		(1,097,523)
Other comprehensive Income (loss)		2,252
Unearned compensation		3,298
Conversion of redeemable partnership units		2,700
Adjustment to reflect redeemable partnership units at redemption value		(569,441)
Ending Balance at Dec. 31, 2014		3,639,916
Increase (Decrease) in Partners' Capital [Roll Forward]
Contributions		4,071
Acquisition of redeemable noncontrolling interest in property partnership	$ (1,586)	(1,586)
Net income allocable to general and limited partner units		592,297
Distributions		(601,594)
Other comprehensive Income (loss)		(4,810)
Unearned compensation		1,470
Conversion of redeemable partnership units		14,343
Adjustment to reflect redeemable partnership units at redemption value		40,415
Ending Balance at Dec. 31, 2015		3,684,522
Increase (Decrease) in Partners' Capital [Roll Forward]
Contributions		3,144
Net income allocable to general and limited partner units		526,581
Distributions		(425,527)
Other comprehensive Income (loss)		(38,137)
Unearned compensation		2,760
Conversion of redeemable partnership units		6,461
Adjustment to reflect redeemable partnership units at redemption value		51,913
Ending Balance at Dec. 31, 2016		$ 3,811,717

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net income	$ 569,977	$ 799,918	$ 526,057
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	694,403	639,542	628,573
Impairment loss	1,783	0	0
Non-cash compensation expense	32,911	29,183	28,099
Income from unconsolidated joint ventures	(8,074)	(22,770)	(12,769)
Gain on sale of investment in unconsolidated joint venture	(59,370)	0	0
Distributions of net cash flow from operations of unconsolidated joint ventures	24,955	8,469	7,372
Losses (gains) on investments in securities	(2,273)	653	(1,038)
Non-cash portion of interest expense	(35,052)	(42,271)	(39,343)
Settlement of accreted debt discount on repurchases/repayments of unsecured senior notes and unsecured exchangeable senior notes	0	0	(94,963)
Losses from early extinguishments of debt	371	21,837	0
Gains on sales of real estate	(80,606)	(375,895)	(168,039)
Change in assets and liabilities:
Cash held in escrows	2,277	(18,284)	3,433
Tenant and other receivables, net	3,688	(46,326)	12,869
Accrued rental income, net	(28,127)	(73,911)	(57,899)
Prepaid expenses and other assets	52,923	(16,877)	20,238
Accounts payable and accrued expenses	15,666	(6,310)	3,903
Accrued interest payable	53,547	26,854	(3,991)
Other liabilities	(106,022)	(34,005)	(57,873)
Tenant leasing costs	(96,103)	(90,396)	(99,076)
Total adjustments	466,897	(507)	169,496
Net cash provided by operating activities	1,036,874	799,411	695,553
Cash flows from investing activities:
Acquisitions of real estate	(78,000)	0	(4,670)
Construction in progress	(500,350)	(374,664)	(405,942)
Building and other capital improvements	(150,640)	(112,755)	(82,479)
Tenant improvements	(230,298)	(144,572)	(106,003)
Proceeds from sales of real estate	122,750	602,600	419,864
Proceeds from sales of real estate and sales of interests in property partnerships placed in escrow	(122,647)	(200,612)	(1,912,347)
Proceeds from sales of real estate and sales of interests in property partnerships released from escrow	122,647	634,165	1,478,794
Cash placed in escrow for land sale contracts	0	(7,111)	0
Cash released from scrow for land sale contracts	1,596	5,312	0
Cash released from escrow for investing activities	6,694	0	0
Capital contributions to unconsolidated joint ventures	(575,795)	(38,207)	(52,052)
Capital distributions from unconsolidated joint ventures	20,440	24,527	1,491
Proceeds from sale of investment in unconsolidated joint venture	55,707	0	0
Investments in marketable securities	0	(667,335)	0
Investments in securities, net	(1,161)	(1,574)	(1,780)
Net cash used in investing activities	(1,329,057)	(280,226)	(665,124)
Cash flows from financing activities:
Repayments of mortgage notes payable	(1,326,865)	(54,801)	(87,758)
Proceeds from unsecured senior notes	1,989,790	0	0
Redemption/repurchase of unsecured senior notes	0	0	(548,016)
Redemption/repurchase of unsecured exchangeable senior notes	0	0	(654,521)
Borrowings on unsecured line of credit	25,000	0	0
Repayments of unsecured line of credit	(25,000)	0	0
Payments on capital lease obligations	(745)	(356)	0
Proceeds from real estate financing transaction	0	6,000	14,523
Payments on real estate financing transactions	(5,260)	(3,103)	(234)
Deferred financing costs	(16,121)	(1,510)	(31)
Net proceeds from equity transactions	(271)	799	1,923
Redemption of preferred units	0	(633)	(17,373)
Dividends and distributions	(671,626)	(1,226,199)	(840,264)
Sales of interests in property partnerships and contributions from noncontrolling interests in property partnerships	11,951	2,705	1,536,382
Acquisition of noncontrolling interest in property partnership	0	(108,499)	0
Distributions to noncontrolling interest in property partnerships	(55,474)	(172,949)	(37,118)
Net cash used in financing activities	(74,621)	(1,558,546)	(632,487)
Net decrease in cash and cash equivalents	(366,804)	(1,039,361)	(602,058)
Cash and cash equivalents, beginning of year	723,718	1,763,079	2,365,137
Cash and cash equivalents, end of year	356,914	723,718	1,763,079
Supplemental disclosures:
Cash paid for interest	433,591	481,826	646,516
Interest capitalized	39,237	34,213	52,476
Non-cash investing and financing activities:
Write off of fully depreciated real estate	(206,721)	(45,455)	(46,943)
Change in real estate included in accounts payable and accrued expenses	(1,481)	74,985	(1,431)
Real estate acquired through capital lease	21,000	0	0
Marketable securities transferred in connection with the legal defeasance of mortgage note payable	0	667,335	0
Mortgage note payable legally defeased	0	640,500	0
Mortgage note payable assigned in connection with the sale of real estate	0	116,993	0
Dividends and distributions declared but not paid	130,308	327,320	882,472
Conversions of redeemable partnership units to partners’ capital / stockholders equity	6,461	14,343	2,700
Conversion of redeemable preferred units to common units	0	0	33,306
Issuance of restricted securities to employees and directors	33,615	43,355	27,445
Boston Properties Limited Partnership
Net income	583,773	809,109	541,213
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	682,776	631,549	620,064
Impairment loss	1,783	0	0
Non-cash compensation expense	32,911	29,183	28,099
Income from unconsolidated joint ventures	(8,074)	(22,770)	(12,769)
Gain on sale of investment in unconsolidated joint venture	(59,370)	0	0
Distributions of net cash flow from operations of unconsolidated joint ventures	24,955	8,469	7,372
Losses (gains) on investments in securities	(2,273)	653	(1,038)
Non-cash portion of interest expense	(35,052)	(42,271)	(39,343)
Settlement of accreted debt discount on repurchases/repayments of unsecured senior notes and unsecured exchangeable senior notes	0	0	(94,963)
Losses from early extinguishments of debt	371	21,837	0
Gains on sales of real estate	(82,775)	(377,093)	(174,686)
Change in assets and liabilities:
Cash held in escrows	2,277	(18,284)	3,433
Tenant and other receivables, net	3,688	(46,326)	12,869
Accrued rental income, net	(28,127)	(73,911)	(57,899)
Prepaid expenses and other assets	52,923	(16,877)	20,238
Accounts payable and accrued expenses	15,666	(6,310)	3,903
Accrued interest payable	53,547	26,854	(3,991)
Other liabilities	(106,022)	(34,005)	(57,873)
Tenant leasing costs	(96,103)	(90,396)	(99,076)
Total adjustments	453,101	(9,698)	154,340
Net cash provided by operating activities	1,036,874	799,411	695,553
Cash flows from investing activities:
Acquisitions of real estate	(78,000)	0	(4,670)
Construction in progress	(500,350)	(374,664)	(405,942)
Building and other capital improvements	(150,640)	(112,755)	(82,479)
Tenant improvements	(230,298)	(144,572)	(106,003)
Proceeds from sales of real estate	122,750	602,600	419,864
Proceeds from sales of real estate and sales of interests in property partnerships placed in escrow	(122,647)	(200,612)	(1,912,347)
Proceeds from sales of real estate and sales of interests in property partnerships released from escrow	122,647	634,165	1,478,794
Cash placed in escrow for land sale contracts	0	(7,111)	0
Cash released from scrow for land sale contracts	1,596	5,312	0
Cash released from escrow for investing activities	6,694	0	0
Capital contributions to unconsolidated joint ventures	(575,795)	(38,207)	(52,052)
Capital distributions from unconsolidated joint ventures	20,440	24,527	1,491
Proceeds from sale of investment in unconsolidated joint venture	55,707	0	0
Investments in marketable securities	0	(667,335)	0
Investments in securities, net	(1,161)	(1,574)	(1,780)
Net cash used in investing activities	(1,329,057)	(280,226)	(665,124)
Cash flows from financing activities:
Repayments of mortgage notes payable	(1,326,865)	(54,801)	(87,758)
Proceeds from unsecured senior notes	1,989,790	0	0
Redemption/repurchase of unsecured senior notes	0	0	(548,016)
Redemption/repurchase of unsecured exchangeable senior notes	0	0	(654,521)
Borrowings on unsecured line of credit	25,000	0	0
Repayments of unsecured line of credit	(25,000)	0	0
Payments on capital lease obligations	(745)	(356)	0
Proceeds from real estate financing transaction	0	6,000	14,523
Payments on real estate financing transactions	(5,260)	(3,103)	(234)
Deferred financing costs	(16,121)	(1,510)	(31)
Net proceeds from equity transactions	(271)	799	1,923
Redemption of preferred units	0	(633)	(17,373)
Dividends and distributions	(671,626)	(1,226,199)	(840,264)
Sales of interests in property partnerships and contributions from noncontrolling interests in property partnerships	11,951	2,705	1,536,382
Acquisition of noncontrolling interest in property partnership	0	(108,499)	0
Distributions to noncontrolling interest in property partnerships	(55,474)	(172,949)	(37,118)
Net cash used in financing activities	(74,621)	(1,558,546)	(632,487)
Net decrease in cash and cash equivalents	(366,804)	(1,039,361)	(602,058)
Cash and cash equivalents, beginning of year	723,718	1,763,079	2,365,137
Cash and cash equivalents, end of year	356,914	723,718	1,763,079
Supplemental disclosures:
Cash paid for interest	433,591	481,826	646,516
Interest capitalized	39,237	34,213	52,476
Non-cash investing and financing activities:
Write off of fully depreciated real estate	(202,388)	(45,455)	(46,419)
Change in real estate included in accounts payable and accrued expenses	(1,481)	74,985	(1,431)
Real estate acquired through capital lease	21,000	0	0
Marketable securities transferred in connection with the legal defeasance of mortgage note payable	0	667,335	0
Mortgage note payable legally defeased	0	640,500	0
Mortgage note payable assigned in connection with the sale of real estate	0	116,993	0
Dividends and distributions declared but not paid	130,308	327,320	882,472
Conversions of redeemable partnership units to partners’ capital / stockholders equity	6,461	14,343	2,700
Conversion of redeemable preferred units to common units	0	0	33,306
Issuance of restricted securities to employees and directors	$ 33,615	$ 43,355	$ 27,445

Organization

Organization	12 Months Ended
	Dec. 31, 2016
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 December 31, 2016 owned an approximate 89.5% ( 89.5% at December 31, 2015 ) 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 such OP Unit for cash equal to the value of a share of common stock of Boston Properties, Inc. (“Common Stock”) at such time. In lieu of a cash redemption, Boston Properties, Inc. may elect to acquire such 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 and 2016 multi-year, long-term incentive program awards (also referred to as “2013 MYLTIP Units,” “2014 MYLTIP Units,” “2015 MYLTIP Units” and “2016 MYLTIP Units,” respectively, and collectively 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 and 2013 MYLTIP Units expired on February 6, 2015 and February 4, 2016, 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 2014, 2015 and 2016 MYLTIP Units differ from other LTIP Units granted to employees (including, as of February 6, 2015, the 2012 OPP Units and, as of February 4, 2016, the 2013 MYLTIP Units). Therefore, unless specifically noted otherwise, all references to LTIP Units exclude the 2014, 2015 and 2016 MYLTIP Units. LTIP Units (including the 2012 OPP Units and the 2013 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 11 , 17 and 20 ). At December 31, 2016 , 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 its 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 12 ). Properties At December 31, 2016 , the Company owned or had interests in a portfolio of 174 commercial real estate properties (the “Properties”) aggregating approximately 47.7 million net rentable square feet of primarily Class A office properties, including eight properties under construction/redevelopment totaling approximately 4.0 million net rentable square feet. At December 31, 2016 , the Properties consisted of: • 164 Office properties (including six properties under construction/redevelopment); • one hotel; • five retail properties; and • four residential properties (including two properties under construction). 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 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. Variable Interest Entities (VIEs) On January 1, 2016, the Company adopted Accounting Standards Update (“ASU”) ASU 2015-02, “Consolidation (Topic 810): Amendments to the Consolidation Analysis” (“ASU 2015-02”). ASU 2015-02 affects reporting entities that are required to evaluate whether they should consolidate certain legal entities. ASU 2015-02 (1) modifies the evaluation of whether limited partnerships and similar legal entities are VIEs or voting interest entities, (2) eliminates the presumption that a general partner should consolidate a limited partnership and (3) affects the consolidation analysis of reporting entities that are involved with VIEs, particularly those that have fee arrangements and related party relationships. The Company reviewed all of its legal entities in accordance with ASU 2015-02 and concluded that certain of its legal entities, including Boston Properties Limited Partnership, which had been consolidated in accordance with the voting interest model, are now variable interest entities under the VIE model, as discussed below. The adoption of the guidance did not alter any of the Company’s consolidation conclusions, but resulted in additional disclosures. Consolidated VIEs are those where 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 seven of the eight entities that are VIEs. Consolidated Variable Interest Entities As of December 31, 2016 , Boston Properties, Inc. has identified seven consolidated VIEs, including Boston Properties Limited Partnership. Excluding Boston Properties Limited Partnership, the VIEs are (1) the following 5 in-service properties: 767 Fifth Avenue (the General Motors Building), Time Square Tower, 601 Lexington Avenue, Atlantic Wharf Office Building and 100 Federal Street and (2) the entity that owns Salesforce Tower, which is currently under development. The Company consolidates these VIEs as it is the primary beneficiary. The third parties’ interests in these consolidated entities, with the exception of Boston Properties Limited Partnership, are reflected as noncontrolling interests in property partnerships in the accompanying Consolidated Financial Statements (See Note 11 ). In addition, Boston Properties, Inc.’s 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. All of Boston Properties, Inc.’s debt is an obligation of Boston Properties Limited Partnership. Variable Interest Entities Not Consolidated The Company has determined that its BNY Tower Holdings LLC joint venture, which owns Dock 72 at the Brooklyn Navy Yard, is a VIE. The Company does not consolidate this entity 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.

Summary Of Significant Accounti

Summary Of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Basis Of Presentation And Summary Of Significant Accounting Policies	2. Summary of Significant Accounting Policies Real Estate Upon acquisitions of real estate that constitutes a business, which includes the consolidation of previously unconsolidated joint ventures, the Company assesses the fair value of acquired tangible and intangible assets (including land, buildings, tenant improvements, “above-” and “below-market” leases, leasing and assumed financing origination costs, acquired in-place leases, other identified intangible assets and assumed liabilities) and allocates the purchase price to the acquired assets and assumed liabilities, including land and buildings as if vacant. The Company assesses and considers fair value based on estimated cash flow projections that utilize discount and/or capitalization rates that it deems appropriate, as well as available market information. Estimates of future cash flows are based on a number of factors including the historical operating results, known and anticipated trends, and market and economic conditions. The fair value of the tangible assets of an acquired property considers the value of the property as if it were vacant. The Company also considers an allocation of purchase price of other acquired intangibles, including acquired in-place leases that may have a customer relationship intangible value, including (but not limited to) the nature and extent of the existing relationship with the tenants, the tenants’ credit quality and expectations of lease renewals. Based on its acquisitions to date, the Company’s allocation to customer relationship intangible assets has been immaterial. The Company records acquired “above-” and “below-market” leases at their fair values (using a discount rate which reflects the risks associated with the leases acquired) equal to the difference between (1) the contractual amounts to be paid pursuant to each in-place lease and (2) management’s estimate of fair market lease rates for each corresponding in-place lease, measured over a period equal to the remaining term of the lease for above-market leases and the initial term plus the term of any below-market fixed rate renewal options for below-market leases. Acquired “above-” and “below-market” lease values have been reflected within Prepaid Expenses and Other Assets and Other Liabilities, respectively, in the Company’s Consolidated Balance Sheets. Other intangible assets acquired include amounts for in-place lease values that are based on the Company’s evaluation of the specific characteristics of each tenant’s lease. Factors to be considered include estimates of carrying costs during hypothetical expected lease-up periods considering current market conditions, and costs to execute similar leases. In estimating carrying costs, the Company includes real estate taxes, insurance and other operating expenses and estimates of lost rentals at market rates during the expected lease-up periods, depending on local market conditions. In estimating costs to execute similar leases, the Company considers leasing commissions, legal and other related expenses. Management reviews its long-lived assets for impairment following the end of each quarter and when there is an event or change in circumstances that indicates an impairment in value. An impairment loss is recognized if the carrying amount of an asset is not recoverable and exceeds its fair value. The evaluation of anticipated cash flows is highly subjective and is based in part on assumptions regarding future occupancy, rental rates and capital requirements that could differ materially from actual results in future periods. Because cash flows on properties considered to be “long-lived assets to be held and used” are considered on an undiscounted basis to determine whether an asset has been impaired, the Company’s established strategy of holding properties over the long term directly decreases the likelihood of recording an impairment loss. If the Company’s strategy changes or market conditions otherwise dictate an earlier sale date, an impairment loss may be recognized and such loss could be material. If the Company determines that an impairment has occurred, the affected assets must be reduced to their fair value, less cost to sell. Guidance in Accounting Standards Codification (“ASC”) 360 “Property Plant and Equipment” (“ASC 360”) requires that qualifying assets and liabilities and the results of operations that have been sold, or otherwise qualify as “held for sale,” be presented as discontinued operations in all periods presented if the property operations are expected to be eliminated and the Company will not have significant continuing involvement following the sale. The components of the property’s net income that are reflected as discontinued operations include the net gain (or loss) upon the disposition of the property held for sale, operating results, depreciation and interest expense (if the property is subject to a secured loan). The Company generally considers assets to be “held for sale” when the transaction has been approved by Boston Properties, Inc.’s Board of Directors, or a committee thereof, and there are no known significant contingencies relating to the sale, such that a sale of the property within one year is considered probable. Following the classification of a property as “held for sale,” no further depreciation is recorded on the assets, and the asset is written down to the lower of carrying value or fair market value, less cost to sell. On April 10, 2014, the Financial Accounting Standards Board (“FASB”) issued ASU 2014-08, “Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity” (“ASU 2014-08”). ASU 2014-08 clarifies that discontinued operations presentation applies only to disposals representing a strategic shift that has (or will have) a major effect on an entity’s operations and financial results (e.g., a disposal of a major geographical area, a major line of business, a major equity method investment or other major parts of an entity). ASU 2014-08 is effective prospectively for reporting periods beginning after December 15, 2014. Early adoption is permitted, and the Company early adopted ASU 2014-08 during the first quarter of 2014. The Company’s adoption of ASU 2014-08 resulted in the operating results and gains on sales of real estate from operating properties sold during the years ended December 31, 2016, 2015 and 2014 not being reflected within Discontinued Operations in the Company’s Consolidated Statements of Operations (See Note 3 ). Real estate is stated at depreciated cost. A variety of costs are incurred in the acquisition, development and leasing of properties. The cost of buildings and improvements includes the purchase price of property, legal fees and other acquisition costs. The Company expenses costs that it incurs to effect a business combination such as legal, due diligence and other closing related costs. Costs directly related to the development of properties are capitalized. Capitalized development costs include interest, internal wages, property taxes, insurance, and other project costs incurred during the period of development. After the determination is made to capitalize a cost, it is allocated to the specific component of a project that is benefited. Determination of when a development project commences and capitalization begins, and when a development project is substantially complete and held available for occupancy and capitalization must cease, involves a degree of judgment. The Company’s capitalization policy on development properties is follows the guidance in ASC 835-20 “Capitalization of Interest” and ASC 970 “Real Estate-General.” The costs of land and buildings under development include specifically identifiable costs. The capitalized costs include pre-construction costs necessary to the development of the property, development costs, construction costs, interest costs, real estate taxes, salaries and related costs and other costs incurred during the period of development. The Company begins the capitalization of costs during the pre-construction period which it defines as activities that are necessary for the development of the property. The Company considers a construction project as substantially completed and held available for occupancy upon the completion of tenant improvements, but no later than one year from cessation of major construction activity. The Company ceases capitalization on the portion (1) substantially completed, (2) occupied or held available for occupancy, and capitalizes only those costs associated with the portion under construction or (3) if activities necessary for the development of the property have been suspended. Interest costs capitalized for the years ended December 31, 2016 , 2015 and 2014 were $39.2 million , $34.2 million and $52.5 million , respectively. Salaries and related costs capitalized for the years ended December 31, 2016 , 2015 and 2014 were $11.1 million , $10.4 million and $8.5 million , respectively. Expenditures for repairs and maintenance are charged to operations as incurred. Significant betterments are capitalized. When assets are sold or retired, their costs and related accumulated depreciation are removed from the accounts with the resulting gains or losses reflected in net income or loss for the period. The Company computes depreciation and amortization on properties using the straight-line method based on estimated useful asset lives. In accordance with ASC 805 “Business Combinations,” the Company allocates the acquisition cost of real estate to its components and depreciates or amortizes these assets (or liabilities) over their useful lives. The amortization of acquired “above-” and “below-market” leases and acquired in-place leases is recorded as an adjustment to revenue and depreciation and amortization, respectively, in the Consolidated Statements of Operations. Depreciation is computed on a straight-line basis over the estimated useful lives of the assets as follows: Land improvements 25 to 40 years Buildings and improvements 10 to 40 years Tenant improvements Shorter of useful life or terms of related lease Furniture, fixtures, and equipment 3 to 7 years Cash and Cash Equivalents Cash and cash equivalents consist of cash on hand and investments with maturities of three months or less from the date of purchase. The majority of the Company’s cash and cash equivalents are held at major commercial banks which may at times exceed the Federal Deposit Insurance Corporation limit of $250,000 . The Company has not experienced any losses to date on its invested cash. Cash Held in Escrows Escrows include amounts established pursuant to various agreements for security deposits, property taxes, insurance and other costs. Escrows also include cash held by qualified intermediaries for possible investments in like-kind exchanges in accordance with Section 1031 of the Internal Revenue Code in connection with sales of the Company’s properties. Investments in Securities The Company accounts for investments in trading securities at fair value, with gains or losses resulting from changes in fair value recognized currently in earnings. The designation of trading securities is generally determined at acquisition. The Company maintains a deferred compensation plan that is designed to allow officers of Boston Properties, Inc. to defer a portion of their current income on a pre-tax basis and receive a tax-deferred return on these deferrals. The Company’s obligation under the plan is that of an unsecured promise to pay the deferred compensation to the plan participants in the future. At December 31, 2016 and 2015 , the Company had maintained approximately $23.8 million and $20.4 million , respectively, in a separate account, which is not restricted as to its use. The Company recognized gains (losses) of approximately $2.3 million , $(0.7) million and $1.0 million on its investments in the account associated with the Company’s deferred compensation plan during the years ended December 31, 2016 , 2015 and 2014 , respectively. Tenant and Other Receivables Tenant and other accounts receivable, other than accrued rents receivable, are expected to be collected within one year. Deferred Charges Deferred charges include leasing costs and financing fees. Leasing costs include acquired intangible in-place lease values and direct and incremental fees and costs incurred in the successful negotiation of leases, including brokerage, legal, internal leasing employee salaries and other costs which have been deferred and are being amortized on a straight-line basis over the terms of the respective leases. Internal leasing salaries and related costs capitalized for the years ended December 31, 2016 , 2015 and 2014 were $7.2 million , $5.5 million and $6.0 million , respectively. External fees and costs incurred to obtain long-term financing have been deferred and are being amortized over the terms of the respective loans and are included within interest expense. Unamortized financing and leasing costs are charged to expense upon the early repayment or significant modification of the financing or upon the early termination of the lease, respectively. Fully amortized deferred charges are removed from the books upon the expiration of the lease or maturity of the debt. On January 1, 2016, the Company adopted ASU 2015-03 “Interest - Imputation of Interst (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs” and retrospectively applied the guidance to its Mortgage Notes Payable and Unsecured Senior Notes for all periods presented (See Note 4 ). Unamortized deferred financing costs, which were previously included in Deferred Charges, Net, totaling approximately $2.4 million and $35.3 million are included in Mortgage Notes Payable, Net and Unsecured Senior Notes, Net, respectively, as of December 31, 2016 and approximately $3.5 million and $24.5 million are included in Mortgage Notes Payable, Net and Unsecured Senior Notes, Net, respectively, as of December 31, 2015. Net unamortized deferred financing costs associated with the Company’s Unsecured Line of Credit totaling approximately $1.9 million and $3.1 million as of December 31, 2016 and 2015, respectively, continue to be presented within Deferred Charges, Net as there is no balance outstanding. Investments in Unconsolidated Joint Ventures The Company consolidates VIEs in which it is considered to be the primary beneficiary. VIEs are entities in which the equity investors do not have sufficient equity at risk to finance their endeavors without additional financial support or that the holders of the equity investment at risk do not have substantive participating rights. The primary beneficiary 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 variable interest entity’s performance, and (2) the obligation to absorb losses and the right to receive the returns from the variable interest entity that could potentially be significant to the VIE. For ventures that are not VIEs, the Company consolidates entities for which it has significant decision making control over the ventures’ operations. The Company’s judgment with respect to its level of influence or control of an entity involves the consideration of various factors including the form of the Company’s ownership interest, its representation in the entity’s governance, the size of its investment (including loans), estimates of future cash flows, its ability to participate in policy making decisions and the rights of the other investors to participate in the decision making process and to replace the Company as manager and/or liquidate the venture, if applicable. The Company’s assessment of its influence or control over an entity affects the presentation of these investments in the Company’s consolidated financial statements. In addition to evaluating control rights, the Company consolidates entities in which the outside partner has no substantive kick-out rights to remove the Company as the managing member. Accounts of the consolidated entity are included in the accounts of the Company and the noncontrolling interest is reflected on the Consolidated Balance Sheets as a component of equity or in temporary equity between liabilities and equity. Investments in unconsolidated joint ventures are recorded initially at cost, and subsequently adjusted for equity in earnings and cash contributions and distributions. Any difference between the carrying amount of these investments on the balance sheet and the underlying equity in net assets is amortized as an adjustment to equity in earnings of unconsolidated joint ventures over the life of the related asset. Under the equity method of accounting, the net equity investment of the Company is reflected within the Consolidated Balance Sheets, and the Company’s share of net income or loss from the joint ventures is included within the Consolidated Statements of Operations. The joint venture agreements may designate different percentage allocations among investors for profits and losses; however, the Company’s recognition of joint venture income or loss generally follows the joint venture’s distribution priorities, which may change upon the achievement of certain investment return thresholds. The Company may account for cash distributions in excess of its investment in an unconsolidated joint venture as income when the Company is not the general partner in a limited partnership and when the Company has neither the requirement nor the intent to provide financial support to the joint venture. The Company’s investments in unconsolidated joint ventures are reviewed for impairment periodically and the Company records impairment charges when events or circumstances change indicating that a decline in the fair values below the carrying values has occurred and such decline is other-than-temporary. The ultimate realization of the investment in unconsolidated joint ventures is dependent on a number of factors, including the performance of each investment and market conditions. The Company will record an impairment charge if it determines that a decline in the value below the carrying value of an investment in an unconsolidated joint venture is other-than-temporary. To the extent that the Company contributes assets to a joint venture, the Company’s investment in the joint venture is recorded at the Company’s cost basis in the assets that were contributed to the joint venture. To the extent that the Company’s cost basis is different than the basis reflected at the joint venture level, the basis difference is amortized over the life of the related asset and included in the Company’s share of equity in net income of the joint venture. In accordance with the provisions of ASC 970-323 “Investments—Equity Method and Joint Ventures” (“ASC 970-323”), the Company will recognize gains on the contribution of real estate to joint ventures, relating solely to the outside partner’s interest, to the extent the economic substance of the transaction is a sale. The combined summarized financial information of the unconsolidated joint ventures is disclosed in Note 5 . Revenue Recognition In general, the Company commences rental revenue recognition when the tenant takes possession of the leased space and the leased space is substantially ready for its intended use. Contractual rental revenue is reported on a straight-line basis over the terms of the respective leases. The impact of the straight-line rent adjustment increased revenue by approximately $31.7 million , $80.0 million and $63.1 million for the years ended December 31, 2016 , 2015 and 2014 , respectively, as the revenue recorded exceeded amounts billed. Accrued rental income, as reported on the Consolidated Balance Sheets, represents cumulative rental income earned in excess of rent payments received pursuant to the terms of the individual lease agreements. The Company maintains an allowance against accrued rental income for future potential tenant credit losses. The credit assessment is based on the estimated accrued rental income that is recoverable over the term of the lease. The Company also maintains an allowance for doubtful accounts for estimated losses resulting from the inability of tenants to make required rent payments. The computation of this allowance is based on the tenants’ payment history and current credit status, as well as certain industry or geographic specific credit considerations. If the Company’s estimates of collectability differ from the cash received, then the timing and amount of the Company’s reported revenue could be impacted. The credit risk is mitigated by the high quality of the Company’s existing tenant base, reviews of prospective tenants’ risk profiles prior to lease execution and consistent monitoring of the Company’s portfolio to identify potential problem tenants. In accordance with ASC 805, the Company recognizes acquired in-place “above-” and “below-market” leases at their fair values as rental revenue over the original term of the respective leases. The impact of the acquired in-place “above-” and “below-market” leases increased revenue by approximately $30.2 million , $35.9 million and $48.3 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. The following table summarizes the scheduled amortization of the Company’s acquired “above-” and “below-market” lease intangibles for each of the five succeeding years (in thousands). Acquired Above-Market Lease Intangibles Acquired Below-Market Lease Intangibles 2017 $ 11,697 $ 33,871 2018 8,609 32,156 2019 7,100 27,318 2020 5,394 10,736 2021 2,988 6,294 Recoveries from tenants, consisting of amounts due from tenants for common area maintenance, real estate taxes and other recoverable costs, are recognized as revenue in the period during which the expenses are incurred. Tenant reimbursements are recognized and presented in accordance with guidance in ASC 605-45 “Principal Agent Considerations” (“ASC 605-45”). ASC 605-45 requires that these reimbursements be recorded on a gross basis, as the Company is generally the primary obligor with respect to purchasing goods and services from third-party suppliers, has discretion in selecting the supplier and has credit risk. The Company also receives reimbursement of payroll and payroll related costs from third parties which the Company reflects on a net basis. The Company’s parking revenues are derived from leases, monthly parking and transient parking. The Company recognizes parking revenue as earned. The Company’s hotel revenue is derived from room rentals and other sources such as charges to guests for telephone service, movie and vending commissions, meeting and banquet room revenue and laundry services. Hotel revenue is recognized as earned. The Company receives management and development fees from third parties. Property management fees are recorded and earned based on a percentage of collected rents at the properties under management, and not on a straight-line basis, because such fees are contingent upon the collection of rents. The Company records development fees as earned depending on the risk associated with each project. The Company recognizes development fees earned from joint venture projects equal to its cost plus profit to the extent of the third party partners’ ownership interest. Gains on sales of real estate are recognized pursuant to the provisions included in ASC 360-20 “Real Estate Sales” (“ASC 360-20”). The specific timing of the sale is measured against various criteria in ASC 360-20 related to the terms of the transaction and any continuing involvement in the form of management or financial assistance associated with the properties. If the sales criteria for the full accrual method are not met, the Company defers some or all of the gain recognition and accounts for the continued operations of the property by applying the finance, leasing, profit sharing, deposit, installment or cost recovery methods, as appropriate, until the sales criteria are met. Ground Leases The Company has non-cancelable ground lease obligations with various initial term expiration dates through 2114 . The Company recognizes ground rent expense on a straight-line basis over the terms of the respective ground lease agreements. The future contractual minimum lease payments to be made by the Company as of December 31, 2016 , under non-cancelable ground leases which expire on various dates through 2114 , are as follows: Years Ending December 31, (in thousands) 2017 $ 12,554 2018 28,781 2019 17,868 2020 9,870 2021 9,492 Thereafter 585,209 Earnings Per Share Basic earnings per share (“EPS”) is computed by dividing net income available to common shareholders, as adjusted for undistributed earnings (if any) of certain securities issued by Boston Properties Limited Partnership, by the weighted average number of shares of Common Stock outstanding during the year. Diluted EPS reflects the potential dilution that could occur from shares issuable in connection with awards under stock-based compensation plans, including upon the exercise of stock options, and securities of Boston Properties Limited Partnership that are exchangeable for Common Stock. Earnings Per Common Unit Basic earnings per common unit is computed by dividing net income available to common unitholders, as adjusted for undistributed earnings (if any) of certain securities issued by Boston Properties Limited Partnership, by the weighted average number of common units outstanding during the year. Diluted earnings per common unit reflects the potential dilution that could occur from units issuable in connection with awards under Boston Properties, Inc.’s stock-based compensation plans, including upon the exercise of stock options, and conversion of preferred units of Boston Properties Limited Partnership. Fair Value of Financial Instruments The carrying values of cash and cash equivalents, marketable securities, escrows, receivables, accounts payable, accrued expenses and other assets and liabilities are reasonable estimates of their fair values because of the short maturities of these 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 ASC 820 "Fair Value Measurements and Disclosures", the accounting standards for Fair Value Measurements and Disclosures) 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 the accounting standards for Fair Value Measurements and Disclosures) if trading volumes are low. The Company determines the fair value of its mortgage notes payable using discounted cash flow analysis by discounting the spread between the future contractual interest payments and hypothetical future interest payments on 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 mortgage notes payable and mezzanine notes payable are categorized at a level 3 basis (as defined in the accounting standards for Fair Value Measurements and Disclosures) due to the fact that the Company considers the rates used in the valuation techniques to be unobservable inputs. 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 if the Company’s estimates do not prove to be accurate, and the Company’s estimated fair values for these instruments as of the end of the applicable reporting period are not necessarily indicative of estimated or actual fair values in future reporting periods. The following table presents the aggregate carrying value of the Company’s mortgage notes payable, net, mezzanine notes payable and unsecured senior notes, net and the Company’s corresponding estimate of fair value as of December 31, 2016 and December 31, 2015 (in thousands): December 31, 2016 December 31, 2015 Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Mortgage notes payable, net $ 2,063,087 $ 2,092,237 $ 3,435,242 $ 3,503,746 Mezzanine notes payable 307,093 308,344 308,482 306,103 Unsecured senior notes, net 7,245,953 7,428,077 5,264,819 5,547,738 Total $ 9,616,133 $ 9,828,658 $ 9,008,543 $ 9,357,587 The Company uses interest rate swap agreements to manage its interest rate risk. The valuation of these instruments is determined using widely accepted valuation techniques, including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves. To comply with the provisions of ASC 820, the Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. Although the Company has determined that the majority of the inputs used to value its derivatives fall within level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by the Company and its counterparties. However, as of December 31, 2016, the Company has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivatives. As a result, the Company has determined that its derivative valuations in their entirety are classified in level 2 of the fair value hierarchy. Derivative Instruments and Hedging Activities Derivative instruments and hedging activities require management to make judgments on the nature of its derivatives and their effectiveness as hedges. These judgments determine if the changes in fair value of the derivative instruments are reported in the Consolidated Statements of Operations as a component of net income or as a component of comprehensive income and as a component of equity on the Consolidated Balance Sheets. While management believes its judgments are reasonable, a change in a derivative’s effectiveness as a hedge could materially affect expenses, net income and equity. The Company accounts for the effective portion of changes in the fair value of a derivative in other comprehensive income (loss) and subsequently reclassifies the effective portion to earnings over the term that the hedged transaction affects earnings. The Company accounts for the ineffective portion of changes in the fair value of a derivative directly in earnings. Stock-Based Employee Compensation Plans At December 31, 2016 , the Company has a stock-based employee compensation plan. The Company accounts for the plan under the guidance in ASC 718 “Compensation – Stock Compensation” (“ASC 718”), which revised the fair value based method of accounting for share-based payment liabilities, forfeitures and modifications of stock-based awards and clarified previous guidance in several areas, including measuring fair value, classifying an award as equity or as a liability and attributing compensation cost to reporting periods. Use of Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. These estimates include such items as depreciation and allowances for doubtful accounts. Actual results could differ from those estimates. Recent Accounting Pronouncements In May 2014, th

Real Estate

Real Estate	12 Months Ended
	Dec. 31, 2016
Real Estate [Abstract]
Real Estate	3. Real Estate Boston Properties, Inc. Real estate consisted of the following at December 31 (in thousands): 2016 2015 Land $ 4,879,020 $ 4,806,021 Land held for future development (1) 246,656 252,195 Buildings and improvements 11,890,626 11,709,285 Tenant improvements 2,060,315 1,920,247 Furniture, fixtures and equipment 32,687 29,852 Construction in progress 1,037,959 763,935 Total 20,147,263 19,481,535 Less: Accumulated depreciation (4,222,235 ) (3,925,894 ) $ 15,925,028 $ 15,555,641 _______________ (1) Includes pre-development costs. Boston Properties Limited Partnership Real estate consisted of the following at December 31 (in thousands): 2016 2015 Land $ 4,774,460 $ 4,700,793 Land held for future development (1) 246,656 252,195 Buildings and improvements 11,581,795 11,394,119 Tenant improvements 2,060,315 1,920,247 Furniture, fixtures and equipment 32,687 29,852 Construction in progress 1,037,959 763,935 Total 19,733,872 19,061,141 Less: Accumulated depreciation (4,136,364 ) (3,846,816 ) $ 15,597,508 $ 15,214,325 _______________ (1) Includes pre-development costs. Acquisitions On April 22, 2016, the Company acquired 3625-3635 Peterson Way located in Santa Clara, California for a purchase price of approximately $78.0 million in cash. 3625-3635 Peterson Way is an approximately 218,000 net rentable square foot office property. The property is 100% leased to a single tenant through March 2021. Following the lease expiration, the Company intends to develop the site into a Class A office campus containing an aggregate of approximately 632,000 net rentable square feet. The following table summarizes the allocation of the aggregate purchase price of 3625-3635 Peterson Way at the date of acquisition (in thousands). Land $ 63,206 Building and improvements 7,210 Tenant improvements 7,669 In-place lease intangibles 4,262 Below-market lease intangible (4,347 ) Net assets acquired $ 78,000 The following table summarizes the estimated annual amortization of the acquired below-market lease intangible and the acquired in-place lease intangibles for 3625-3635 Peterson Way for the remainder of 2016 and each of the next four succeeding fiscal years (in thousands). Acquired In-Place Lease Intangibles Acquired Below- Market Lease Intangible Period from April 22, 2016 through December 31, 2016 $ 296 $ (589 ) 2017 444 (884 ) 2018 444 (884 ) 2019 444 (884 ) 2020 444 (884 ) 3625-3635 Peterson Way contributed approximately $3.9 million of revenue and approximately $0.2 million of earnings to the Company for the period from April 22, 2016 through December 31, 2016. Dispositions On February 1, 2016, the Company completed the sale of its 415 Main Street property located in Cambridge, Massachusetts to the tenant for a gross sale price of approximately $105.4 million . Net cash proceeds totaled approximately $104.9 million , resulting in a gain on sale of real estate totaling approximately $60.8 million for Boston Properties, Inc. and approximately $63.0 million for Boston Properties Limited Partnership. As part of its lease signed on July 14, 2004, the tenant was granted a fixed-price option to purchase the building at the beginning of the 11th lease year, which option was exercised by the tenant on October 22, 2014. 415 Main Street is an office property with approximately 231,000 net rentable square feet. 415 Main Street contributed approximately $1.2 million of net income to the Company for the period from January 1, 2016 through January 31, 2016 and contributed approximately $8.3 million and $8.2 million of net income to the Company for the years ended December 31, 2015 and 2014, respectively. On August 16, 2016, the Company completed the sale of a parcel of land within its Broad Run Business Park property located in Loudoun County, Virginia for a gross sale price of approximately $18.0 million . Net cash proceeds totaled approximately $17.9 million , resulting in a gain on sale of real estate totaling approximately $13.0 million . On September 27, 2016, the Company executed a letter of intent for the sale of the remaining parcel of land at its Washingtonian North property located in Gaithersburg, Maryland. The letter of intent caused the Company to reevaluate its strategy for the land and, based on a shorter than expected hold period, the Company reduced the carrying value of the land to the estimated net sales price and recognized an impairment loss of approximately $1.8 million during the year ended December 31, 2016. On November 14, 2016, the Company executed an agreement for the sale of the land for a sale price of approximately $7.8 million . The sale is subject to the receipt of certain approvals and the satisfaction of customary closing conditions and there can be no assurance that the sale will be consummated on the terms currently contemplated or at all. Development/Redevelopment On May 27, 2016, the Company completed and fully placed in-service 601 Massachusetts Avenue, a Class A office project with approximately 479,000 net rentable square feet located in Washington, DC. On May 27, 2016, the Company completed and fully placed in-service 804 Carnegie Center, a Class A office project with approximately 130,000 net rentable square feet located in Princeton, New Jersey. On June 24, 2016, the Company completed and fully placed in-service 10 CityPoint, a Class A office project with approximately 241,000 net rentable square feet located in Waltham, Massachusetts. On August 19, 2016, the consolidated entity in which the Company has a 55% interest and that owns 601 Lexington Avenue located in New York City commenced the redevelopment of the six -story, low-rise office and retail building component of the complex, which will be called 159 East 53rd Street. The redeveloped portion of the low-rise building will contain approximately 195,000 net rentable square feet of Class A office space and approximately 25,000 net rentable square feet of retail space. The Company will capitalize incremental costs during the redevelopment. Boston Properties, Inc. and Boston Properties Limited Partnership recognized approximately $50.8 million and $47.6 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. Approximately $21.4 million of those amounts was allocated to the outside partners and is included within Noncontrolling Interests in Property Partnerships in the Company’s Consolidated Statements of Operations. On September 16, 2016, the Company partially placed in-service 888 Boylston Street, a Class A office project with approximately 425,000 net rentable square feet located in Boston, Massachusetts. On November 7, 2016, the Company entered into a 15 -year lease with a tenant for approximately 476,500 net rentable square feet of Class A office space in a build-to-suit development project to be located at the Company’s 145 Broadway property at Kendall Center in Cambridge, Massachusetts. 145 Broadway currently consists of an approximately 80,000 net rentable square foot Class A office property that will be demolished and developed into an approximately 486,000 net rentable square foot Class A office property, including approximately 9,500 net rentable square feet of retail space. The commencement of the redevelopment project is subject to the receipt of the remaining necessary approvals, and the Company currently expects to begin the project in the second quarter of 2017 with the relocation of an existing tenant to another property within the Company’s portfolio. The Company expects the building will be available for occupancy by the new tenant during the fourth quarter of 2019. There can be no assurance that the project will commence or that the building will be available for occupancy on the anticipated schedule or at all. On December 29, 2016, the Company commenced the redevelopment of 191 Spring Street, a Class A office project with approximately 160,000 net rentable square feet located in Lexington, Massachusetts. Option and Development Agreements On October 24, 2016, the Company entered into an option agreement that will allow it to ground lease, with the future right to purchase, real property adjacent to the MacArthur BART station located in Oakland, California, that could support the development of a 400 -unit residential building and supporting retail space. On December 6, 2016, the Company entered into a development agreement with The George Washington University to pursue the development of a Class A office property with approximately 482,000 net rentable square feet on land parcels located at 2100 Pennsylvania Avenue in Washington, DC. The development agreement provides for the execution of a 75 -year ground lease for the property upon completion of the entitlement process and relocation of existing tenants anticipated to occur in 2019. The Company has made a deposit of $15.0 million that, upon execution of the ground lease, will be credited against ground rent under the ground lease. Lease Terminations On February 3, 2016, the Company entered into a lease termination agreement with a tenant for an approximately 85,000 square foot lease at its 250 West 55th Street property located in New York City. The lease was scheduled to expire on February 28, 2035. In consideration for the termination of the lease, the tenant paid the Company approximately $45.0 million , which was recognized as termination income and is included in Base Rent in the Consolidated Statements of Operations for the year ended December 31, 2016.

Deferred Charges

Deferred Charges	12 Months Ended
	Dec. 31, 2016
Deferred Charges [Abstract]
Deferred Charges	4. Deferred Charges Deferred charges consisted of the following at December 31 (in thousands): 2016 2015 Leasing costs, including lease related intangibles $ 1,132,092 $ 1,123,105 Financing costs 6,094 6,094 1,138,186 1,129,199 Less: Accumulated amortization (452,023 ) (424,332 ) $ 686,163 $ 704,867 On January 1, 2016, the Company adopted ASU 2015-03 and retrospectively applied the guidance to its Mortgage Notes Payable and Unsecured Senior Notes for all periods presented (See Note 2 ). Unamortized deferred financing costs, which were previously included in Deferred Charges, Net, totaling approximately $2.4 million and $35.3 million are included in Mortgage Notes Payable, Net and Unsecured Senior Notes, Net, respectively, as of December 31, 2016 and approximately $3.5 million and $24.5 million are included in Mortgage Notes Payable, Net and Unsecured Senior Notes, Net, respectively, as of December 31, 2015. Net unamortized deferred financing costs associated with the Company's Unsecured Line of Credit totaling approximately $1.9 million and $3.1 million as of December 31, 2016 and 2015, respectively, continue to be presented within Deferred Charges, Net as there is no balance outstanding. The following table summarizes the scheduled amortization of the Company’s acquired in-place lease intangibles for each of the five succeeding years (in thousands). Acquired In-Place Lease Intangibles 2017 $ 37,547 2018 32,831 2019 26,556 2020 13,885 2021 8,365

Investments in Unconsolidated J

Investments in Unconsolidated Joint Ventures	12 Months Ended
	Dec. 31, 2016
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 December 31, 2016 and 2015: Carrying Value of Investment (1) Entity Properties Nominal % Ownership December 31, December 31, (in thousands) Square 407 Limited Partnership Market Square North 50.0 % $ (8,134 ) $ (9,951 ) BP/CRF Metropolitan Square LLC Metropolitan Square 20.0 % (2) 2,004 9,179 901 New York LLC 901 New York Avenue 25.0 % (3) (10,564 ) (11,958 ) WP Project Developer LLC Wisconsin Place Land and Infrastructure 33.3 % (4) 41,605 43,524 Annapolis Junction NFM, LLC Annapolis Junction 50.0 % (5) 20,539 29,009 540 Madison Venture LLC 540 Madison Avenue 60.0 % 67,816 68,983 500 North Capitol LLC 500 North Capitol Street, NW 30.0 % (3,389 ) (3,292 ) 501 K Street LLC 1001 6th Street 50.0 % (6) 42,528 42,584 Podium Developer LLC The Hub on Causeway - Podium 50.0 % 29,869 18,508 Residential Tower Developer LLC The Hub on Causeway - Residential 50.0 % 20,803 N/A Hotel Tower Developer LLC The Hub on Causeway - Hotel 50.0 % 933 N/A 1265 Main Office JV LLC 1265 Main Street 50.0 % 4,779 11,916 BNY Tower Holdings LLC Dock 72 at the Brooklyn Navy Yard 50.0 % (7) 33,699 11,521 CA-Colorado Center Limited Partnership Colorado Center 49.8 % 510,623 N/A $ 753,111 $ 210,023 _______________ (1) Investments with deficit balances aggregating approximately $22.1 million and $25.2 million at December 31, 2016 and 2015, respectively, have been reflected within Other Liabilities in the Company’s Consolidated Balance Sheets. (2) On October 20, 2016, the Company sold a 31% ownership interest in this joint venture. (3) The Company’s economic ownership has increased based on the achievement of certain return thresholds. (4) The Company’s wholly-owned entity that owns the office component of the project also owns a 33.3% interest in the entity owning the land, parking garage and infrastructure of the project. (5) The joint venture owns four in-service buildings and two undeveloped land parcels. (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 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 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 ventures agreements, if certain return thresholds are achieved the partners will be entitled to an additional promoted interest or payments. The combined summarized balance sheets of the Company’s unconsolidated joint ventures are as follows: December 31, December 31, (in thousands) ASSETS Real estate and development in process, net $ 1,519,217 $ 1,072,412 Other assets 297,263 252,285 Total assets $ 1,816,480 $ 1,324,697 LIABILITIES AND MEMBERS’/PARTNERS’ EQUITY Mortgage and notes payable, net $ 865,665 $ 830,125 Other liabilities 67,167 44,549 Members’/Partners’ equity 883,648 450,023 Total liabilities and members’/partners’ equity $ 1,816,480 $ 1,324,697 Company’s share of equity $ 450,662 $ 237,070 Basis differentials (1) 302,449 (27,047 ) Carrying value of the Company’s investments in unconsolidated joint ventures (2) $ 753,111 $ 210,023 _______________ (1) 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 December 31, 2016, there is an aggregate basis differential of approximately $328.8 million 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. (2) Investments with deficit balances aggregating approximately $22.1 million and $25.2 million at December 31, 2016 and 2015 , 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: For the year ended December 31, 2016 2015 2014 (in thousands) Total revenue (1) $ 177,182 $ 155,642 $ 158,161 Expenses Operating 76,741 65,093 62,974 Depreciation and amortization 44,989 36,057 37,041 Total expenses 121,730 101,150 100,015 Operating income 55,452 54,492 58,146 Other income (expense) Interest expense (34,016 ) (32,176 ) (31,896 ) Net income $ 21,436 $ 22,316 $ 26,250 Company’s share of net income (2) $ 9,873 $ 22,031 $ 11,913 Basis differential (3) (1,799 ) 739 856 Income from unconsolidated joint ventures $ 8,074 $ 22,770 $ 12,769 Gain on sale of investment in unconsolidated joint venture $ 59,370 $ — $ — _______________ (1) Includes straight-line rent adjustments of approximately $18.1 million , $3.9 million and $3.0 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. (2) During the year ended December 31, 2015, the Company received a distribution of approximately $24.5 million , which was generated from the excess loan proceeds from the refinancing of 901 New York Avenue’s mortgage loan to a new 10 -year mortgage loan totaling $225.0 million . The Company’s allocation of income and distributions for the year ended December 31, 2015 was not proportionate to its nominal ownership interest as a result of the achievement of specified investment return thresholds, as provided for in the joint venture agreement. (3) Includes the Company’s share of straight-line rent adjustments of approximately $1.4 million and net below-market rent adjustments of approximately $0.9 million for the year ended December 31, 2016. On April 11, 2016, a joint venture in which the Company has a 50% interest received a notice of event of default from the lender for the loan collateralized by its Annapolis Junction Building One property. The event of default relates to the loan to value ratio not being in compliance with the loan agreement. The loan has an outstanding balance of approxim ately $39.6 million , is non -recourse to the Company, bears interest at a variable rate equal to LIBOR plus 1.75% per annum and has a stated maturity date of March 31, 2018, with one , three -year extension option, subject to certain conditions including that the loan is not in default . On October 17, 2016, the lender notified the joint venture that it has elected to charge the default interest rate on the loan equal to LIBOR plus 5.75% per annum. The joint venture is currently in discussions with the lender regarding the event of default, although there can be no assurance as to the outcome of those discussions. The estimated fair value of the Company’s investment in the unconsolidated joint venture exceeds its carrying value. Annapolis Junction Building One is a Class A office property with approximately 118,000 net rentable square feet located in Annapolis, Maryland. On July 1, 2016, the Company entered the Los Angeles market through its acquisition of a 49.8% interest in an existing joint venture that owns and operates Colorado Center located in Santa Monica, California for a gross purchase price of approximately $511.1 million , or approximately $503.6 million in cash net of credits for free rent, unfunded leasing costs and other adjustments. Colorado Center is a six -building office complex that sits on a 15 -acre site and contains an aggregate of approximately 1,184,000 net rentable square feet with an underground parking garage for 3,100 vehicles. The following table summarizes the allocation of the Company’s aggregate purchase price for its 49.8% interest in Colorado Center at the date of acquisition (in thousands). Land and improvements $ 189,597 Site improvements 9,050 Building and improvements 259,592 Tenant improvements 17,234 In-place lease intangibles 43,157 Above-market lease intangible 819 Below-market lease intangible (16,461 ) Net assets $ 502,988 On October 1, 2016, a joint venture in which the Company has a 50% interest completed and fully placed in-service 1265 Main Street, a Class A office project with approximately 115,000 net rentable square feet located in Waltham, Massachusetts. On December 8, 2016, the joint venture obtained mortgage financing totaling $40.4 million collateralized by the property. The mortgage loan bears interest at a fixed rate of 3.77% per annum and matures on January 1, 2032. On October 20, 2016, the Company and its partner in the unconsolidated joint venture that owns Metropolitan Square located in Washington, DC, completed the sale of an 80% interest in the joint venture for a gross sale price of approximately $282.4 million , including the assumption by the buyer of its pro rata share of the mortgage loan collateralized by the property totaling approximately $133.4 million . In addition, the buyer agreed to assume certain unfunded leasing costs totaling approximately $14.2 million . Net proceeds to the Company totaled approximately $58.2 million , resulting in a gain on sale of investment totaling approximately $59.4 million . Prior to the sale, the Company owned a 51% interest and its partner owned a 49% interest in the joint venture. Following the sale, the Company continues to own a 20% interest in the joint venture with the buyer owning the remaining 80% . Metropolitan Square is an approximately 607,000 net rentable square foot Class A office property. On November 15, 2016, 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 loan had an outstanding balance of approximately $12.9 million and was scheduled to mature on November 17, 2016. The extended loan has a total commitment amount of approximately $15.4 million , bears interest at a variable rate equal to LIBOR plus 2.25% per annum and matures on November 17, 2018. Annapolis Junction Building Six is a Class A office property with approximately 119,000 net rentable square feet located in Annapolis, Maryland. On November 28, 2016, the Company entered into a joint venture with the partner at its North Station development to acquire the air rights for the future development of a hotel property at the site. The joint venture partner contributed an air rights parcel and improvements, with a fair value of approximately $7.4 million , for its initial 50% interest in the joint venture. The Company contributed improvements totaling approximately $0.7 million and will contribute cash totaling approximately $6.7 million for its initial 50% interest. On November 28, 2016, the joint venture entered into a 99 -year air rights lease with a third-party hotel developer/operator. In addition, on November 28, 2016, the Company and its partner entered into a joint venture to acquire the air rights for the future development of a residential tower at the site, consisting of an approximately 40 -story residential tower totaling approximately 320,000 rentable square feet comprised of 440 apartment units. The joint venture partner contributed an air rights parcel, with a fair value of approximately $24.2 million , for its initial 50% interest in the joint venture. The Company contributed cash and improvements totaling approximately $17.7 million and will contribute cash totaling approximately $6.5 million for its initial 50% interest. On December 7, 2016, two joint ventures, in which the Company has a 50% interest in each, combined and extended mortgage loans totaling approximately $21.6 million and $15.1 million collateralized by Annapolis Junction Building Seven and Building Eight, respectively. On April 4, 2016, the mortgage loan collateralized by Annapolis Junction Building Seven had been extended from April 4, 2016 to April 4, 2017, with one , one -year extension option, subject to certain conditions, and bore interest at a variable rate equal to LIBOR plus 1.65% per annum. The mortgage loan collateralized by Annapolis Junction Building Eight bore interest at a variable rate equal to LIBOR plus 1.50% per annum and was scheduled to mature on June 23, 2017, with two , one -year extension options, subject to certain conditions. The new mortgage loan has a total commitment amount of approximately $42.0 million , with an initial balance totaling approximately $36.7 million , bears interest at a variable rate equal to LIBOR plus 2.35% per annum and matures on December 7, 2019, with three , one -year extension options, subject to certain conditions. Annapolis Junction Building Seven and Building Eight are Class A office properties with approximately 127,000 and 126,000 net rentable square feet, respectively, located in Annapolis, Maryland. On December 19, 2016, a joint venture in which the Company has a 50% interest obtained construction financing with a total commitment of $250.0 million collateralized by its Dock 72 development project. The construction financing bears interest at a variable rate equal to LIBOR plus 2.25% per annum and matures on December 18, 2020, with two , one -year extension options, subject to certain conditions. As of December 31, 2016, there have been no amounts drawn under the loan. Dock 72 is a Class A office project with approximately 670,000 net rentable square feet located in Brooklyn, New York.

Mortgage Notes Payable

Mortgage Notes Payable	12 Months Ended
	Dec. 31, 2016
Loans Payable [Abstract]
Mortgage Notes Payable	6. Mortgage Notes Payable The Company had outstanding mortgage notes payable totaling approximately $2.1 billion and $3.4 billion as of December 31, 2016 and 2015 , respectively, each collateralized by one or more buildings and related land included in real estate assets. The mortgage notes payable are generally due in monthly installments and mature at various dates through April 10, 2022 . Fixed rate mortgage notes payable totaled approximately $2.1 billion and $3.4 billion at December 31, 2016 and 2015 , respectively, with contractual interest rates ranging from 4.75% to 7.69% per annum at December 31, 2016 and 2015 (with a weighted-average interest rate of 5.59% and 5.69% per annum (excluding the mezzanine notes payable) at December 31, 2016 and 2015 , respectively). There were no variable rate mortgage loans at December 31, 2016 and 2015. As of December 31, 2016 and 2015 , the LIBOR rate was 0.77% and 0.43% , respectively. On April 11, 2016, the Company used available cash to repay the mortgage loan collateralized by its Fountain Square property located in Reston, Virginia totaling approximately $211.3 million . The mortgage loan bore interest at a fixed rate of 5.71% per annum and was scheduled to mature on October 11, 2016. There was no prepayment penalty. On September 1, 2016, the Company used a portion of the net proceeds from Boston Properties Limited Partnership’s August 2016 offering of senior unsecured notes (See Note 8 ) and available cash to repay the mortgage loan collateralized by its 599 Lexington Avenue property located in New York City totaling $750.0 million . The mortgage loan bore interest at a fixed rate of 5.57% per annum ( 5.41% per annum including the impact of financing costs and interest rate hedges) and was scheduled to mature on March 1, 2017. There was no prepayment penalty. The Company recognized a gain from early extinguishment of debt totaling approximately $0.4 million consisting of the acceleration of the remaining balance related to the effective portion of a previous interest rate hedging program included within accumulated other comprehensive loss, offset by the write-off of unamortized deferred financing costs. On September 1, 2016, the Company used a portion of the net proceeds from Boston Properties Limited Partnership’s August 2016 offering of senior unsecured notes (See Note 8 ) and available cash to repay the mortgage loan collateralized by its Embarcadero Center Four property located in San Francisco, California totaling approximately $344.8 million . The mortgage loan bore interest at a fixed rate of 6.10% per annum ( 7.02% per annum including the impact of financing costs and interest rate hedges) and was scheduled to mature on December 1, 2016. There was no prepayment penalty. The Company recognized a loss from early extinguishment of debt totaling approximately $0.7 million consisting of the write-off of unamortized deferred financing costs and the acceleration of the remaining balance related to the effective portion of a previous interest rate hedging program included within accumulated other comprehensive loss. One mortgage loan totaling approximately $1.3 billion at December 31, 2016 and two mortgage loans totaling approximately $1.5 billion at December 31, 2015 have been accounted for at their fair values on the dates the mortgage loans were assumed in connection with the acquisition or consolidation of real estate. The impact of recording the mortgage loans at fair value resulted in a decrease to interest expense of approximately $46.4 million , $55.0 million and $52.5 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. The cumulative liability related to the fair value adjustments was $33.8 million and $80.2 million at December 31, 2016 and 2015 , respectively, and is included in mortgage notes payable, net in the Consolidated Balance Sheets. Contractual aggregate principal payments of mortgage notes payable at December 31, 2016 are as follows: Principal Payments (in thousands) 2017 $ 1,317,654 2018 18,633 2019 19,670 2020 20,766 2021 40,182 Thereafter 614,710 Total aggregate principal payments 2,031,615 Unamortized balance of historical fair value adjustment 33,830 Deferred financing costs, net (2,358 ) Total carrying value of mortgage notes payable, net $ 2,063,087 The mortgage debt maturities through the end of 2017 include the indebtedness of the consolidated entity in which the Company has a 60% interest and which is collateralized by 767 Fifth Avenue (the General Motors Building) in New York City totaling $1.3 billion . In addition, the consolidated entity has outstanding mezzanine indebtedness totaling $306.0 million . These loans have a weighted-average fixed interest rate of approximately 5.96% per annum and mature in October 2017 and may be prepaid without penalty beginning in June 2017. The Company anticipates approaching the debt markets for the refinancing in the first half of 2017. Based on management’s historical experience in the mortgage debt market, the building’s current cash flow is sufficient to support a refinancing of the current outstanding indebtedness while maintaining a reasonable loan-to-value ratio, although there can be no assurance that the refinancing will occur on the terms currently contemplated or at all.

Derivative and Hedging Instrume

Derivative and Hedging Instruments (Notes)	12 Months Ended
	Dec. 31, 2016
Derivatives and Hedging Activities [Abstract]
Derivative Instruments and Hedging Activities Disclosure [Text Block]	7. Derivative Instruments and Hedging Activities On February 19, 2015, Boston Properties Limited Partnership commenced a planned interest rate hedging program. During the year ended December 31, 2015, Boston Properties Limited Partnership entered into 17 forward-starting interest rate swap contracts that fix the 10 -year swap rate at a weighted-average rate of approximately 2.423% per annum on notional amounts aggregating $550.0 million . These interest rate swap contracts were entered into in advance of a financing with a target commencement date in September 2016 and maturity in September 2026. On August 17, 2016, in conjunction with Boston Properties Limited Partnership’s offering of its 2.750% senior unsecured notes due 2026 (See Note 8 ), the Company terminated the forward-starting interest rate swap contracts and cash-settled the contracts by making cash payments to the counterparties aggregating approximately $49.3 million . The Company recognized approximately $0.1 million of losses on interest rate contracts during the year ended December 31, 2016 related to the partial ineffectiveness of the interest rate contracts. The Company will reclassify into earnings, as an increase to interest expense, approximately $49.2 million (or approximately $4.9 million per year over the 10-year term of the 2.750% senior unsecured notes due 2026) of the amounts recorded in the consolidated balance sheets within accumulated other comprehensive loss, which represents the effective portion of the applicable interest rate contracts. 767 Fifth Partners LLC, which is a subsidiary of the consolidated entity (in which the Company has a 60% interest and owns 767 Fifth Avenue (the General Motors Building) in New York City), entered into 16 forward-starting interest rate swap contracts (including two contracts entered into during the year ended December 31, 2016 with notional amounts aggregating $50.0 million ), that fix the 10 -year swap rate at a weighted-average rate of approximately 2.619% per annum on notional amounts aggregating $450.0 million . These interest rate swap contracts were entered into in advance of a financing with a target commencement date in June 2017 and maturity in June 2027. 767 Fifth Avenue Partners LLC’s interest rate swap contracts consisted of the following at December 31, 2016 (dollars in thousands): Derivative Instrument Aggregate Notional Amount Effective Date Maturity Date Strike Rate Range Balance Sheet Location Fair Value Low High 767 Fifth Partners LLC: Interest Rate Swaps $ 350,000 June 7, 2017 June 7, 2027 2.418 % - 2.950 % Other Liabilities $ (8,773 ) Interest Rate Swaps 100,000 June 7, 2017 June 7, 2027 2.336 % - 2.388 % Prepaid Expenses and Other Assets 509 $ 450,000 $ (8,264 ) Boston Properties Limited Partnership’s and 767 Fifth Avenue Partners LLC’s interest rate swap contracts consisted of the following at December 31, 2015 (dollars in thousands): Derivative Instrument Aggregate Notional Amount Effective Date Maturity Date Strike Rate Range Balance Sheet Location Fair Value Low High Boston Properties Limited Partnership: Interest Rate Swaps $ 400,000 September 1, 2016 September 1, 2026 2.348 % - 2.571 % Other Liabilities $ (5,419 ) Interest Rate Swaps 150,000 September 1, 2016 September 1, 2026 2.129 % - 2.325 % Prepaid Expenses and Other Assets 1,188 $ 550,000 $ (4,231 ) 767 Fifth Partners LLC: Interest Rate Swaps $ 250,000 June 7, 2017 June 7, 2027 2.677 % - 2.950 % Other Liabilities $ (7,247 ) Interest Rate Swaps 150,000 June 7, 2017 June 7, 2027 2.336 % - 2.430 % Prepaid Expenses and Other Assets 1,176 $ 400,000 $ (6,071 ) $ 950,000 $ (10,302 ) Boston Properties Limited Partnership entered into the interest rate swap contracts designated and qualifying as cash flow hedges to reduce its exposure to the variability in future cash flows attributable to changes in the 10 -year swap rate in contemplation of obtaining 10 -year fixed-rate financing in September 2016. The Company’s 767 Fifth Partners LLC consolidated entity entered into the interest rate swap contracts designated and qualifying as cash flow hedges to reduce its exposure to the variability in future cash flows attributable to changes in the 10 -year swap rate in contemplation of obtaining 10 -year fixed-rate financing in June 2017. Boston Properties Limited Partnership has formally documented all of its relationships between hedging instruments and hedged items, as well as its risk-management objective and strategy for undertaking various hedge transactions. Boston Properties Limited Partnership also assesses and documents, both at the hedging instrument’s inception and on an ongoing basis, whether the derivatives that are used in hedging transactions are highly effective in offsetting changes in cash flows associated with the hedged items. All components of the forward-starting interest rate swap contracts were included in the assessment of hedge effectiveness. 767 Fifth Partners LLC has agreements with each of its derivative counterparties that contain a provision where it could be declared in default on its derivative obligations if repayment of its indebtedness is accelerated by the lender due to its default on the indebtedness. As of December 31, 2016 , the fair value of 767 Fifth Partners LLC’s derivatives is in a net liability position, excluding any adjustment for nonperformance risk and excluding accrued interest, related to these agreements of approximately $8.7 million . As of December 31, 2016 , 767 Fifth Partners LLC has not posted any collateral related to these agreements. If 767 Fifth Partners LLC had breached any of these provisions at December 31, 2016 , it could have been required to settle its obligations under the agreements at their termination value of approximately $8.7 million . The Company accounts for the effective portion of changes in the fair value of a derivative in accumulated other comprehensive loss and subsequently reclassifies the effective portion to earnings over the term that the hedged transaction affects earnings. The Company accounts for the ineffective portion of changes in the fair value of a derivative directly in earnings. The Company classifies cash flows related to derivative instruments within its Consolidated Statements of Cash Flows consistent with the nature of the hedged item. 767 Fifth Partners LLC has recorded the changes in fair value of the swap contracts related to the effective portion of the interest rate contracts aggregating approximately $8.8 million in Other Liabilities and approximately $0.5 million in Prepaid Expenses and Other Assets and Accumulated Other Comprehensive Loss within the Company’s Consolidated Balance Sheets. During the year ended December 31, 2016 , 767 Fifth Partners LLC did not record any hedge ineffectiveness. 767 Fifth Partners LLC expects that within the next twelve months it will reclassify into earnings as an increase to interest expense approximately $0.5 million of the amounts recorded within Accumulated Other Comprehensive Loss relating to the forward-starting interest rate swap contracts in effect and as of December 31, 2016 . The following table presents the location in the financial statements of the losses recognized related to the Company’s cash flow hedges for the years ended December 31, 2016 , 2015 and 2014 : Year ended December 31, 2016 2015 2014 (in thousands) Amount of loss related to the effective portion recognized in other comprehensive loss $ (47,144 ) $ (10,302 ) $ — Amount of loss related to the portion subsequently reclassified to earnings $ (3,751 ) (1) $ (2,510 ) $ (2,508 ) Amount of loss related to the ineffective portion and amount excluded from effectiveness testing $ (140 ) $ — $ — ___________ (1) During the year ended December 31, 2016, the Company accelerated the reclassification of amounts in other comprehensive loss to earnings as a result of the hedged forecasted transactions becoming probable not to occur. The accelerated amounts were a loss of approximately $0.2 million and are included in the table above. Boston Properties, Inc. The following table reflects the changes in accumulated other comprehensive loss for the years ended December 31, 2016 , 2015 and 2014 (in thousands): Balance at December 31, 2013 $ (11,556 ) Amortization of interest rate contracts 2,508 Other comprehensive income attributable to noncontrolling interests (256 ) Balance at December 31, 2014 (9,304 ) Effective portion of interest rate contracts (10,302 ) Amortization of interest rate contracts 2,510 Other comprehensive loss attributable to noncontrolling interests 2,982 Balance at December 31, 2015 (14,114 ) Effective portion of interest rate contracts (47,144 ) Amortization of interest rate contracts 3,751 Other comprehensive loss attributable to noncontrolling interests 5,256 Balance at December 31, 2016 $ (52,251 ) Boston Properties Limited Partnership The following table reflects the changes in accumulated other comprehensive loss for the years ended December 31, 2016 , 2015 and 2014 (in thousands): Balance at December 31, 2013 $ (15,481 ) Amortization of interest rate contracts 2,508 Balance at December 31, 2014 (12,973 ) Effective portion of interest rate contracts (10,302 ) Amortization of interest rate contracts 2,510 Other comprehensive loss attributable to noncontrolling interests in property partnership 2,428 Balance at December 31, 2015 (18,337 ) Effective portion of interest rate contracts (47,144 ) Amortization of interest rate contracts 3,751 Other comprehensive loss attributable to noncontrolling interests in property partnership 877 Balance at December 31, 2016 $ (60,853 )

Unsecured Senior Notes

Unsecured Senior Notes	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Unsecured Senior Notes	8. Unsecured Senior Notes The following summarizes the unsecured senior notes outstanding as of December 31, 2016 (dollars in thousands): Coupon/ Stated Rate Effective Rate(1) Principal Amount Maturity Date(2) 10 Year Unsecured Senior Notes 5.875 % 5.967 % $ 700,000 October 15, 2019 10 Year Unsecured Senior Notes 5.625 % 5.708 % 700,000 November 15, 2020 10 Year Unsecured Senior Notes 4.125 % 4.289 % 850,000 May 15, 2021 7 Year Unsecured Senior Notes 3.700 % 3.853 % 850,000 November 15, 2018 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 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 Total principal 7,300,000 Net unamortized discount (18,783 ) Deferred financing costs, net (35,264 ) Total $ 7,245,953 _______________ (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. 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 December 31, 2016 , Boston Properties Limited Partnership was in compliance with each of these financial restrictions and requirements. On January 20, 2016, Boston Properties Limited Partnership completed a public offering of $1.0 billion in aggregate principal amount of its 3.650% unsecured senior notes due 2026. The notes were priced at 99.708% of the principal amount to yield an effective rate (including financing fees) of approximately 3.766% per annum to maturity. The notes will mature on February 1, 2026, unless earlier redeemed. The aggregate net proceeds from the offering were approximately $988.9 million after deducting underwriting discounts and transaction expenses. On August 17, 2016, Boston Properties Limited Partnership completed a public offering of $1.0 billion in aggregate principal amount of its 2.750% unsecured senior notes due 2026. The notes were priced at 99.271% of the principal amount to yield an effective rate, including financing fees and the impact of the settlement of certain forward-starting interest rate swap contracts (See Note 7 ), of approximately 3.495% per annum to maturity. The notes will mature on October 1, 2026, unless earlier redeemed. The aggregate net proceeds from the offering were approximately $984.7 million after deducting underwriting discounts and transaction expenses.

Unsecured Line of Credit

Unsecured Line of Credit	12 Months Ended
	Dec. 31, 2016
Unsecured Line of Credit [Abstract]
Unsecured Line of Credit [Text Block]	9. Unsecured Line of Credit Boston Properties Limited Partnership has a $1.0 billion revolving credit facility (the “Unsecured Line of Credit”) with a maturity date of July 26, 2018 . Boston Properties Limited Partnership may increase the total commitment to $1.5 billion , subject to syndication of the increase and other conditions. At Boston Properties Limited Partnership’s option, loans outstanding under the Unsecured Line of Credit will bear interest at a rate per annum equal to (1), in the case of loans denominated in Dollars, Euro or Sterling, LIBOR or, in the case of loans denominated in Canadian Dollars, CDOR, in each case, plus a margin ranging from 0.925% to 1.70% based on Boston Properties Limited Partnership’s credit rating or (2) an alternate base rate equal to the greatest of (a) the Administrative Agent’s prime rate, (b) the Federal Funds rate plus 0.5% or (c) LIBOR for a one month period plus 1.00% , in each case, plus a margin ranging from 0.0% to 0.70% based on Boston Properties Limited Partnership’s credit rating. The Unsecured Line of Credit also contains a competitive bid option that allows banks that are part of the lender consortium to bid to make loan advances to Boston Properties Limited Partnership at a reduced interest rate. In addition, Boston Properties Limited Partnership is also obligated to pay (1) in quarterly installments a facility fee on the total commitment at a rate per annum ranging from 0.125% to 0.35% based on Boston Properties Limited Partnership’s credit rating and (2) an annual fee on the undrawn amount of each letter of credit equal to the LIBOR margin. Based on Boston Properties Limited Partnership’s current credit rating, the LIBOR and CDOR margin is 1.00% , the alternate base rate margin is 0.0% and the facility fee is 0.15% . At December 31, 2016 and 2015 , there were no amounts outstanding on the Unsecured Line of Credit. The terms of the Unsecured Line of Credit require that Boston Properties Limited Partnership maintain a number of customary financial and other covenants on an ongoing basis, including: (1) a leverage ratio not to exceed 60% , however, the leverage ratio may increase to no greater than 65% provided that it is reduced back to 60% within one year, (2) a secured debt leverage ratio not to exceed 55% , (3) a fixed charge coverage ratio of at least 1.40 , (4) an unsecured debt leverage ratio not to exceed 60% , however, the unsecured debt leverage ratio may increase to no greater than 65% provided that it is reduced back to 60% within one year, (5) an unsecured debt interest coverage ratio of at least 1.75 and (6) limitations on permitted investments. At December 31, 2016 , Boston Properties Limited Partnership was in compliance with each of these financial and other covenant requirements.

Commitments And Contingencies

Commitments And Contingencies	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	10. 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 $12.3 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. Under certain of the Company’s joint venture agreements, if certain return thresholds are achieved the partners will be entitled to an additional promoted interest or payments. In connection with the assumption 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 joint venture entity’s obligation to fund various escrows, including tenant improvements, taxes and insurance in lieu of cash deposits. As of December 31, 2016 , the maximum funding obligation under the guarantee was approximately $41.7 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. In connection with 767 Fifth Partners LLC entering into interest rate swap contracts (See Note 7 ), the Company guaranteed 767 Fifth Partners LLC’s obligations under the hedging agreements in favor of each hedge counterparty. 767 Fifth Partners LLC is the entity that owns 767 Fifth Avenue (the General Motors Building). It is a subsidiary of 767 Venture, LLC, a consolidated entity in which the Company has a 60% interest. 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. From time to time, the Company (or the applicable joint venture) has also agreed to guarantee portions of the principal, interest or other amounts in connection with other unconsolidated joint venture borrowings. In addition to the financial guarantees referenced above, the Company has agreed to customary construction completion guarantees for construction loans, environmental indemnifications and nonrecourse carve-outs (e.g., guarantees against fraud, misrepresentation and bankruptcy) on certain of its unconsolidated joint venture loans. 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 . On September 18, 2014, the Company received an initial distribution totaling approximately $7.7 million , which is included in Base Rent in the Consolidated Statements of Operations for the year ended December 31, 2014. On March 11, 2015, the Company received a second interim distribution totaling approximately $4.5 million , which is included in Base Rent in the Consolidated Statements of Operations for the year ended December 31, 2015. On September 9, 2015, the Company received a third interim distribution totaling approximately $3.6 million , which is also included in Base Rent in the Consolidated Statements of Operations for the year ended December 31, 2015. On July 5, 2016, the Company received a fourth interim distribution totaling approximately $1.4 million , which is included in Base Rent in the Consolidated Statements of Operations for the year ended December 31, 2016, leaving a remaining claim of approximately $28.0 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 December 31, 2016. Concentrations of Credit Risk Management of the Company performs ongoing credit evaluations of tenants and may require tenants to provide some form of credit support such as corporate guarantees and/or other financial guarantees. Although the Company’s properties are geographically diverse and the tenants operate in a variety of industries, to the extent the Company has a significant concentration of rental revenue from any single tenant, the inability of that tenant to make its lease payments could have an adverse effect on the Company. Some potential losses are not covered by insurance. The Company carries insurance coverage on its properties, including those under development, of types and in amounts and with deductibles that it believes are in line with coverage customarily obtained by owners of similar properties. Certain properties owned in joint ventures with third parties are insured by the third party partner with insurance coverage of types and in amounts and with deductibles the Company believes are in line with coverage customarily obtained by owners of similar properties. In response to the uncertainty in the insurance market following the terrorist attacks of September 11, 2001, the Federal Terrorism Risk Insurance Act (as amended, “TRIA”) was enacted in November 2002 to require regulated insurers to make available coverage for “certified” acts of terrorism (as defined by the statute). The expiration date of TRIA was extended to December 31, 2014 by the Terrorism Risk Insurance Program Reauthorization Act of 2007 and further extended to December 31, 2020 by the Terrorism Risk Insurance Program Reauthorization Act of 2015 (“TRIPRA”), and the Company can provide no assurance that it will be extended further. Currently, 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 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 2016, the program trigger was $120 million and the coinsurance was 16% , however, both will increase in subsequent years pursuant to TRIPRA. 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 TRIPRA. The Company may elect to terminate the NBCR Coverage if the Federal Government seeks recoupment for losses paid under TRIA, 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 and maintain terrorism insurance in amounts and on terms that are commercially reasonable. The Company also currently carries earthquake insurance on its properties located in areas known to be subject to earthquakes in an amount and subject to self-insurance that the Company believes is commercially reasonable. 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 (excluding Salesforce Tower) with a $170 million per occurrence limit and a $170 million annual aggregate limit, $20 million of which is provided by IXP, as a direct insurer. The builders risk policy maintained for the development of Salesforce Tower in San Francisco includes a $60 million per occurrence and annual aggregate limit of earthquake coverage. 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. Legal Matters The Company is subject to various legal proceedings and claims that arise in the ordinary course of business. These matters are generally covered by insurance. Management believes that the final outcome of such matters will not have a material adverse effect on the financial position, results of operations or liquidity of the Company. State and Local Tax Matters Because Boston Properties, Inc. is organized and qualifies as a REIT, it is generally not subject to federal income taxes, but is subject to certain state and local taxes. In the normal course of business, certain entities through which the Company owns real estate either have undergone, or are currently undergoing, tax audits. Although the Company believes that it has substantial arguments in favor of its positions in the ongoing audits, in some instances there is no controlling precedent or interpretive guidance on the specific point at issue. Collectively, tax deficiency notices received to date from the jurisdictions conducting the ongoing audits have not been material. However, there can be no assurance that future audits will not occur with increased frequency or that the ultimate result of such audits will not have a material adverse effect on the Company’s results of operations. Environmental Matters It is the Company’s policy to retain independent environmental consultants to conduct or update Phase I environmental assessments (which generally do not involve invasive techniques such as soil or ground water sampling) and asbestos surveys in connection with the Company’s acquisition of properties. These pre-purchase environmental assessments have not revealed environmental conditions that the Company believes will have a material adverse effect on its business, assets, financial condition, results of operations or liquidity, and the Company is not otherwise aware of environmental conditions with respect to its properties that the Company believes would have such a material adverse effect. However, from time to time environmental conditions at the Company’s properties have required and may in the future require environmental testing and/or regulatory filings, as well as remedial action. In February 1999, the Company (through a joint venture) acquired from Exxon Corporation a property in Massachusetts that was formerly used as a petroleum bulk storage and distribution facility and was known by the state regulatory authority to contain soil and groundwater contamination. The Company developed an office park on the property. The Company engaged a specially licensed environmental consultant to oversee the management of contaminated soil and groundwater that was disturbed in the course of construction. Under the property acquisition agreement, Exxon agreed to (1) bear the liability arising from releases or discharges of oil and hazardous substances which occurred at the site prior to the Company’s ownership, (2) continue monitoring and/or remediating such releases and discharges as necessary and appropriate to comply with applicable requirements, and (3) indemnify the Company for certain losses arising from preexisting site conditions. Any indemnity claim may be subject to various defenses, and there can be no assurance that the amounts paid under the indemnity, if any, would be sufficient to cover the liabilities arising from any such releases and discharges. Environmental investigations at some of the Company’s properties and certain properties owned by affiliates of the Company have identified groundwater contamination migrating from off-site source properties. In each case the Company engaged a licensed environmental consultant to perform the necessary investigations and assessments and to prepare any required submittals to the regulatory authorities. In each case the environmental consultant concluded that the properties qualify under the regulatory program or the regulatory practice for a status which eliminates certain deadlines for conducting response actions at a site. The Company also believes that these properties qualify for liability relief under certain statutory provisions or regulatory practices regarding upgradient releases. Although the Company believes that the current or former owners of the upgradient source properties may bear responsibility for some or all of the costs of addressing the identified groundwater contamination, the Company will take such further response actions (if any) that it deems necessary or advisable. Other than periodic testing at some of these properties, no such additional response actions are anticipated at this time. Some of the Company’s properties and certain properties owned by the Company’s affiliates are located in urban, industrial and other previously developed areas where fill or current or historical uses of the areas have caused site contamination. Accordingly, it is sometimes necessary to institute special soil and/or groundwater handling procedures and/or include particular building design features in connection with development, construction and other property operations in order to achieve regulatory closure and/or ensure that contaminated materials are addressed in an appropriate manner. In these situations, it is the Company’s practice to investigate the nature and extent of detected contamination, including potential issues associated with contaminant migration, assess potential liability risks and estimate the costs of required response actions and special handling procedures. The Company then uses this information as part of its decision-making process with respect to the acquisition, deal structure and/or development of the property. For example, the Company owns a parcel in Massachusetts which was formerly used as a quarry/asphalt batching facility. Pre-purchase testing indicated that the site contained relatively low levels of certain contaminants. The Company has developed an office park on this property. Prior to and during redevelopment activities, the Company engaged a specially licensed environmental consultant to monitor environmental conditions at the site and prepare necessary regulatory submittals based on the results of an environmental risk characterization. A submittal has been made to the regulatory authorities in order to achieve regulatory closure at this site. The submittal included an environmental deed restriction that mandates compliance with certain protective measures in a portion of the site where low levels of residual soil contamination have been left in place in accordance with applicable laws. The Company expects that resolution of the environmental matters relating to the above will not have a material impact on its business, assets, financial condition, results of operations or liquidity. However, the Company cannot assure you that it has identified all environmental liabilities at its properties, that all necessary remediation actions have been or will be undertaken at the Company’s properties or that the Company will be indemnified, in full or at all, in the event that such environmental liabilities arise. Tax Protection Obligations In connection with the acquisition of 767 Fifth Avenue (the General Motors Building), Boston Properties Limited Partnership entered into an agreement for the benefit of the contributing party which specifically states that Boston Properties Limited Partnership will not sell or otherwise transfer the property in a taxable transaction until June 9, 2017. If Boston Properties Limited Partnership does sell or transfer the property in a taxable transaction, it would be liable to the contributor for contractual damages.

Noncontrolling Interests

Noncontrolling Interests	12 Months Ended
	Dec. 31, 2016
Noncontrolling Interest [Abstract]
Noncontrolling Interests	11. 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 December 31, 2016 , the noncontrolling interests in Boston Properties Limited Partnership consisted of 17,079,511 OP Units, 904,588 LTIP Units (including 166,629 2012 OPP Units and 93,928 2013 MYLTIP Units), 474,415 2014 MYLTIP Units, 367,218 2015 MYLTIP Units and 473,360 2016 MYLTIP Units held by parties other than Boston Properties, Inc. Noncontrolling Interest—Redeemable Preferred Units On March 11, 2014, Boston Properties Limited Partnership notified the holders of the outstanding Series Two Preferred Units that it had elected to redeem all of such Series Two Preferred Units on May 12, 2014. As a result of Boston Properties Limited Partnership's election to redeem the units, as of May 12, 2014, the holders of all remaining 666,116 Series Two Preferred Units converted such units into an aggregate of 874,168 OP Units. The Series Two Preferred Units bore a preferred distribution equal to the greater of (1) the distribution which would have been paid in respect of the Series Two Preferred Unit had such Series Two Preferred Unit been converted into an OP Unit (including both regular and special distributions) or (2) 6.00% per annum on a liquidation preference of $50.00 per unit, and were convertible into OP Units at a rate of $38.10 per Preferred Unit ( 1.312336 OP Units for each Preferred Unit). Due to the holders’ redemption option existing outside the control of the Company, the Series Two Preferred Units were presented outside of permanent equity in the Company’s Consolidated Balance Sheets. On June 25, 2015, Boston Properties Limited Partnership redeemed the remaining 12,667 Series Four Preferred Units for cash totaling approximately $0.6 million , plus accrued and unpaid distributions. The Series Four Preferred Units bore a preferred distribution equal to 2.00% per annum on a liquidation preference of $50.00 per unit and were not convertible into OP Units. The holders of Series Four Preferred Units had the right, at certain times and subject to certain conditions set forth in the Certificate of Designations establishing the rights, limitations and preferences of the Series Four Preferred Units, to require Boston Properties Limited Partnership to redeem all of their units for cash at the redemption price of $50.00 per unit. Boston Properties Limited Partnership also had the right, at certain times and subject to certain conditions, to redeem all of the Series Four Preferred Units for cash at the redemption price of $50.00 per unit. In order to secure the performance of certain post-issuance obligations by the holders, all of such outstanding Series Four Preferred Units were subject to forfeiture pursuant to the terms of a pledge agreement and not eligible for redemption until the security interest was released and unless such security interest is released. On May 19, 2014, Boston Properties Limited Partnership released to the holders 319,687 Series Four Preferred Units that were previously subject to the security interest. On July 3, 2014, Boston Properties Limited Partnership redeemed such units for cash totaling approximately $16.0 million . On October 16, 2014, Boston Properties Limited Partnership released to the holders 27,773 Series Four Preferred Units that were previously subject to the security interest under the pledge agreement. On November 5, 2014, Boston Properties Limited Partnership redeemed such units for cash totaling approximately $1.4 million . Due to the holders’ redemption option existing outside the control of the Company, the Series Four Preferred Units were presented outside of permanent equity in the Company’s Consolidated Balance Sheets. Boston Properties, Inc. The following table reflects the activity of the noncontrolling interests—redeemable preferred units of Boston Properties, Inc. for the years ended December 31, 2015 and 2014 (in thousands): Balance at December 31, 2013 $ 51,312 Net income 1,023 Distributions (1,023 ) Redemption of redeemable preferred units (Series Four Preferred Units) (17,373 ) Conversion of redeemable preferred units (Series Two Preferred Units) to common units (33,306 ) Balance at December 31, 2014 633 Net income 6 Distributions (6 ) Redemption of redeemable preferred units (Series Four Preferred Units) (633 ) Balance at December 31, 2015 $ — Boston Properties Limited Partnership The following table reflects the activity of the noncontrolling interests—redeemable preferred units of Boston Properties Limited Partnership for the years ended December 31, 2015 and 2014 (in thousands): Balance at December 31, 2013 $ 105,746 Net income 1,023 Distributions (1,023 ) Redemption of redeemable preferred units (Series Four Preferred Units) (17,373 ) Reallocation of partnership interest (1) (87,740 ) Balance at December 31, 2014 633 Net income 6 Distributions (6 ) Redemption of redeemable preferred units (Series Four Preferred Units) (633 ) Balance at December 31, 2015 $ — _____________ (1) Includes the conversion of 666,116 Series Two Preferred Units into 874,168 OP Units during the year ended December 31, 2014 . Noncontrolling Interest—Redeemable Interest in Property Partnership On October 4, 2012, the Company completed the formation of a joint venture, that owns and operates Fountain Square located in Reston, Virginia. The joint venture partner contributed the property valued at approximately $385.0 million and related mortgage indebtedness totaling approximately $211.3 million for a 50% interest in the joint venture. The Company contributed cash totaling approximately $87.0 million for its 50% interest, which cash was distributed to the joint venture partner. Pursuant to the joint venture agreement (i) the Company had rights to acquire the partner’s 50% interest and (ii) the partner had the right to cause the Company to acquire the partner’s interest on January 4, 2016, in each case at a fixed price totaling approximately $102.0 million in cash. The fixed price option rights were to expire on January 31, 2016. The Company was consolidating this joint venture due to the Company’s right to acquire the partner’s 50% interest. The Company recorded the noncontrolling interest at its acquisition-date fair value as temporary equity, due to the redemption option existing outside the control of the Company. The Company was accreting the changes in the redemption value quarterly over the period from the acquisition date to the earliest redemption date using the effective interest method. The Company was recording the accretion after the allocation of net income and distributions of cash flow to the noncontrolling interest account balance. On August 6, 2015, the parties amended the joint venture agreement to require the Company to acquire its partner’s 50% interest on September 15, 2015 for approximately $100.9 million in cash. On September 15, 2015, the Company acquired its partner’s 50% interest in the consolidated entity that owns Fountain Square for cash of approximately $100.9 million plus working capital and closing prorations and the partner’s share of assumed mortgage indebtedness totaling approximately $105.6 million . The following table reflects the activity of the noncontrolling interest—redeemable interest in property partnership in the Company’s Fountain Square consolidated entity for the years ended December 31, 2015 and 2013 (in thousands): Balance at December 31, 2013 $ 99,609 Net loss (603 ) Distributions (6,000 ) Adjustment to reflect redeemable interest at redemption value 11,686 Balance at December 31, 2014 104,692 Net loss (7 ) Distributions (2,900 ) Adjustment to reflect redeemable interest at redemption value 5,128 Acquisition of interest (106,913 ) Balance at December 31, 2015 $ — Noncontrolling Interest—Common Units During the years ended December 31, 2016 and 2015 , 190,857 and 424,236 OP Units, respectively, were presented by the holders for redemption (including 103,847 and 65,192 OP Units, respectively, issued upon conversion of LTIP Units, 2012 OPP Units and 2013 MYLTIP Units) and were redeemed by Boston Properties, Inc. in exchange for an equal number of shares of Common Stock. Boston Properties Limited Partnership exercised its right under the terms of its partnership agreement to convert an aggregate of 625,043 eligible LTIP Units (including an aggregate of 32,349 2012 OPP Units and 2013 MYLTIP Units) into Common Units effective as of May 2, 2016. These conversions were effected solely for administrative efficiency and had no substantive impact on the rights of Boston Properties Limited Partnership or the holders of these LTIP Units, as the economic and other rights of the LTIP Units converted were substantively identical to those of the Common Units. In the future, Boston Properties Limited Partnership intends to convert LTIP Units (including 2012 OPP Units and MYLTIP Units) into Common Units promptly after they become eligible for conversion. The May 2016 conversions were, and future conversions will be, effected at the election of Boston Properties Limited Partnership and are without regard to the investment intentions of the holders of the units. At December 31, 2016 , Boston Properties Limited Partnership had outstanding 474,415 2014 MYLTIP Units, 367,218 2015 MYLTIP Units and 473,360 2016 MYLTIP Units (See Note 17 ). Prior to the applicable measurement date (February 3, 2017 for 2014 MYLTIP Units (See Note 20), February 4, 2018 for 2015 MYLTIP Units and February 9, 2019 for 2016 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 January 31, 2014, the measurement period for the Company’s 2011 OPP Unit awards expired and Boston Properties, Inc.’s TSR was not sufficient for employees to earn and therefore become eligible to vest in any of the 2011 OPP Unit awards. As a result, the Company accelerated the then remaining unrecognized compensation expense totaling approximately $1.2 million during the year ended December 31, 2014. Accordingly, all 2011 OPP Unit awards were automatically forfeited. On February 6, 2015, the measurement period for the Company’s 2012 OPP Unit awards ended and Boston Properties, Inc.’s TSR performance was sufficient for employees to earn and therefore become eligible to vest in a portion of the 2012 OPP Unit awards. The final outperformance pool was determined to be approximately $32.1 million , or approximately 80% of the total maximum outperformance pool of $40.0 million . As a result, 174,549 2012 OPP Units were automatically forfeited. On February 4, 2016, the measurement period for the Company’s 2013 MYLTIP awards ended and, based on Boston Properties, Inc.’s relative TSR performance, the final awards were determined to be 109.5% of target, or an aggregate of approximately $13.5 million . As a result, 205,762 2013 MYLTIP Units 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 and, after the February 4, 2016 measurement date, the 2013 MYLTIP Units) and its distributions on the 2013 MYLTIP Units (prior to the February 4, 2016 measurement date), 2014 MYLTIP Units, 2015 MYLTIP Units and 2016 MYLTIP Units (after the February 10, 2016 issuance date) paid in 2016: Record Date Payment Date Distributions per OP Unit and LTIP Unit Distributions per MYLTIP Unit December 30, 2016 January 30, 2017 $0.75 $0.075 September 30, 2016 October 31, 2016 $0.65 $0.065 June 30, 2016 July 29, 2016 $0.65 $0.065 March 31, 2016 April 29, 2016 $0.65 $0.065 December 31, 2015 January 28, 2016 $1.90 (1) $0.065 _______________ (1) Includes a special distribution of $1.25 per unit. 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 and 2013 MYLTIP Units) assuming that all conditions had been met for the conversion thereof) had all of such units been redeemed at December 31, 2016 was approximately $2.3 billion based on the last reported price of a share of Common Stock on the New York Stock Exchange of $125.78 per share on December 31, 2016 . Boston Properties Limited Partnership The following table reflects the activity of noncontrolling interests—redeemable common units of Boston Properties Limited Partnership for the years ended December 31, 2016 , 2015 and 2014 (in thousands): Balance at December 31, 2013 $ 1,710,218 Contributions 23,990 Net income 50,862 Distributions (126,948 ) Conversion of redeemable partnership units (2,700 ) Unearned compensation (2,813 ) Other comprehensive income 256 Adjustment to reflect redeemable partnership units at redemption value 657,181 Balance at December 31, 2014 2,310,046 Contributions 39,030 Net income 66,951 Distributions (69,447 ) Conversion of redeemable partnership units (14,343 ) Unearned compensation (4,579 ) Other comprehensive loss (554 ) Adjustment to reflect redeemable partnership units at redemption value (40,415 ) Balance at December 31, 2015 2,286,689 Contributions 31,395 Net income 59,260 Distributions (49,087 ) Conversion of redeemable partnership units (6,461 ) Unearned compensation (3,464 ) Other comprehensive loss (4,379 ) Adjustment to reflect redeemable partnership units at redemption value (51,913 ) Balance at December 31, 2016 $ 2,262,040 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 $1.5 billion at December 31, 2016 and approximately $1.6 billion at December 31, 2015 , are included in Noncontrolling Interests—Property Partnerships on the accompanying Consolidated Balance Sheets. On October 30, 2014, the Company completed the sale of a 45% interest in each of 601 Lexington Avenue in New York City and Atlantic Wharf Office Building and 100 Federal Street in Boston for an aggregate gross sale price of approximately $1.827 billion in cash, less the partner’s pro rata share of the indebtedness collateralized by 601 Lexington Avenue. Net cash proceeds totaled approximately $1.497 billion , after the payment of transaction costs. In connection with the sale, the Company formed a limited liability company for each property with the buyer and will provide customary property management and leasing services to the joint ventures. 601 Lexington Avenue is a 1,669,000 square foot Class A office complex located in Midtown Manhattan. The property consists of a 59 -story tower as well as a six -story low-rise office and retail building. The property is subject to existing mortgage indebtedness of approximately $712.9 million . The Atlantic Wharf Office Building is a 791,000 square foot Class A office tower located on Boston’s Waterfront. 100 Federal Street is a 1,323,000 square foot Class A office tower located in Boston’s Financial District. The transaction did not qualify as a sale of real estate for financial reporting purposes as the Company continues to effectively control these properties and thus will continue to account for the properties on a consolidated basis in its financial statements. The Company has accounted for the transaction as an equity transaction and has recognized noncontrolling interest in its consolidated balance sheets totaling approximately $849.0 million , which is equal to 45% of the aggregate carrying value of the total equity of the properties immediately prior to the transaction. The difference between the net cash proceeds received and the noncontrolling interest recognized, which was approximately $648.5 million , has not been reflected as a gain on sale of real estate in the Company’s consolidated statements of operations and has instead been reflected as an increase in Additional Paid-in Capital in the Company’s Consolidated Balance Sheets. On September 18, 2015, a consolidated entity in which the Company has a 50% interest completed the sale of its 505 9th Street, N.W. property located in Washington, DC for approximately $318.0 million , including the assumption by the buyer of approximately $117.0 million of mortgage indebtedness. 505 9th Street, N.W. is an approximately 322,000 net rentable square foot Class A office building. Net cash proceeds totaled approximately $194.6 million , of which the partners’ share was approximately $97.3 million . The Company recognized a gain on sale of real estate totaling approximately $199.5 million and $199.7 million for Boston Properties, Inc. and Boston Properties Limited Partnership, respectively, of which approximately $101.1 million was allocated to the outside partners and is included within Noncontrolling Interests in Property Partnerships in the Company’s Consolidated Statements of Operations. On December 10, 2015, the consolidated entity was dissolved and the Company reclassified the remaining noncontrolling interest balance totaling approximately $4.1 million to Accounts Payable and Accrued Expenses on the Consolidated Balances Sheets, of which approximately $0.2 million is outstanding at December 31, 2016. 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 venture agreement, if the Company elects 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 has commenced vertical construction of the project, then the partner’s capital funding obligation shall be limited, in which event the Company shall 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 have agreed to structure this funding by the Company as preferred equity rather than a loan. The preferred equity contributed by the Company shall earn a preferred return equal to LIBOR plus 3.00% per annum and shall be payable to the Company out of any distributions to which the partner would otherwise be entitled until such preferred equity and preferred return have been repaid to the Company. As of December 31, 2016 , approximately $4.3 million of preferred equity had been contributed by the Company to the venture. The following table reflects the activity of the noncontrolling interests—property partnerships for the years ended December 31, 2016 , 2015 and 2014 (in thousands): Balance at December 31, 2013 $ 726,132 Capital contributions 887,975 Net income 19,478 Distributions (31,118 ) Balance at December 31, 2014 1,602,467 Capital contributions 3,758 Dissolution (4,082 ) Net income 144,734 Accumulated other comprehensive loss (2,428 ) Distributions (170,049 ) Balance at December 31, 2015 1,574,400 Capital contributions 10,756 Net loss (2,068 ) Accumulated other comprehensive loss (877 ) Distributions (51,564 ) Balance at December 31, 2016 $ 1,530,647

Stockholders' Equity _ Partners

Stockholders' Equity / Partners' Capital	12 Months Ended
	Dec. 31, 2016
Equity [Abstract]
Stockholders' Equity	12. Stockholders’ Equity / Partners’ Capital Boston Properties, Inc. As of December 31, 2016 , Boston Properties, Inc. had 153,790,175 shares of Common Stock outstanding. On June 3, 2014, Boston Properties, Inc. established an “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. 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 since its inception. During the year ended December 31, 2016 , there were no options to purchase Common Stock exercised. During the year ended December 31, 2015, Boston Properties, Inc. issued 11,447 shares of Common Stock upon the exercise of options to purchase Common Stock. During the years ended December 31, 2016 and 2015 , Boston Properties, Inc. issued 190,857 and 424,236 shares of Common Stock, respectively, in connection with the redemption of an equal number of redeemable OP Units from third parties. 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 payable in 2016: Record Date Payment Date Dividend (Per Share) Distribution (Per Unit) December 30, 2016 January 30, 2017 $0.75 $0.75 September 30, 2016 October 31, 2016 0.65 0.65 June 30, 2016 July 29, 2016 0.65 0.65 March 31, 2016 April 29, 2016 0.65 0.65 December 31, 2015 January 28, 2016 1.90 (1) 1.90 (1) _______________ (1) Includes a special dividend/distribution of $1.25 per share/OP Unit and LTIP Unit. Preferred Stock As of December 31, 2016, 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. may not redeem the Series B Preferred Stock prior to March 27, 2018, except in certain circumstances relating to the preservation of Boston Properties, Inc.’s REIT status. On or after March 27, 2018, 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 payable in 2016: Record Date Payment Date Dividend (Per Share) February 3, 2017 February 15, 2017 $32.8125 November 4, 2016 November 15, 2016 32.8125 August 5, 2016 August 15, 2016 32.8125 May 5, 2016 May 16, 2016 32.8125 February 5, 2016 February 16, 2016 32.8125 Boston Properties Limited Partnership The following table presents the changes in the issued and outstanding partners’ capital units since January 1, 2014: General Partner Units Limited Partner Units Total Partners’ Outstanding at December 31, 2013 1,700,222 151,282,879 152,983,101 Units issued to Boston Properties, Inc. related to Common Stock issued under the Employee Stock Purchase Plan 555 6,409 6,964 Units issued to Boston Properties, Inc. related to Common Stock issued under the Stock Option and Incentive Plan, net 3,476 40,158 43,634 Units issued to Boston Properties, Inc. related to Common Stock issued in exchange for OP Units 6,391 73,855 80,246 Outstanding at December 31, 2014 1,710,644 151,403,301 153,113,945 Units issued to Boston Properties, Inc. related to Common Stock issued under the Employee Stock Purchase Plan 59 6,140 6,199 Units issued to Boston Properties, Inc. related to Common Stock issued under the Stock Option and Incentive Plan, net 340 35,246 35,586 Units issued to Boston Properties, Inc. related to Common Stock issued in exchange for OP Units 4,049 420,187 424,236 Outstanding at December 31, 2015 1,715,092 151,864,874 153,579,966 Units issued to Boston Properties, Inc. related to Common Stock issued under the Employee Stock Purchase Plan 72 5,623 5,695 Units issued to Boston Properties, Inc. related to Common Stock issued under the Stock Option and Incentive Plan, net 172 13,485 13,657 Units issued to Boston Properties, Inc. related to Common Stock issued in exchange for OP Units 2,407 188,450 190,857 Outstanding at December 31, 2016 1,717,743 152,072,432 153,790,175 As of December 31, 2016 , Boston Properties, Inc. owned 1,717,743 general partnership units and 152,072,432 limited partnership units. The following table reflects the activity of the Series B Preferred Units for the years ended December 31, 2016 , 2015 and 2014 (in thousands), which activity is included within Boston Properties Limited Partnership’s Consolidated Statements of Partners’ Capital: Balance at December 31, 2013 $ 193,623 Net income 10,500 Distributions (10,500 ) Balance at December 31, 2014 193,623 Net income 10,500 Distributions (10,500 ) Balance at December 31, 2015 193,623 Net income 10,500 Distributions (10,500 ) Balance at December 31, 2016 $ 193,623

Future Minimum Rents

Future Minimum Rents	12 Months Ended
	Dec. 31, 2016
Future Minimum Rents [Abstract]
Future Minimum Rents [Text Block]	13. Future Minimum Rents The properties are leased to tenants under net operating leases with initial term expiration dates ranging from 2017 to 2046 . The future contractual minimum lease payments to be received (excluding operating expense reimbursements) by the Company as of December 31, 2016 , under non-cancelable operating leases which expire on various dates through 2046 , are as follows: Years Ending December 31, (in thousands) 2017 $ 1,906,847 2018 1,903,887 2019 1,887,137 2020 1,741,024 2021 1,553,526 Thereafter 9,367,433 No single tenant represented more than 10.0% of the Company’s total rental revenue for the years ended December 31, 2016 , 2015 and 2014 .

Segment Information

Segment Information	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Segment Reporting Disclosure [Text Block]	14. Segment Information The following tables present reconciliations of Net Income Attributable to Boston Properties, Inc. Common Shareholders to Net Operating Income and Net Income Attributable to Boston Properties Limited Partnership Common Unitholders to Net Operating Income for the years ended December 31, 2016 , 2015 and 2014 . Boston Properties, Inc. Year ended December 31, 2016 2015 2014 (in thousands) Net income attributable to Boston Properties, Inc. common shareholders $ 502,285 $ 572,606 $ 433,111 Add: Preferred dividends 10,500 10,500 10,500 Noncontrolling interest—common units of the Operating Partnership 59,260 66,951 50,862 Noncontrolling interest—redeemable preferred units of the Operating Partnership — 6 1,023 Noncontrolling interest in property partnerships (2,068 ) 149,855 30,561 Losses from interest rate contracts 140 — — Losses from early extinguishments of debt 371 22,040 10,633 Interest expense 412,849 432,196 455,743 Depreciation and amortization expense 694,403 639,542 628,573 Impairment loss 1,783 — — Transaction costs 2,387 1,259 3,140 General and administrative expense 105,229 96,319 98,937 Less: Gains on sales of real estate 80,606 375,895 168,039 Gains (losses) from investments in securities 2,273 (653 ) 1,038 Interest and other income 7,230 6,777 8,765 Gain on sale of investment in unconsolidated joint venture 59,370 — — Income from unconsolidated joint ventures 8,074 22,770 12,769 Development and management services income 28,284 22,554 25,316 Net Operating Income $ 1,601,302 $ 1,563,931 $ 1,507,156 Boston Properties Limited Partnership Year ended December 31, 2016 2015 2014 (in thousands) Net income attributable to Boston Properties Limited Partnership common unitholders $ 575,341 $ 648,748 $ 499,129 Add: Preferred distributions 10,500 10,500 10,500 Noncontrolling interest—redeemable preferred units — 6 1,023 Noncontrolling interest in property partnerships (2,068 ) 149,855 30,561 Losses from interest rate contracts 140 — — Losses from early extinguishments of debt 371 22,040 10,633 Interest expense 412,849 432,196 455,743 Depreciation and amortization expense 682,776 631,549 620,064 Impairment loss 1,783 — — Transaction costs 2,387 1,259 3,140 General and administrative expense 105,229 96,319 98,937 Less: Gains on sales of real estate 82,775 377,093 174,686 Gains (losses) from investments in securities 2,273 (653 ) 1,038 Interest and other income 7,230 6,777 8,765 Gain on sale of investment in unconsolidated joint venture 59,370 — — Income from unconsolidated joint ventures 8,074 22,770 12,769 Development and management services income 28,284 22,554 25,316 Net Operating Income $ 1,601,302 $ 1,563,931 $ 1,507,156 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, the most directly comparable GAAP financial measures, plus (1) preferred dividends/distributions, noncontrolling interests, losses from interest rate contracts, losses from early extinguishments of debt, interest expense, depreciation and amortization, impairment loss, transaction costs and general and administrative expense less (2) gains on sales of real estate, gains (losses) from investments in securities, interest and other income, gain on sale of investment in unconsolidated joint venture, income from unconsolidated joint ventures and development and management services income. The Company believes NOI is useful to investors as a performance measure and believes it provides useful information to investors regarding its financial condition and results of operations 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., for other investment activity). In addition, because of historical cost accounting and useful life estimates, depreciation and amortization 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. 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, noncontrolling interests, losses from interest rate contracts, losses from early extinguishments of debt, interest expense, depreciation and amortization expense, impairment loss, transactions costs, general and administrative expenses, gains on sales of real estate, gains (losses) from investments in securities, interest and other income, gain on sale of investment in unconsolidated joint venture, income from unconsolidated joint ventures and development and management services income are not included in NOI as internal reporting addresses these items on a corporate level. The Company’s segments are based on the Company’s method of internal reporting which classifies its operations by both geographic area and property type. The Company’s segments by geographic area are Boston, New York, San Francisco and Washington, DC. Segments by property type include: Office, Residential and Hotel. Beginning on January 1, 2016, the properties that were historically included in the Company’s Office/Technical segment are now included in the Office segment to align with its method of internal reporting, which shifted after the disposition of 415 Main Street in Cambridge, Massachusetts. As such, the amounts previously included in Office/Technical are now included in Office for all periods presented. Information by geographic area and property type (dollars in thousands): For the year ended December 31, 2016 : Boston New York San Francisco Washington, DC Total Rental Revenue: Office $ 727,265 $ 1,012,518 $ 318,609 $ 402,561 $ 2,460,953 Residential 4,812 — — 11,887 16,699 Hotel 44,884 — — — 44,884 Total 776,961 1,012,518 318,609 414,448 2,522,536 % of Grand Totals 30.80 % 40.14 % 12.63 % 16.43 % 100.00 % Rental Expenses: Office 282,827 363,188 100,787 135,890 882,692 Residential 2,708 — — 4,368 7,076 Hotel 31,466 — — — 31,466 Total 317,001 363,188 100,787 140,258 921,234 % of Grand Totals 34.41 % 39.42 % 10.94 % 15.23 % 100.00 % Net operating income $ 459,960 $ 649,330 $ 217,822 $ 274,190 $ 1,601,302 % of Grand Totals 28.73 % 40.55 % 13.60 % 17.12 % 100.00 % For the year ended December 31, 2015 : Boston New York San Francisco Washington, DC Total Rental Revenue: Office $ 716,246 $ 1,000,030 $ 302,434 $ 384,628 $ 2,403,338 Residential 4,801 — — 14,082 18,883 Hotel 46,046 — — — 46,046 Total 767,093 1,000,030 302,434 398,710 2,468,267 % of Grand Totals 31.08 % 40.52 % 12.25 % 16.15 % 100.00 % Rental Expenses: Office 287,341 346,897 98,206 131,581 864,025 Residential 2,006 — — 6,221 8,227 Hotel 32,084 — — — 32,084 Total 321,431 346,897 98,206 137,802 904,336 % of Grand Totals 35.54 % 38.36 % 10.86 % 15.24 % 100.00 % Net operating income $ 445,662 $ 653,133 $ 204,228 $ 260,908 $ 1,563,931 % of Grand Totals 28.50 % 41.76 % 13.06 % 16.68 % 100.00 % For the year ended December 31, 2014 : Boston New York San Francisco Washington, DC Total Rental Revenue: Office $ 715,917 $ 928,692 $ 261,221 $ 396,274 $ 2,302,104 Residential 4,528 — — 21,665 26,193 Hotel 43,385 — — — 43,385 Total 763,830 928,692 261,221 417,939 2,371,682 % of Grand Totals 32.21 % 39.16 % 11.01 % 17.62 % 100.00 % Rental Expenses: Office 278,120 315,330 90,133 135,785 819,368 Residential 1,957 — — 13,965 15,922 Hotel 29,236 — — — 29,236 Total 309,313 315,330 90,133 149,750 864,526 % of Grand Totals 35.78 % 36.47 % 10.43 % 17.32 % 100.00 % Net operating income $ 454,517 $ 613,362 $ 171,088 $ 268,189 $ 1,507,156 % of Grand Totals 30.16 % 40.70 % 11.35 % 17.79 % 100.00 %

Earnings Per Share _ Common Uni

Earnings Per Share / Common Unit	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Earnings Per Share	15. 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 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. The terms of the Series Two Preferred Units enabled the holders to obtain OP Units of Boston Properties Limited Partnership, and therefore Common Stock of Boston Properties, Inc., and as a result these are considered participating securities. 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., LTIP Units, 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 OPP Units and MYLTIP Units require the Company 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. For the Year Ended December 31, 2016 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 $ 502,285 153,715 $ 3.27 Allocation of undistributed earnings to participating securities (283 ) — — Net income attributable to Boston Properties, Inc. common shareholders $ 502,002 153,715 $ 3.27 Effect of Dilutive Securities: Stock Based Compensation — 262 (0.01 ) Diluted Earnings: Net income attributable to Boston Properties, Inc. common shareholders $ 502,002 153,977 $ 3.26 For the Year Ended December 31, 2015 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 $ 572,606 153,471 $ 3.73 Effect of Dilutive Securities: Stock Based Compensation — 373 (0.01 ) Diluted Earnings: Net income attributable to Boston Properties, Inc. common shareholders $ 572,606 153,844 $ 3.72 For the Year Ended December 31, 2014 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 $ 433,111 153,089 $ 2.83 Effect of Dilutive Securities: Stock Based Compensation — 219 — Diluted Earnings: Net income attributable to Boston Properties, Inc. common shareholders $ 433,111 153,308 $ 2.83 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. The terms of the Series Two Preferred Units enable the holders to obtain OP Units of Boston Properties Limited Partnership and as a result these are considered participating securities. 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, 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 OPP Units and 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 17,646,000 , 17,668,000 and 17,364,000 redeemable common units for the years ended December 31, 2016 , 2015 and 2014 , respectively. For the Year Ended December 31, 2016 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 $ 575,341 171,361 $ 3.36 Allocation of undistributed earnings to participating securities (316 ) — — Net income attributable to Boston Properties Limited Partnership common unitholders $ 575,025 171,361 $ 3.36 Effect of Dilutive Securities: Stock Based Compensation — 262 (0.01 ) Diluted Earnings: Net income attributable to Boston Properties Limited Partnership common unitholders $ 575,025 171,623 $ 3.35 For the Year Ended December 31, 2015 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 $ 648,748 171,139 $ 3.79 Effect of Dilutive Securities: Stock Based Compensation — 373 (0.01 ) Diluted Earnings: Net income attributable to Boston Properties Limited Partnership common unitholders $ 648,748 171,512 $ 3.78 For the Year Ended December 31, 2014 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 $ 499,129 170,453 $ 2.93 Effect of Dilutive Securities: Stock Based Compensation — 219 (0.01 ) Diluted Earnings: Net income attributable to Boston Properties Limited Partnership common unitholders $ 499,129 170,672 $ 2.92

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2016
Employee Benefit Plans [Abstract]
Compensation and Employee Benefit Plans [Text Block]	16. Employee Benefit Plans Effective January 1, 1985, the predecessor of the Company adopted a 401(k) Savings Plan (the “Plan”) for its employees. Under the Plan, as amended, employees, as defined, are eligible to participate in the Plan after they have completed three months of service. Upon formation, the Company adopted the Plan and the terms of the Plan. Under the Plan, as amended, the Company’s matching contribution equals 200% of the first 3% of participant’s eligible earnings contributed (utilizing earnings that are not in excess of an amount established by the IRS ( $265,000 , $265,000 and $260,000 in 2016 , 2015 and 2014 , respectively), indexed for inflation) with no vesting requirement. The Company’s aggregate matching contribution for the years ended December 31, 2016 , 2015 and 2014 was $4.0 million , $3.7 million and $3.5 million , respectively. The Plan also provides for supplemental retirement contributions to certain employees who had at least ten years of service on January 1, 2001, and who were 40 years of age or older as of January 1, 2001. The maximum supplemental retirement contribution will not exceed the annual limit on contributions established by the IRS. The Company will record an annual supplemental retirement credit for the benefit of each participant. The Company’s supplemental retirement contribution and credit for the years ended December 31, 2016 , 2015 and 2014 was $21,000 , $42,000 and $52,000 , respectively. The Company also maintains a deferred compensation plan that is designed to allow officers of Boston Properties, Inc. to defer a portion of their current income on a pre-tax basis and receive a tax-deferred return on these deferrals. The Company’s obligation under the plan is that of an unsecured promise to pay the deferred compensation to the plan participants in the future. At December 31, 2016 and 2015 , the Company had maintained approximately $23.8 million and $20.4 million , respectively, in a separate account, which is not restricted as to its use. The Company’s liability under the plan is equal to the total amount of compensation deferred by the plan participants and earnings on the deferred compensation pursuant to investments elected by the plan participants. The Company’s liability as of December 31, 2016 and 2015 was $23.8 million and $20.4 million , respectively, which are included in the accompanying Consolidated Balance Sheets.

Stock Option and Incentive Plan

Stock Option and Incentive Plan	12 Months Ended
	Dec. 31, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock Option and Incentive Plan	17. Stock Option and Incentive Plan At Boston Properties, Inc.’s 2012 annual meeting of stockholders held on May 15, 2012, its stockholders approved the Boston Properties, Inc. 2012 Stock Option and Incentive Plan (the “2012 Plan”). The 2012 Plan replaced the 1997 Stock Option and Incentive Plan (the “1997 Plan”). The material terms of the 2012 Plan include, among other things: (1) the maximum number of shares of common stock reserved and available for issuance under the 2012 Plan is the sum of (i) 13,000,000 newly authorized shares, plus (ii) the number of shares available for grant under the 1997 Stock Plan immediately prior to the effective date of the 2012 Plan, plus (iii) any shares underlying grants under the 1997 Plan that are forfeited, canceled or terminated (other than by exercise) in the future; (2) “full-value” awards (i.e., awards other than stock options) are multiplied by a 2.32 conversion ratio to calculate the number of shares available under the 2012 Plan that are used for each full-value award, as opposed to a 1.0 conversion ratio for each stock option awarded under the 2012 Plan; (3) shares tendered or held back for taxes will not be added back to the reserved pool under the 2012 Plan; (4) stock options may not be re-priced without stockholder approval; and (5) the term of the 2012 Plan is for ten years from the date of stockholder approval. On January 25, 2016, Boston Properties Inc.’s Compensation Committee approved the 2016 MYLTIP awards under its 2012 Plan to certain officers and employees of Boston Properties, Inc. The 2016 MYLTIP awards utilize 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 (i) the Cohen & Steers Realty Majors Portfolio Index ( 50% weight) and (ii) the NAREIT Office Index adjusted to include Vornado Realty Trust and exclude Boston Properties, Inc. ( 50% weight). Earned awards will range from zero to a maximum of approximately $49.3 million depending on Boston Properties, Inc.’s TSR relative to the two indices, with three tiers (threshold: approximately $9.9 million ; target: approximately $19.7 million ; high: approximately $49.3 million ) and linear interpolation between tiers. Earned awards measured on the basis of relative TSR performance are subject to an absolute TSR component in the form of relatively simple modifiers that (A) reduce the level of earned awards in the event Boston Properties, Inc.’s annualized TSR is less than 0% and (B) cause some awards to be earned in the event Boston Properties, Inc.’s annualized TSR is more than 12% even though on a relative basis alone Boston Properties, Inc.’s TSR would not result in any earned awards. Earned awards (if any) will vest 50% on February 9, 2019 and 50% on February 9, 2020, 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 9, 2019, earned awards will be calculated based on TSR performance up to the date of the change of control. The 2016 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 OP Units and no special distributions. Under the FASB’s ASC 718 “Compensation-Stock Compensation,” the 2016 MYLTIP awards have an aggregate value of approximately $17.3 million , which amount will generally be amortized into earnings over the four -year plan period under the graded vesting method. On February 4, 2016, the measurement period for the Company’s 2013 MYLTIP awards ended and, based on Boston Properties, Inc.’s relative TSR performance, the final awards were determined to be 109.5% of target or an aggregate of approximately $13.5 million . As a result, 205,762 2013 MYLTIP Units were automatically forfeited. On February 6, 2015, the measurement period for the Company’s 2012 OPP Unit awards ended and Boston Properties, Inc.’s TSR performance was sufficient for employees to earn and therefore become eligible to vest in a portion of the 2012 OPP Unit awards. The final outperformance pool was determined to be approximately $32.1 million , or approximately 80% of the total maximum outperformance pool of $40.0 million . As a result, 174,549 2012 OPP Units were automatically forfeited. On March 11, 2013, Boston Properties, Inc. announced that Owen D. Thomas would succeed Mortimer B. Zuckerman as its Chief Executive Officer, effective April 2, 2013. Mr. Zuckerman continued to serve as Executive Chairman for a transition period which was completed effective as of the close of business on December 31, 2014 and thereafter served as the non-executive Chairman of the Board of Boston Properties, Inc. until May 17, 2016. In connection with succession planning, Boston Properties, Inc. and Mr. Zuckerman entered into a Transition Benefits Agreement. Because Mr. Zuckerman remained employed by Boston Properties, Inc. through July 1, 2014, he was entitled to receive on January 1, 2015 a lump sum cash payment of $6.7 million and an equity award with a targeted value of approximately $11.1 million . The cash payment and equity award vested one-third on each of March 10, 2013, October 1, 2013 and July 1, 2014. As a result, the Company recognized approximately $3.9 million of compensation expense during the year ended December 31, 2014. Boston Properties, Inc. issued 22,067 , 34,150 and 23,968 shares of restricted common stock and Boston Properties Limited Partnership issued 147,872 , 190,563 (including 85,962 LTIP Units issued on January 1, 2015 to Mortimer B. Zuckerman, non-executive Chairman of the Board of Boston Properties, Inc., pursuant to the Transition Benefits Agreement dated March 10, 2013) and 127,094 LTIP Units to employees and non-employee directors under the 2012 Plan during the years ended December 31, 2016 , 2015 and 2014 , respectively. Boston Properties, Inc. did not issue any non-qualified stock options under the 2012 Plan during the years ended December 31, 2016 , 2015 and 2014. Boston Properties Limited Partnership issued 485,459 2014 MYLTIP Units to employees under the 2012 Plan during the year ended December 31, 2014. Boston Properties Limited Partnership issued 375,000 2015 MYLTIP Units to employees under the 2012 Plan during the year ended December 31, 2015. Boston Properties Limited Partnership issued 475,004 2016 MYLTIP Units to employees under the 2012 Plan during the year ended December 31, 2016. Employees and directors paid $0.01 per share of restricted common stock and $0.25 per LTIP Unit, OPP Unit and MYLTIP Unit. At the time of an award, LTIP Units do not have full economic parity with OP Units or Common Stock, but can achieve parity over time upon the occurrence of specified events in accordance with partnership tax rules. The aggregate value of the LTIP Units is included in noncontrolling interests in the Consolidated Balance Sheets. Grants of restricted stock and LTIP Units to employees vest in four equal annual installments. Restricted stock is measured at fair value on the date of grant based on the number of shares granted, as adjusted for forfeitures, 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. Non-qualified stock options, which are valued using the Black-Scholes option-pricing model, are recognized as an expense ratably over the corresponding employee service period. As the 2012 OPP Awards, 2013 MYLTIP Awards, 2014 MYLTIP Awards, 2015 MYLTIP Awards and 2016 MYLTIP Awards are subject to both a service condition and a market condition, the Company recognizes the compensation expense related to the 2012 OPP Awards, 2013 MYLTIP Awards, 2014 MYLTIP Awards, 2015 MYLTIP Awards and 2016 MYLTIP Awards 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. 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, non-qualified stock options, LTIP Units, 2012 OPP Units, 2013 MYLTIP Units, 2014 MYLTIP Units, 2015 MYLTIP Units and 2016 MYLTIP Units was approximately $30.6 million , $26.9 million and $26.0 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. For the year ended December 31, 2014, stock-based compensation expense includes approximately $2.5 million , consisting of the acceleration of the expense of Mr. Zuckerman’s stock-based compensation awards and the stock-based compensation awards associated with his transition benefits agreement related to Boston Properties, Inc.’s succession planning. At December 31, 2016 , there was $19.2 million of unrecognized compensation expense related to unvested restricted stock, LTIP Units and 2013 MYLTIP Units and $19.6 million of unrecognized compensation expense related to unvested 2014 MYLTIP Units, 2015 MYLTIP Units and 2016 MYLTIP Units that is expected to be recognized over a weighted-average period of approximately 2.3 years . The shares of restricted stock were valued at approximately $2.5 million ( $113.51 per share weighted-average), $4.8 million ( $140.88 per share weighted-average) and $2.6 million ( $109.27 per share weighted-average) for the years ended December 31, 2016 , 2015 and 2014 , respectively. LTIP Units were valued using a Monte Carlo simulation method model in accordance with the provisions of ASC 718. LTIP Units issued during the years ended December 31, 2016 , 2015 and 2014 were valued at approximately $15.4 million , $13.5 million (excluding the number issued to Mr. Zuckerman, as discussed above) and $12.8 million , respectively. The weighted-average per unit fair value of LTIP Unit grants in 2016 , 2015 and 2014 was $103.83 , $128.94 and $100.61 , respectively. The per unit fair value of each LTIP Unit granted in 2016 , 2015 and 2014 was estimated on the date of grant using the following assumptions; an expected life of 5.7 years , 5.7 years and 5.7 years , a risk-free interest rate of 1.61% , 1.47% and 1.84% and an expected price volatility of 33.0% , 26.0% and 27.0% , respectively. There were no non-qualified stock options granted during the years ended December 31, 2016, 2015 and 2014. A summary of the status of Boston Properties, Inc.’s stock options as of December 31, 2016 , 2015 and 2014 and changes during the years then ended are presented below: Shares Weighted-Average Exercise Price Outstanding at December 31, 2013 558,823 $ 100.43 Exercised (21,459 ) $ 97.04 Canceled (2,444 ) $ 103.57 Special dividend adjustment 18,392 $ 97.22 Outstanding at December 31, 2014 553,312 $ 97.21 Exercised (11,447 ) $ 92.50 Special dividend adjustment 5,264 $ 96.38 Outstanding at December 31, 2015 547,129 $ 96.38 Exercised — $ — Outstanding at December 31, 2016 547,129 $ 96.38 The following table summarizes information about Boston Properties, Inc.’s stock options outstanding at December 31, 2016 : Options Outstanding Options Exercisable Number Outstanding at 12/31/16 Weighted-Average Remaining Contractual Life Exercise Price Number Exercisable at 12/31/16 Exercise Price 118,502 4.1 years $ 86.86 118,502 $ 86.86 54,282 6.3 years $ 95.69 40,711 $ 95.69 206,728 6.1 years $ 98.46 187,530 $ 98.46 167,617 5.1 years $ 100.77 167,617 $ 100.77 The total intrinsic value of the outstanding and exercisable stock options as of December 31, 2016 was approximately $15.2 million . In addition, Boston Properties, Inc. had 465,371 and 411,143 options exercisable at a weighted-average exercise price of $96.10 and $96.91 at December 31, 2015 and 2014, respectively. Boston Properties, Inc. adopted the 1999 Non-Qualified Employee Stock Purchase Plan (the “Stock Purchase Plan”) to encourage the ownership of Common Stock by eligible employees. The Stock Purchase Plan became effective on January 1, 1999 with an aggregate maximum of 250,000 shares of Common Stock available for issuance. The Stock Purchase Plan provides for eligible employees to purchase on the business day immediately following the end of the biannual purchase periods (i.e., January 1-June 30 and July 1-December 31) shares of Common Stock at a purchase price equal to 85% of the average closing prices of the Common Stock during the last ten business days of the purchase period. Boston Properties, Inc. issued 5,695 , 6,199 and 6,964 shares with the weighted average purchase price equal to $109.27 per share, $108.73 per share and $93.37 per share under the Stock Purchase Plan during the years ended December 31, 2016 , 2015 and 2014 , respectively.

Related Party Transactions

Related Party Transactions	180 Months Ended
	Dec. 31, 2015
Related Party Transaction [Line Items]
Related Party Transactions Disclosure [Text Block]	18. Related Party Transactions Prior to joining Boston Properties, Inc. effective January 2, 2014, Mr. John F. Powers provided commercial real estate brokerage services to the Company, on behalf of his prior employer, CBRE, in connection with certain leasing transactions. Mr. Powers received approximately $315,000 , $616,000 and $1,214,000 during the years ended December 31, 2016, 2015 and 2014, respectively, in connection with these transactions. Mr. John F. Powers is an Executive Vice President of Boston Properties, Inc. and the Regional Manager of its New York office. A firm controlled by Mr. Raymond A. Ritchey’s brother was paid aggregate leasing commissions of approximately $374,000 , $384,000 and $674,000 for the years ended December 31, 2016 , 2015 and 2014 , respectively, related to certain exclusive leasing arrangements for certain Northern Virginia properties. Mr. Ritchey is a Senior Executive Vice President of Boston Properties, Inc. In accordance with Boston Properties, Inc.’s 2012 Plan, and as approved by its Board of Directors, six non-employee directors made an election to receive deferred stock units in lieu of cash fees for 2016 . The deferred stock units will be settled in shares of common stock upon the cessation of such director’s service on the Board of Directors of Boston Properties, Inc. As a result of these elections, the aggregate cash fees otherwise payable to a non-employee director during a fiscal quarter are converted into a number of deferred stock units equal to the aggregate cash fees divided by the last reported sales price of a share of Boston Properties, Inc.’s common stock on the last trading of the applicable fiscal quarter. The deferred stock units are also credited with dividend equivalents as dividends are paid by Boston Properties, Inc. On May 20, 2014, in connection with the cessation of a director’s service on the Board of Directors of Boston Properties, Inc., Boston Properties, Inc. issued 7,542 shares of common stock in settlement of the director’s outstanding deferred stock units. On May 17, 2016, in connection with the cessation of a director’s service on the Board of Directors of Boston Properties, Inc., Boston Properties, Inc. issued 1,507 shares of common stock in settlement of the director’s outstanding deferred stock units. At December 31, 2016 and 2015 , Boston Properties, Inc. had outstanding 99,035 and 93,044 deferred stock units, respectively.

Selected Interim Financial Info

Selected Interim Financial Information (unaudited)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information [Text Block]	19. Selected Interim Financial Information (unaudited) Boston Properties, Inc. The tables below reflect Boston Properties, Inc.’s selected quarterly information for the years ended December 31, 2016 and 2015 . 2016 Quarter Ended March 31, June 30, September 30, December 31, (in thousands, except for per share amounts) Total revenue $ 665,985 $ 623,546 $ 625,228 $ 636,061 Income before gains on sales of real estate $ 148,599 $ 117,357 $ 58,521 $ 164,894 Net income attributable to Boston Properties, Inc. common shareholders $ 181,747 $ 96,597 $ 76,753 $ 147,214 Income attributable to Boston Properties, Inc. per share—basic $ 1.18 $ 0.63 $ 0.50 $ 0.96 Income attributable to Boston Properties, Inc. per share—diluted $ 1.18 $ 0.63 $ 0.50 $ 0.96 2015 Quarter Ended March 31, June 30, September 30, December 31, (in thousands, except for per share amounts) Total revenue $ 618,476 $ 618,221 $ 629,884 $ 624,240 Income before gains on sales of real estate $ 114,086 $ 100,739 $ 123,792 $ 85,406 Net income attributable to Boston Properties, Inc. common shareholders $ 171,182 $ 79,460 $ 184,082 $ 137,851 Income attributable to Boston Properties, Inc. per share—basic $ 1.12 $ 0.52 $ 1.20 $ 0.90 Income attributable to Boston Properties, Inc. per share—diluted $ 1.11 $ 0.52 $ 1.20 $ 0.90 Boston Properties Limited Partnership The tables below reflect Boston Properties Limited Partnership’s selected quarterly information for the years ended December 31, 2016 and 2015 . 2016 Quarter Ended March 31, June 30, September 30, December 31, (in thousands, except for per unit amounts) Total revenue $ 665,985 $ 623,546 $ 625,228 $ 636,061 Income before gains on sales of real estate $ 150,586 $ 119,341 $ 63,687 $ 167,384 Net income attributable to Boston Properties Limited Partnership common unitholders $ 207,296 $ 109,938 $ 91,306 $ 166,801 Income attributable to Boston Properties Limited Partnership per unit—basic $ 1.21 $ 0.64 $ 0.53 $ 0.97 Income attributable to Boston Properties Limited Partnership per unit—diluted $ 1.21 $ 0.64 $ 0.53 $ 0.97 2015 Quarter Ended March 31, June 30, September 30, December 31, (in thousands, except for per unit amounts) Total revenue $ 618,476 $ 618,221 $ 629,884 $ 624,240 Income before gains on sales of real estate $ 116,085 $ 102,737 $ 125,790 $ 87,404 Net income attributable to Boston Properties Limited Partnership common unitholders $ 193,369 $ 90,852 $ 207,626 $ 156,901 Income attributable to Boston Properties Limited Partnership per unit—basic $ 1.13 $ 0.53 $ 1.21 $ 0.92 Income attributable to Boston Properties Limited Partnership per unit—diluted $ 1.12 $ 0.53 $ 1.21 $ 0.92

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	20. Subsequent Events On January 25, 2017, Boston Properties, Inc.’s Compensation Committee approved the 2017 Multi-Year Long-Term Incentive Program (the “2017 MYLTIP”) awards under Boston Properties, Inc.’s 2012 Plan to certain officers and employees of Boston Properties, Inc. The 2017 MYLTIP awards utilize Boston Properties, Inc.’s total stockholder return (“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 (i) the Cohen & Steers Realty Majors Portfolio Index ( 50% weight) and (ii) the NAREIT Office Index adjusted to include Vornado Realty Trust ( 50% weight). Earned awards will range from zero to a maximum of approximately $42.7 million depending on Boston Properties, Inc.’s TSR relative to the two indices, with four tiers (threshold: approximately $10.7 million ; target: approximately $21.3 million ; high: approximately $32.0 million ; exceptional: approximately $42.7 million ) and linear interpolation between tiers. Earned awards measured on the basis of relative TSR performance are subject to an absolute TSR component in the form of relatively simple modifiers that (A) reduce the level of earned awards in the event Boston Properties, Inc.’s annualized TSR is less than 0% and (B) cause some awards to be earned in the event Boston Properties, Inc.’s annualized TSR is more than 12% even though on a relative basis alone Boston Properties, Inc.’s TSR would not result in any earned awards. Earned awards (if any) will vest 50% on February 6, 2020 and 50% on February 6, 2021, 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 6, 2020, earned awards will be calculated based on TSR performance up to the date of the change of control. The 2017 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, the 2017 MYLTIP awards have an aggregate value of approximately $17.7 million , which amount will generally be amortized into earnings over the four -year plan period under the graded vesting method. On February 3, 2017, the measurement period for the Company’s 2014 MYLTIP awards ended and, based on Boston Properties, Inc.’s relative TSR performance, the final awards were determined to be 27.7% of target or an aggregate of approximately $3.5 million (after giving effect to voluntary employee separations and the unallocated reserve). As a result, an aggregate of 447,386 2014 MYLTIP Units that had been previously granted were automatically forfeited. On February 3, 2017, Boston Properties, Inc. issued 35,839 shares of restricted common stock and Boston Properties Limited Partnership issued 100,639 LTIP units under the 2012 Plan to certain employees of Boston Properties, Inc.

Real Estate and Accumulated Dep

Real Estate and Accumulated Depreciation	12 Months Ended
	Dec. 31, 2016
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation Disclosure [Text Block]	Boston Properties, Inc. Schedule 3 - Real Estate and Accumulated Depreciation December 31, 2016 (dollars in thousands) Property Name Type Location Encumbrances Original Costs Capitalized Subsequent to Acquisition Land and Improvements Building and Improvements Land Held for Development Development and Construction in Progress Total Accumulated Depreciation Year(s) Built/ Renovated Year(s) Acquired Depreciable Lives (Years) Land Building 767 Fifth Avenue (the General Motors Building) Office New York, NY $ 1,333,625 $ 1,796,252 $ 1,532,654 $ 75,211 $ 1,796,252 $ 1,607,865 $ — $ — $ 3,404,117 $ 189,209 1968 2013 (1) Prudential Center Office Boston, MA — 92,077 734,594 656,606 115,638 1,214,787 — 152,852 1,483,277 482,661 1965/1993/2002/2016 1998/1999/2000 (1) Embarcadero Center Office San Francisco, CA — 179,697 847,410 343,726 195,987 1,174,846 — — 1,370,833 560,416 1970/1989 1998-1999 (1) 399 Park Avenue Office New York, NY — 339,200 700,358 132,062 354,107 817,513 — — 1,171,620 287,748 1961 2002 (1) 200 Clarendon Street and Garage Office Boston, MA — 219,543 667,884 115,996 219,616 777,557 6,250 — 1,003,423 140,629 1976 2010 (1) 601 Lexington Avenue Office New York, NY 684,858 241,600 494,782 196,359 289,639 620,487 — 22,615 932,741 239,984 1977/1997 2001 (1) 250 West 55th Street Office New York, NY — 285,263 603,167 35,668 285,263 638,835 — — 924,098 49,852 2014 2007 (1) Times Square Tower Office New York, NY — 165,413 380,438 87,583 169,193 464,241 — — 633,434 178,904 2004 2000 (1) Carnegie Center Office Princeton, NJ — 105,107 377,259 149,576 106,734 522,654 2,554 — 631,942 211,035 1983-2016 1998/1999/2000/2007/2014 (1) 100 Federal Street Office Boston, MA — 131,067 435,954 38,611 131,067 474,565 — — 605,632 77,409 1971-1975 2012 (1) Atlantic Wharf Office Boston, MA — 63,988 454,537 17,442 63,988 471,979 — — 535,967 85,984 2011 2007 (1) Fountain Square Office Reston, VA — 56,853 306,298 17,748 56,853 320,759 3,287 — 380,899 50,106 1986-1990 2012 (1) 510 Madison Avenue Office New York, NY — 103,000 253,665 21,952 103,000 275,617 — — 378,617 44,515 2012 2010 (1) 599 Lexington Avenue Office New York, NY — 81,040 100,507 169,222 87,852 262,917 — — 350,769 168,776 1986 1997 (1) 680 Folsom Street Office San Francisco, CA — 72,545 219,766 7,352 72,545 227,118 — — 299,663 21,845 2014 2012 (1) South of Market and Democracy Tower Office Reston, VA — 13,603 237,479 15,455 13,687 252,850 — — 266,537 79,868 2008-2009 2003 (1) 601 Massachusetts Avenue Office Washington, DC — 95,310 165,173 12 95,322 165,173 — — 260,495 6,534 2016 2008 (1) Bay Colony Corporate Center Office Waltham, MA — 18,789 148,451 68,371 18,789 216,822 — — 235,611 46,015 1985-1989 2011 (1) Gateway Center Office San Francisco, CA — 28,255 139,245 55,680 30,627 192,553 — — 223,180 98,003 1984/1986/2002 1999 (1) 535 Mission Street Office San Francisco, CA — 40,933 148,378 2,015 40,933 150,393 — — 191,326 8,844 2015 2013 (1) 2200 Pennsylvania Avenue Office Washington, DC — — 183,541 5,047 — 188,588 — — 188,588 39,956 2011 2008 (1) Mountain View Research Park Office Mountain View, CA — 95,066 68,373 6,491 95,066 74,864 — — 169,930 12,849 1977-1981/2007-2013 2013 (1) Reservoir Place Office Waltham, MA — 18,605 92,619 53,163 20,118 129,712 — 14,557 164,387 61,362 1955/1987 1997/1998 (1) 1330 Connecticut Avenue Office Washington, DC — 25,982 82,311 32,276 27,135 113,434 — — 140,569 34,137 1984 2004 (1) 1333 New Hampshire Avenue Office Washington, DC — 34,032 85,660 11,147 35,382 95,457 — — 130,839 37,996 1996 2003 (1) Kingstowne Towne Center Office Alexandria, VA — 18,021 109,038 1,083 18,062 110,080 — — 128,142 36,551 2003-2006 2007 (1) Capital Gallery Office Washington, DC — 4,725 29,565 89,028 8,662 114,656 — — 123,318 61,569 1981/2006 2007 (1) Boston Properties, Inc. Schedule 3 - Real Estate and Accumulated Depreciation December 31, 2016 (dollars in thousands) Property Name Type Location Encumbrances Original Costs Capitalized Subsequent to Acquisition Land and Improvements Building and Improvements Land Held for Development Development and Construction in Progress Total Accumulated Depreciation Year(s) Built/ Renovated Year(s) Acquired Depreciable Lives (Years) Land Building One Freedom Square Office Reston, VA — 9,929 84,504 28,646 11,293 111,786 — — 123,079 45,550 2000 2003 (1) Weston Corporate Center Office Weston, MA — 25,753 92,312 (123 ) 25,854 92,088 — — 117,942 20,074 2010 2001 (1) Two Freedom Square Office Reston, VA — 13,930 77,739 22,756 15,420 99,005 — — 114,425 44,569 2001 2003 (1) One and Two Reston Overlook Office Reston, VA — 16,456 66,192 24,634 16,179 91,103 — — 107,282 40,513 1999 2000 (1) Discovery Square Office Reston, VA — 11,198 71,782 22,642 12,533 93,089 — — 105,622 39,605 2001 2003 (1) 140 Kendrick Street Office Needham, MA — 18,095 66,905 15,466 19,092 81,374 — — 100,466 26,141 2000 2004 (1) 355 Main Street Office Cambridge, MA — 18,863 53,346 27,658 21,173 78,694 — — 99,867 25,345 1981/1996/2013 2006 (1) 90 Broadway Office Cambridge, MA — 19,104 52,078 17,048 20,785 67,445 — — 88,230 17,087 1983/1998/2013 2006 (1) 10 CityPoint Office Waltham, MA — 1,953 85,752 163 2,116 85,752 — — 87,868 1,601 2016 1997 (1) 230 CityPoint Office Waltham, MA — 13,189 49,823 20,187 13,593 69,606 — — 83,199 23,437 1992 2005 (1) Waltham Weston Corporate Center Office Waltham, MA — 10,385 60,694 10,889 11,097 70,871 — — 81,968 27,310 2003 1999 (1) 77 CityPoint Office Waltham, MA — 13,847 60,383 5,703 13,873 66,060 — — 79,933 20,981 2008 2001 (1) 3625-3635 Peterson Way Office Santa Clara, CA — 63,206 14,879 31 63,206 14,879 31 — 78,116 2,093 1979 2016 (1) North First Business Park Office San Jose, CA — 58,402 13,069 3,932 23,377 16,116 35,910 — 75,403 15,811 1981 2007 (1) 2440 West El Camino Real Office Mountain View, CA — 16,741 51,285 1,814 16,741 53,099 — — 69,840 9,817 1987/2003 2011 (1) 300 Binney Street Office Cambridge, MA — 18,080 51,262 140 18,080 51,402 — — 69,482 6,059 2013 2009 (1) Reston Corporate Center Office Reston, VA — 9,135 50,857 6,256 10,148 56,100 — — 66,248 25,244 1984 1998 (1) Wisconsin Place Office Chevy Chase, MD — — 53,349 9,884 — 63,233 — — 63,233 16,406 2009 2004 (1) New Dominion Technology Park, Bldg. Two Office Herndon, VA — 5,584 51,868 4,094 6,510 55,036 — — 61,546 21,908 2004 1998 (1) 200 West Street Office Waltham, MA — 16,148 24,983 10,102 16,813 34,420 — — 51,233 19,535 1999 1997 (1) New Dominion Technology Park, Bldg. One Office Herndon, VA 35,485 3,880 43,227 3,883 4,583 46,407 — — 50,990 24,362 2001 1998 (1) Sumner Square Office Washington, DC — 624 28,745 19,428 1,478 47,319 — — 48,797 22,237 1985 1999 (1) University Place Office Cambridge, MA 9,119 — 37,091 9,501 390 46,202 — — 46,592 25,207 1985 1998 (1) 2600 Tower Oaks Boulevard Office Rockville, MD — 4,243 31,125 9,081 4,785 39,664 — — 44,449 19,801 2001 1998 (1) 255 Main Street Office Cambridge, MA — 134 25,110 17,087 548 41,783 — — 42,331 27,499 1987 1997 (1) Quorum Office Park Office Chelmsford, MA — 3,750 32,454 5,813 5,187 36,830 — — 42,017 15,633 2001 2000 (1) 500 E Street Office Washington, DC — 109 22,420 13,219 2,379 33,369 — — 35,748 22,987 1987 1997 (1) 150 Broadway Office Cambridge, MA — 850 25,042 8,623 1,323 33,192 — — 34,515 15,545 1999 1997 (1) 325 Main Street Office Cambridge, MA — 174 12,200 12,256 965 23,665 — — 24,630 12,266 1987/2013 1997 (1) 105 Broadway Office Cambridge, MA — 1,299 12,943 7,198 2,395 19,045 — — 21,440 13,018 1990 1997 (1) Lexington Office Park Office Lexington, MA — 998 1,426 17,481 1,264 18,641 — — 19,905 12,490 1982 1997 (1) 40 Shattuck Road Office Andover, MA — 709 14,740 3,368 893 17,924 — — 18,817 7,505 2001 1997 (1) 201 Spring Street Office Lexington, MA — 2,849 15,303 14 3,124 15,042 — — 18,166 7,462 1997 1997 (1) The Point Office Waltham, MA — 6,395 10,040 408 6,480 10,363 — — 16,843 397 2015 2007 (1) 92-100 Hayden Avenue Office Lexington, MA — 594 6,748 8,181 802 14,721 — — 15,523 12,062 1985 1997 (1) 91 Hartwell Avenue Office Lexington, MA — 784 6,464 8,254 941 14,561 — — 15,502 9,062 1985 1997 (1) Boston Properties, Inc. Schedule 3 - Real Estate and Accumulated Depreciation December 31, 2016 (dollars in thousands) Property Name Type Location Encumbrances Original Costs Capitalized Subsequent to Acquisition Land and Improvements Building and Improvements Land Held for Development Development and Construction in Progress Total Accumulated Depreciation Year(s) Built/ Renovated Year(s) Acquired Depreciable Lives (Years) Land Building 690 Folsom Street Office San Francisco, CA — 3,219 11,038 1,157 3,219 12,195 — — 15,414 801 2015 2012 (1) 145 Broadway Office Cambridge, MA — 121 5,535 7,173 324 10,637 — 1,868 12,829 8,676 1984 1997 (1) 181 Spring Street Office Lexington, MA — 1,066 9,520 2,195 1,160 11,621 — — 12,781 4,876 1999 1997 (1) 195 West Street Office Waltham, MA — 1,611 6,652 4,340 1,858 10,745 — — 12,603 7,517 1990 1997 (1) 33 Hayden Avenue Office Lexington, MA — 266 3,234 8,787 425 11,862 — — 12,287 7,612 1979 1997 (1) 7501 Boston Boulevard, Building Seven Office Springfield, VA — 665 9,273 535 791 9,682 — — 10,473 4,596 1997 1997 (1) 7435 Boston Boulevard, Building One Office Springfield, VA — 392 3,822 5,116 659 8,671 — — 9,330 6,356 1982 1997 (1) 250 Binney Street Office Cambridge, MA — 110 4,483 3,593 273 7,913 — — 8,186 4,684 1983 1997 (1) 7450 Boston Boulevard, Building Three Office Springfield, VA — 1,165 4,681 1,807 1,430 6,223 — — 7,653 3,321 1987 1998 (1) 8000 Grainger Court, Building Five Office Springfield, VA — 366 4,282 2,607 601 6,654 — — 7,255 5,416 1984 1997 (1) 453 Ravendale Drive Office Mountain View, CA — 5,477 1,090 408 5,477 1,498 — — 6,975 338 1977 2012 (1) 7500 Boston Boulevard, Building Six Office Springfield, VA — 138 3,749 2,487 406 5,968 — — 6,374 4,538 1985 1997 (1) 17 Hartwell Avenue Office Lexington, MA — 26 150 6,109 65 6,220 — — 6,285 552 1968 1997 (1) 7601 Boston Boulevard, Building Eight Office Springfield, VA — 200 878 5,047 551 5,574 — — 6,125 4,043 1986 1997 (1) 7300 Boston Boulevard, Building Thirteen Office Springfield, VA — 608 4,773 709 661 5,429 — — 6,090 5,012 2002 1997 (1) 8000 Corporate Court, Building Eleven Office Springfield, VA — 136 3,071 1,615 775 4,047 — — 4,822 2,784 1989 1997 (1) 7375 Boston Boulevard, Building Ten Office Springfield, VA — 23 2,685 912 93 3,527 — — 3,620 2,472 1988 1997 (1) 7374 Boston Boulevard, Building Four Office Springfield, VA — 241 1,605 1,738 398 3,186 — — 3,584 2,452 1984 1997 (1) 7451 Boston Boulevard, Building Two Office Springfield, VA — 249 1,542 1,659 613 2,837 — — 3,450 2,330 1982 1997 (1) 32 Hartwell Avenue Office Lexington, MA — 168 1,943 1,012 314 2,809 — — 3,123 1,905 1968/1979/1987 1997 (1) 164 Lexington Road Office Billerica, MA — 592 1,370 319 643 1,638 — — 2,281 827 1982 1997 (1) The Avant at Reston Town Center Residential Reston, VA — 20,350 91,995 815 20,350 92,810 — — 113,160 7,306 2014 2010 (1) The Lofts at Atlantic Wharf Residential Boston, MA — 3,529 54,891 1,663 3,529 56,554 — — 60,083 8,105 2011 2007 (1) Boston Marriott Cambridge Hotel Cambridge, MA — 478 37,918 37,067 1,201 74,262 — — 75,463 50,954 1986 1997 (1) Kendall Center Green Garage Garage Cambridge, MA — — 35,035 7,391 103 42,323 — — 42,426 9,334 1984 2006 (1) Kendall Center Yellow Garage Garage Cambridge, MA — 1,256 15,697 1,571 1,434 17,090 — — 18,524 4,723 2006 2004 (1) Kendall Center Blue Garage Garage Cambridge, MA — 1,163 11,633 2,770 1,579 13,987 — — 15,566 9,325 1990 1997 (1) Salesforce Tower Development San Francisco, CA — — — 723,866 — — — 723,866 723,866 — N/A 2013 N/A Signature at Reston (formerly Reston Signature Site) Development Reston, VA — — — 96,444 — — — 96,444 96,444 — N/A 2013 N/A 191 Spring Street Development Lexington, MA — 2,850 27,166 3,134 3,151 28,576 — 1,423 33,150 21,660 1971/1995 1997 (1) Boston Properties, Inc. Schedule 3 - Real Estate and Accumulated Depreciation December 31, 2016 (dollars in thousands) Property Name Type Location Encumbrances Original Costs Capitalized Subsequent to Acquisition Land and Improvements Building and Improvements Land Held for Development Development and Construction in Progress Total Accumulated Depreciation Year(s) Built/ Renovated Year(s) Acquired Depreciable Lives (Years) Land Building Proto at Cambridge (formerly Cambridge Residential / 88 Ames) Development Cambridge, MA — — — 24,334 — — — 24,334 24,334 — N/A 2015 N/A Springfield Metro Center Land Springfield, VA — — — 35,430 — — 35,430 — 35,430 — N/A 2007 N/A Tower Oaks Master Plan Land Rockville, MD — — — 29,209 — — 29,209 — 29,209 — N/A 1998 N/A Plaza at Almaden Land San Jose, CA — — — 29,081 — — 29,081 — 29,081 — N/A 2006 N/A 6601 & 6605 Springfield Center Drive Land Springfield, VA — — — 13,866 — — 13,866 — 13,866 — N/A 2007 N/A 214 Third Avenue Land Waltham, MA — — — 13,795 — 146 13,649 — 13,795 — N/A 2006 N/A 103 Fourth Avenue Land Waltham, MA — — — 12,052 — 49 12,003 — 12,052 — N/A 2007 N/A 20 CityPoint Land Waltham, MA — — — 11,666 — — 11,666 — 11,666 — N/A 2007 N/A Reston Gateway Land Reston, VA — — — 10,841 — — 10,841 — 10,841 — N/A 1998 N/A Reston Eastgate Land Reston, VA — — — 9,906 — — 9,906 — 9,906 — N/A 2001 N/A Crane Meadow Land Marlborough, MA — — — 8,754 — — 8,754 — 8,754 — N/A 2000 N/A Washingtonian North Land Gaithersburg, MD — — — 7,697 — — 7,697 — 7,697 — N/A 1998 N/A Kendall Center Master Plan Land Cambridge, MA — — — 4,062 — — 4,062 — 4,062 — N/A N/A N/A Fourth and Harrison Land San Francisco, CA — — — 3,936 — — 3,936 — 3,936 — N/A N/A N/A North First Master Plan Land San Jose, CA — — — 3,014 — — 3,014 — 3,014 — N/A 2007 N/A Broad Run Business Park Land Loudoun County, VA — — — 2,694 — — 2,694 — 2,694 — N/A 1998 N/A MacArthur Station Land Oakland, CA — — — 1,316 — — 1,316 — 1,316 — N/A N/A N/A 30 Shattuck Road Land Andover, MA — — — 1,214 — — 1,214 — 1,214 — N/A 1997 N/A 2100 Pennsylvania Avenue Land Washington, DC — — — 286 — — 286 — 286 — N/A N/A N/A $ 2,063,087 (2 ) $ 4,759,821 $ 11,416,957 $ 3,937,798 $ 4,879,020 $ 13,950,941 $ 246,656 (3 ) $ 1,037,959 $ 20,114,576 $ 4,201,891 Note: Total Real Estate does not include Furniture, Fixtures and Equipment totaling approximately $32,687 . Accumulated Depreciation does not include approximately $20,344 of accumulated depreciation related to Furniture, Fixtures and Equipment. The aggregate cost and accumulated depreciation for tax purposes was approximately $15.8 billion and $3.2 billion , respectively. (1) Depreciation of the buildings and improvements are calculated over lives ranging from the life of the lease to 40 years. (2) Includes the unamortized balance of the historical fair value adjustment and unamortized deferred financing costs totaling approximately $33.8 million and $(2.4) million , respectively. (3) Includes pre-development costs. Boston Properties, Inc. Real Estate and Accumulated Depreciation December 31, 2016 , 2015 and 2014 (dollars in thousands) A summary of activity for real estate and accumulated depreciation is as follows: 2016 2015 2014 Real Estate: Balance at the beginning of the year $ 19,451,683 $ 19,208,417 $ 18,953,601 Additions to/improvements of real estate 977,287 700,792 594,296 Assets sold/written-off (314,394 ) (457,526 ) (339,480 ) Balance at the end of the year $ 20,114,576 $ 19,451,683 $ 19,208,417 Accumulated Depreciation: Balance at the beginning of the year $ 3,905,940 $ 3,529,978 $ 3,145,701 Depreciation expense 560,024 486,450 456,176 Assets sold/written-off (264,073 ) (110,488 ) (71,899 ) Balance at the end of the year $ 4,201,891 $ 3,905,940 $ 3,529,978 Note: Real Estate and Accumulated Depreciation amounts do not include Furniture, Fixtures and Equipment.
Boston Properties Limited Partnership
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation Disclosure [Text Block]	Boston Properties Limited Partnership Schedule 3—Real Estate and Accumulated Depreciation December 31, 2016 (dollars in thousands) Original Costs Capitalized Subsequent to Acquisition Land and Improvements Building and Improvements Land Held for Development Development and Construction in Progress Total Accumulated Depreciation Year(s) Built/ Renovated Year(s) Acquired Depreciable Lives (Years) Property Name Type Location Encumbrances Land Building 767 Fifth Avenue (the General Motors Building) Office New York, NY $ 1,333,625 $ 1,796,252 $ 1,532,654 $ 75,211 $ 1,796,252 $ 1,607,865 $ — $ — $ 3,404,117 $ 189,209 1968 2013 (1) Prudential Center Office Boston, MA — 92,077 734,594 596,236 100,540 1,169,515 — 152,852 1,422,907 470,161 1965/1993/2002/2016 1998/1999/2000 (1) Embarcadero Center Office San Francisco, CA — 179,697 847,410 281,345 180,420 1,128,032 — — 1,308,452 547,434 1970/1989 1998-1999 (1) 399 Park Avenue Office New York, NY — 339,200 700,358 72,454 339,200 772,812 — — 1,112,012 275,380 1961 2002 (1) 200 Clarendon Street and Garage Office Boston, MA — 219,543 667,884 115,996 219,616 777,557 6,250 — 1,003,423 140,629 1976 2010 (1) 250 West 55th Street Office New York, NY — 285,263 603,167 35,668 285,263 638,835 — — 924,098 49,852 2014 2007 (1) 601 Lexington Avenue Office New York, NY 684,858 241,600 494,782 159,273 279,281 593,759 — 22,615 895,655 232,590 1977/1997 2001 (1) Carnegie Center Office Princeton, NJ — 105,107 377,259 132,258 102,403 509,667 2,554 — 614,624 207,448 1983-2016 1998/1999/2000/2007/2014 (1) 100 Federal Street Office Boston, MA — 131,067 435,954 38,611 131,067 474,565 — — 605,632 77,409 1971-1975 2012 (1) Times Square Tower Office New York, NY — 165,413 380,438 49,604 159,694 435,761 — — 595,455 171,039 2004 2000 (1) Atlantic Wharf Office Boston, MA — 63,988 454,537 17,442 63,988 471,979 — — 535,967 85,984 2011 2007 (1) Fountain Square Office Reston, VA — 56,853 306,298 17,748 56,853 320,759 3,287 — 380,899 50,106 1986-1990 2012 (1) 510 Madison Avenue Office New York, NY — 103,000 253,665 21,952 103,000 275,617 — — 378,617 44,515 2012 2010 (1) 599 Lexington Avenue Office New York, NY — 81,040 100,507 141,980 81,040 242,487 — — 323,527 163,140 1986 1997 (1) 680 Folsom Street Office San Francisco, CA — 72,545 219,766 7,352 72,545 227,118 — — 299,663 21,845 2014 2012 (1) South of Market and Democracy Tower Office Reston, VA — 13,603 237,479 15,119 13,603 252,598 — — 266,201 79,814 2008-2009 2003 (1) 601 Massachusetts Avenue Office Washington, DC — 95,310 165,173 — 95,310 165,173 — — 260,483 6,534 2016 2008 (1) Bay Colony Corporate Center Office Waltham, MA — 18,789 148,451 68,371 18,789 216,822 — — 235,611 46,015 1985-1989 2011 (1) Gateway Center Office San Francisco, CA — 28,255 139,245 49,291 29,029 187,762 — — 216,791 96,681 1984/1986/2002 1999 (1) 535 Mission Street Office San Francisco, CA — 40,933 148,378 2,015 40,933 150,393 — — 191,326 8,844 2015 2013 (1) 2200 Pennsylvania Avenue Office Washington, DC — — 183,541 5,047 — 188,588 — — 188,588 39,956 2011 2008 (1) Mountain View Research Park Office Mountain View, CA — 95,066 68,373 6,491 95,066 74,864 — — 169,930 12,849 1977-1981/2007-2013 2013 (1) Reservoir Place Office Waltham, MA — 18,605 92,619 49,088 19,099 126,656 — 14,557 160,312 60,518 1955/1987 1997/1998 (1) 1330 Connecticut Avenue Office Washington, DC — 25,982 82,311 27,663 25,982 109,974 — — 135,956 33,179 1984 2004 (1) Kingstowne Towne Center Office Alexandria, VA — 18,021 109,038 919 18,021 109,957 — — 127,978 36,524 2003-2006 2007 (1) 1333 New Hampshire Avenue Office Washington, DC — 34,032 85,660 5,753 34,032 91,413 — — 125,445 36,878 1996 2003 (1) Weston Corporate Center Office Weston, MA — 25,753 92,312 (123 ) 25,854 92,088 — — 117,942 20,074 2010 2001 (1) One Freedom Square Office Reston, VA — 9,929 84,504 23,009 9,883 107,559 — — 117,442 44,381 2000 2003 (1) Capital Gallery Office Washington, DC — 4,725 29,565 78,897 6,128 107,059 — — 113,187 59,469 1981/2006 2007 (1) Two Freedom Square Office Reston, VA — 13,930 77,739 16,544 13,866 94,347 — — 108,213 43,283 2001 2003 (1) One and Two Reston Overlook Office Reston, VA — 16,456 66,192 20,216 15,074 87,790 — — 102,864 39,598 1999 2000 (1) Boston Properties Limited Partnership Schedule 3—Real Estate and Accumulated Depreciation December 31, 2016 (dollars in thousands) Original Costs Capitalized Subsequent to Acquisition Land and Improvements Building and Improvements Land Held for Development Development and Construction in Progress Total Accumulated Depreciation Year(s) Built/ Renovated Year(s) Acquired Depreciable Lives (Years) Property Name Type Location Encumbrances Land Building Discovery Square Office Reston, VA — 11,198 71,782 17,097 11,146 88,931 — — 100,077 38,454 2001 2003 (1) 355 Main Street Office Cambridge, MA — 18,863 53,346 27,360 21,098 78,471 — — 99,569 25,286 1981/1996/2013 2006 (1) 140 Kendrick Street Office Needham, MA — 18,095 66,905 11,476 18,095 78,381 — — 96,476 25,315 2000 2004 (1) 90 Broadway Office Cambridge, MA — 19,104 52,078 16,869 20,741 67,310 — — 88,051 17,056 1983/1998/2013 2006 (1) 10 CityPoint Office Waltham, MA — 1,953 85,752 — 1,953 85,752 — — 87,705 1,601 2016 1997 (1) 230 CityPoint Office Waltham, MA — 13,189 49,823 18,570 13,189 68,393 — — 81,582 23,106 1992 2005 (1) 77 CityPoint Office Waltham, MA — 13,847 60,383 5,598 13,847 65,981 — — 79,828 20,963 2008 2001 (1) Waltham Weston Corporate Center Office Waltham, MA — 10,385 60,694 7,902 10,350 68,631 — — 78,981 26,690 2003 1999 (1) 3625-3635 Peterson Way Office Santa Clara, CA — 63,206 14,879 31 63,206 14,879 31 — 78,116 2,093 1979 2016 (1) North First Business Park Office San Jose, CA — 58,402 13,069 3,909 23,371 16,099 35,910 — 75,380 15,811 1981 2007 (1) 2440 West El Camino Real Office Mountain View, CA — 16,741 51,285 1,814 16,741 53,099 — — 69,840 9,817 1987/2003 2011 (1) 300 Binney Street Office Cambridge, MA — 18,080 51,262 140 18,080 51,402 — — 69,482 6,059 2013 2009 (1) Reston Corporate Center Office Reston, VA — 9,135 50,857 3,645 9,496 54,141 — — 63,637 24,703 1984 1998 (1) Wisconsin Place Office Chevy Chase, MD — — 53,349 9,884 — 63,233 — — 63,233 16,406 2009 2004 (1) New Dominion Technology Park, Bldg. Two Office Herndon, VA — 5,584 51,868 349 5,574 52,227 — — 57,801 21,128 2004 1998 (1) 200 West Street Office Waltham, MA — 16,148 24,983 7,441 16,148 32,424 — — 48,572 18,983 1999 1997 (1) New Dominion Technology Park, Bldg. One Office Herndon, VA 35,485 3,880 43,227 1,073 3,880 44,300 — — 48,180 23,779 2001 1998 (1) Sumner Square Office Washington, DC — 624 28,745 17,348 958 45,759 — — 46,717 21,809 1985 1999 (1) University Place Office Cambridge, MA 9,119 — 37,091 8,051 27 45,115 — — 45,142 24,910 1985 1998 (1) 2600 Tower Oaks Boulevard Office Rockville, MD — 4,243 31,125 6,918 4,244 38,042 — — 42,286 19,351 2001 1998 (1) 255 Main Street Office Cambridge, MA — 134 25,110 15,431 134 40,541 — — 40,675 27,158 1987 1997 (1) Quorum Office Park Office Chelmsford, MA — 3,750 32,454 4,115 4,762 35,557 — — 40,319 15,282 2001 2000 (1) 150 Broadway Office Cambridge, MA — 850 25,042 6,618 822 31,688 — — 32,510 15,127 1999 1997 (1) 500 E Street Office Washington, DC — 109 22,420 9,979 1,569 30,939 — — 32,508 22,318 1987 1997 (1) 325 Main Street Office Cambridge, MA — 174 12,200 11,485 772 23,087 — — 23,859 12,104 1987/2013 1997 (1) 105 Broadway Office Cambridge, MA — 1,299 12,943 5,092 1,868 17,466 — — 19,334 12,580 1990 1997 (1) Lexington Office Park Office Lexington, MA — 998 1,426 16,717 1,073 18,068 — — 19,141 12,335 1982 1997 (1) 40 Shattuck Road Office Andover, MA — 709 14,740 2,632 709 17,372 — — 18,081 7,352 2001 1997 (1) 201 Spring Street Office Lexington, MA — 2,849 15,303 (1,085 ) 2,849 14,218 — — 17,067 7,233 1997 1997 (1) The Point Office Waltham, MA — 6,395 10,040 408 6,480 10,363 — — 16,843 397 2015 2007 (1) 690 Folsom Street Office San Francisco, CA — 3,219 11,038 1,157 3,219 12,195 — — 15,414 801 2015 2012 (1) 91 Hartwell Avenue Office Lexington, MA — 784 6,464 7,627 784 14,091 — — 14,875 8,930 1985 1997 (1) 92-100 Hayden Avenue Office Lexington, MA — 594 6,748 7,452 619 14,175 — — 14,794 11,910 1985 1997 (1) 181 Spring Street Office Lexington, MA — 1,066 9,520 1,818 1,066 11,338 — — 12,404 4,798 1999 1997 (1) 145 Broadway Office Cambridge, MA — 121 5,535 6,360 121 10,027 — 1,868 12,016 8,385 1984 1997 (1) Boston Properties Limited Partnership Schedule 3—Real Estate and Accumulated Depreciation December 31, 2016 (dollars in thousands) Original Costs Capitalized Subsequent to Acquisition Land and Improvements Building and Improvements Land Held for Development Development and Construction in Progress Total Accumulated Depreciation Year(s) Built/ Renovated Year(s) Acquired Depreciable Lives (Years) Property Name Type Location Encumbrances Land Building 33 Hayden Avenue Office Lexington, MA — 266 3,234 8,150 266 11,384 — — 11,650 7,480 1979 1997 (1) 195 West Street Office Waltham, MA — 1,611 6,652 3,351 1,611 10,003 — — 11,614 7,309 1990 1997 (1) 7501 Boston Boulevard, Building Seven Office Springfield, VA — 665 9,273 30 665 9,303 — — 9,968 4,490 1997 1997 (1) 7435 Boston Boulevard, Building One Office Springfield, VA — 392 3,822 4,423 486 8,151 — — 8,637 6,213 1982 1997 (1) 250 Binney Street Office Cambridge, MA — 110 4,483 2,939 110 7,422 — — 7,532 4,552 1983 1997 (1) 7450 Boston Boulevard, Building Three Office Springfield, VA — 1,165 4,681 1,393 1,327 5,912 — — 7,239 3,232 1987 1998 (1) 453 Ravendale Drive Office Mountain View, CA — 5,477 1,090 408 5,477 1,498 — — 6,975 338 1977 2012 (1) 8000 Grainger Court, Building Five Office Springfield, VA — 366 4,282 2,013 453 6,208 — — 6,661 5,294 1984 1997 (1) 17 Hartwell Avenue Office Lexington, MA — 26 150 5,952 26 6,102 — — 6,128 519 1968 1997 (1) 7300 Boston Boulevard, Building Thirteen Office Springfield, VA — 608 4,773 497 608 5,270 — — 5,878 4,968 2002 1997 (1) 7500 Boston Boulevard, Building Six Office Springfield, VA — 138 3,749 1,954 273 5,568 — — 5,841 4,428 1985 1997 (1) 7601 Boston Boulevard, Building Eight Office Springfield, VA — 200 878 4,354 378 5,054 — — 5,432 3,900 1986 1997 (1) 8000 Corporate Court, Building Eleven Office Springfield, VA — 136 3,071 1,264 687 3,784 — — 4,471 2,708 1989 1997 (1) 7375 Boston Boulevard, Building Ten Office Springfield, VA — 23 2,685 731 47 3,392 — — 3,439 2,437 1988 1997 (1) 7374 Boston Boulevard, Building Four Office Springfield, VA — 241 1,605 1,355 303 2,898 — — 3,201 2,375 1984 1997 (1) 7451 Boston Boulevard, Building Two Office Springfield, VA — 249 1,542 1,346 535 2,602 — — 3,137 2,264 1982 1997 (1) 32 Hartwell Avenue Office Lexington, MA — 168 1,943 426 168 2,369 — — 2,537 1,782 1968/1979/1987 1997 (1) 164 Lexington Road Office Billerica, MA — 592 1,370 117 592 1,487 — — 2,079 782 1982 1997 (1) The Avant at Reston Town Center Residential Reston, VA — 20,350 91,995 815 20,350 92,810 — — 113,160 7,306 2014 2010 (1) The Lofts at Atlantic Wharf Residential Boston, MA — 3,529 54,891 1,663 3,529 56,554 — — 60,083 8,105 2011 2007 (1) Boston Marriott Cambridge Hotel Cambridge, MA — 478 37,918 34,176 478 72,094 — — 72,572 50,357 1986 1997 (1) Kendall Center Green Garage Garage Cambridge, MA — — 35,035 6,977 — 42,012 — — 42,012 9,250 1984 2006 (1) Kendall Center Yellow Garage Garage Cambridge, MA — 1,256 15,697 859 1,256 16,556 — — 17,812 4,580 2006 2004 (1) Kendall Center Blue Garage Garage Cambridge, MA — 1,163 11,633 1,105 1,163 12,738 — — 13,901 8,982 1990 1997 (1) Salesforce Tower Development San Francisco, CA — — — 723,866 — — — 723,866 723,866 — N/A 2013 N/A Signature at Reston (formerly Reston Signature Site) Development Reston, VA — — — 96,444 — — — 96,444 96,444 — N/A 2013 N/A 191 Spring Street Development Lexington, MA — 2,850 27,166 1,935 2,850 27,678 — 1,423 31,951 21,001 1971/1995 1997 (1) Boston Properties Limited Partnership Schedule 3—Real Estate and Accumulated Depreciation December 31, 2016 (dollars in thousands) Original Costs Capitalized Subsequent to Acquisition Land and Improvements Building and Improvements Land Held for Development Development and Construction in Progress Total Accumulated Depreciation Year(s) Built/ Renovated Year(s) Acquired Depreciable Lives (Years) Property Name Type Location Encumbrances Land Building Proto at Cambridge (formerly Cambridge Residential / 88 Ames) Development Cambridge, MA — — — 24,334 — — — 24,334 24,334 — N/A 2015 N/A Springfield Metro Center Land Springfield, VA — — — 35,430 — — 35,430 — 35,430 — N/A 2007 N/A Tower Oaks Master Plan Land Rockville, MD — — — 29,209 — — 29,209 — 29,209 — N/A 1998 N/A Plaza at Almaden Land San Jose, CA — — — 29,081 — — 29,081 — 29,081 — N/A 2006 N/A 6601 & 6605 Springfield Center Drive Land Springfield, VA — — — 13,866 — — 13,866 — 13,866 — N/A 2007 N/A 214 Third Avenue Land Waltham, MA — — — 13,795 — 146 13,649 — 13,795 — N/A 2006 N/A 103 Fourth Avenue Land Waltham, MA — — — 12,052 — 49 12,003 — 12,052 — N/A 2007 N/A 20 CityPoint Land Waltham, MA — — — 11,666 — — 11,666 — 11,666 — N/A 2007 N/A Reston Gateway Land Reston, VA — — — 10,841 — — 10,841 — 10,841 — N/A 1998 N/A Reston Eastgate Land Reston, VA — — — 9,906 — — 9,906 — 9,906 — N/A 2001 N/A Crane Meadow Land Marlborough, MA — — — 8,754 — — 8,754 — 8,754 — N/A 2000 N/A Washingtonian North Land Gaithersburg, MD — — — 7,697 — — 7,697 — 7,697 — N/A 1998 N/A Kendall Center Master Plan Land Cambridge, MA — — — 4,062 — — 4,062 — 4,062 — N/A N/A N/A Fourth and Harrison Land San Francisco, CA — — — 3,936 — — 3,936 — 3,936 — N/A N/A N/A North First Master Plan Land San Jose, CA — — — 3,014 — — 3,014 — 3,014 — N/A 2007 N/A Broad Run Business Park Land Loudoun County, VA — — — 2,694 — — 2,694 — 2,694 — N/A 1998 N/A MacArthur Station Land Oakland, CA — — — 1,316 — — 1,316 — 1,316 — N/A N/A N/A 30 Shattuck Road Land Andover, MA — — — 1,214 — — 1,214 — 1,214 — N/A 1997 N/A 2100 Pennsylvania Avenue Land Washington, DC — — — 286 — — 286 — 286 — N/A N/A N/A $ 2,063,087 (2 ) $ 4,759,821 $ 11,416,957 $ 3,524,407 $ 4,774,460 $ 13,642,110 $ 246,656 (3 ) $ 1,037,959 $ 19,701,185 $ 4,116,020 Note: Total Real Estate does not include Furniture, Fixtures and Equipment totaling approximately $32,687 . Accumulated Depreciation does not include approximately $20,344 of accumulated depreciation related to Furniture, Fixtures and Equipment. The aggregate cost and accumulated depreciation for tax purposes was approximately $17.6 billion and $3.6 billion , respectively. (1) Depreciation of the buildings and improvements are calculated over lives ranging from the life of the lease to 40 years. (2) Includes the unamortized balance of the historical fair value adjustment and unamortized deferred financing costs totaling approximately $33.8 million and $(2.4) million , respectively. (3) Includes pre-development costs. Boston Properties Limited Partnership Real Estate and Accumulated Depreciation December 31, 2016 , 2015 and 2014 (dollars in thousands) A summary of activity for real estate and accumulated depreciation is as follows: 2016 2015 2014 Real Estate: Balance at the beginning of the year $ 19,031,289 $ 18,786,572 $ 18,523,277 Additions to/improvements of real estate 977,287 700,792 594,296 Assets sold/written-off (307,391 ) (456,075 ) (331,001 ) Balance at the end of the year $ 19,701,185 $ 19,031,289 $ 18,786,572 Accumulated Depreciation: Balance at the beginning of the year $ 3,826,862 $ 3,458,640 $ 3,081,040 Depreciation expense 548,397 478,457 447,667 Assets sold/written-off (259,239 ) (110,235 ) (70,067 ) Balance at the end of the year $ 4,116,020 $ 3,826,862 $ 3,458,640 Note: Real Estate and Accumulated Depreciation amounts do not include Furniture, Fixtures and Equipment.

Summary Of Significant Accoun30

Summary Of Significant Accounting Policies Summary Of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Accounting Policies [Abstract]
Real Estate	Real Estate Upon acquisitions of real estate that constitutes a business, which includes the consolidation of previously unconsolidated joint ventures, the Company assesses the fair value of acquired tangible and intangible assets (including land, buildings, tenant improvements, “above-” and “below-market” leases, leasing and assumed financing origination costs, acquired in-place leases, other identified intangible assets and assumed liabilities) and allocates the purchase price to the acquired assets and assumed liabilities, including land and buildings as if vacant. The Company assesses and considers fair value based on estimated cash flow projections that utilize discount and/or capitalization rates that it deems appropriate, as well as available market information. Estimates of future cash flows are based on a number of factors including the historical operating results, known and anticipated trends, and market and economic conditions. The fair value of the tangible assets of an acquired property considers the value of the property as if it were vacant. The Company also considers an allocation of purchase price of other acquired intangibles, including acquired in-place leases that may have a customer relationship intangible value, including (but not limited to) the nature and extent of the existing relationship with the tenants, the tenants’ credit quality and expectations of lease renewals. Based on its acquisitions to date, the Company’s allocation to customer relationship intangible assets has been immaterial. The Company records acquired “above-” and “below-market” leases at their fair values (using a discount rate which reflects the risks associated with the leases acquired) equal to the difference between (1) the contractual amounts to be paid pursuant to each in-place lease and (2) management’s estimate of fair market lease rates for each corresponding in-place lease, measured over a period equal to the remaining term of the lease for above-market leases and the initial term plus the term of any below-market fixed rate renewal options for below-market leases. Acquired “above-” and “below-market” lease values have been reflected within Prepaid Expenses and Other Assets and Other Liabilities, respectively, in the Company’s Consolidated Balance Sheets. Other intangible assets acquired include amounts for in-place lease values that are based on the Company’s evaluation of the specific characteristics of each tenant’s lease. Factors to be considered include estimates of carrying costs during hypothetical expected lease-up periods considering current market conditions, and costs to execute similar leases. In estimating carrying costs, the Company includes real estate taxes, insurance and other operating expenses and estimates of lost rentals at market rates during the expected lease-up periods, depending on local market conditions. In estimating costs to execute similar leases, the Company considers leasing commissions, legal and other related expenses. Management reviews its long-lived assets for impairment following the end of each quarter and when there is an event or change in circumstances that indicates an impairment in value. An impairment loss is recognized if the carrying amount of an asset is not recoverable and exceeds its fair value. The evaluation of anticipated cash flows is highly subjective and is based in part on assumptions regarding future occupancy, rental rates and capital requirements that could differ materially from actual results in future periods. Because cash flows on properties considered to be “long-lived assets to be held and used” are considered on an undiscounted basis to determine whether an asset has been impaired, the Company’s established strategy of holding properties over the long term directly decreases the likelihood of recording an impairment loss. If the Company’s strategy changes or market conditions otherwise dictate an earlier sale date, an impairment loss may be recognized and such loss could be material. If the Company determines that an impairment has occurred, the affected assets must be reduced to their fair value, less cost to sell. Guidance in Accounting Standards Codification (“ASC”) 360 “Property Plant and Equipment” (“ASC 360”) requires that qualifying assets and liabilities and the results of operations that have been sold, or otherwise qualify as “held for sale,” be presented as discontinued operations in all periods presented if the property operations are expected to be eliminated and the Company will not have significant continuing involvement following the sale. The components of the property’s net income that are reflected as discontinued operations include the net gain (or loss) upon the disposition of the property held for sale, operating results, depreciation and interest expense (if the property is subject to a secured loan). The Company generally considers assets to be “held for sale” when the transaction has been approved by Boston Properties, Inc.’s Board of Directors, or a committee thereof, and there are no known significant contingencies relating to the sale, such that a sale of the property within one year is considered probable. Following the classification of a property as “held for sale,” no further depreciation is recorded on the assets, and the asset is written down to the lower of carrying value or fair market value, less cost to sell. On April 10, 2014, the Financial Accounting Standards Board (“FASB”) issued ASU 2014-08, “Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity” (“ASU 2014-08”). ASU 2014-08 clarifies that discontinued operations presentation applies only to disposals representing a strategic shift that has (or will have) a major effect on an entity’s operations and financial results (e.g., a disposal of a major geographical area, a major line of business, a major equity method investment or other major parts of an entity). ASU 2014-08 is effective prospectively for reporting periods beginning after December 15, 2014. Early adoption is permitted, and the Company early adopted ASU 2014-08 during the first quarter of 2014. The Company’s adoption of ASU 2014-08 resulted in the operating results and gains on sales of real estate from operating properties sold during the years ended December 31, 2016, 2015 and 2014 not being reflected within Discontinued Operations in the Company’s Consolidated Statements of Operations (See Note 3 ). Real estate is stated at depreciated cost. A variety of costs are incurred in the acquisition, development and leasing of properties. The cost of buildings and improvements includes the purchase price of property, legal fees and other acquisition costs. The Company expenses costs that it incurs to effect a business combination such as legal, due diligence and other closing related costs. Costs directly related to the development of properties are capitalized. Capitalized development costs include interest, internal wages, property taxes, insurance, and other project costs incurred during the period of development. After the determination is made to capitalize a cost, it is allocated to the specific component of a project that is benefited. Determination of when a development project commences and capitalization begins, and when a development project is substantially complete and held available for occupancy and capitalization must cease, involves a degree of judgment. The Company’s capitalization policy on development properties is follows the guidance in ASC 835-20 “Capitalization of Interest” and ASC 970 “Real Estate-General.” The costs of land and buildings under development include specifically identifiable costs. The capitalized costs include pre-construction costs necessary to the development of the property, development costs, construction costs, interest costs, real estate taxes, salaries and related costs and other costs incurred during the period of development. The Company begins the capitalization of costs during the pre-construction period which it defines as activities that are necessary for the development of the property. The Company considers a construction project as substantially completed and held available for occupancy upon the completion of tenant improvements, but no later than one year from cessation of major construction activity. The Company ceases capitalization on the portion (1) substantially completed, (2) occupied or held available for occupancy, and capitalizes only those costs associated with the portion under construction or (3) if activities necessary for the development of the property have been suspended. Interest costs capitalized for the years ended December 31, 2016 , 2015 and 2014 were $39.2 million , $34.2 million and $52.5 million , respectively. Salaries and related costs capitalized for the years ended December 31, 2016 , 2015 and 2014 were $11.1 million , $10.4 million and $8.5 million , respectively. Expenditures for repairs and maintenance are charged to operations as incurred. Significant betterments are capitalized. When assets are sold or retired, their costs and related accumulated depreciation are removed from the accounts with the resulting gains or losses reflected in net income or loss for the period. The Company computes depreciation and amortization on properties using the straight-line method based on estimated useful asset lives. In accordance with ASC 805 “Business Combinations,” the Company allocates the acquisition cost of real estate to its components and depreciates or amortizes these assets (or liabilities) over their useful lives. The amortization of acquired “above-” and “below-market” leases and acquired in-place leases is recorded as an adjustment to revenue and depreciation and amortization, respectively, in the Consolidated Statements of Operations. Depreciation is computed on a straight-line basis over the estimated useful lives of the assets as follows: Land improvements 25 to 40 years Buildings and improvements 10 to 40 years Tenant improvements Shorter of useful life or terms of related lease Furniture, fixtures, and equipment 3 to 7 years
Cash and Cash Equivalents	Cash and Cash Equivalents Cash and cash equivalents consist of cash on hand and investments with maturities of three months or less from the date of purchase. The majority of the Company’s cash and cash equivalents are held at major commercial banks which may at times exceed the Federal Deposit Insurance Corporation limit of $250,000 . The Company has not experienced any losses to date on its invested cash.
Cash Held in Escrows	Cash Held in Escrows Escrows include amounts established pursuant to various agreements for security deposits, property taxes, insurance and other costs. Escrows also include cash held by qualified intermediaries for possible investments in like-kind exchanges in accordance with Section 1031 of the Internal Revenue Code in connection with sales of the Company’s properties.
Investments in Securities	Investments in Securities The Company accounts for investments in trading securities at fair value, with gains or losses resulting from changes in fair value recognized currently in earnings. The designation of trading securities is generally determined at acquisition. The Company maintains a deferred compensation plan that is designed to allow officers of Boston Properties, Inc. to defer a portion of their current income on a pre-tax basis and receive a tax-deferred return on these deferrals. The Company’s obligation under the plan is that of an unsecured promise to pay the deferred compensation to the plan participants in the future. At December 31, 2016 and 2015 , the Company had maintained approximately $23.8 million and $20.4 million , respectively, in a separate account, which is not restricted as to its use. The Company recognized gains (losses) of approximately $2.3 million , $(0.7) million and $1.0 million on its investments in the account associated with the Company’s deferred compensation plan during the years ended December 31, 2016 , 2015 and 2014 , respectively.
Tenant and Other Receivables	Tenant and Other Receivables Tenant and other accounts receivable, other than accrued rents receivable, are expected to be collected within one year.
Deferred Charges	Deferred Charges Deferred charges include leasing costs and financing fees. Leasing costs include acquired intangible in-place lease values and direct and incremental fees and costs incurred in the successful negotiation of leases, including brokerage, legal, internal leasing employee salaries and other costs which have been deferred and are being amortized on a straight-line basis over the terms of the respective leases. Internal leasing salaries and related costs capitalized for the years ended December 31, 2016 , 2015 and 2014 were $7.2 million , $5.5 million and $6.0 million , respectively. External fees and costs incurred to obtain long-term financing have been deferred and are being amortized over the terms of the respective loans and are included within interest expense. Unamortized financing and leasing costs are charged to expense upon the early repayment or significant modification of the financing or upon the early termination of the lease, respectively. Fully amortized deferred charges are removed from the books upon the expiration of the lease or maturity of the debt. On January 1, 2016, the Company adopted ASU 2015-03 “Interest - Imputation of Interst (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs” and retrospectively applied the guidance to its Mortgage Notes Payable and Unsecured Senior Notes for all periods presented (See Note 4 ). Unamortized deferred financing costs, which were previously included in Deferred Charges, Net, totaling approximately $2.4 million and $35.3 million are included in Mortgage Notes Payable, Net and Unsecured Senior Notes, Net, respectively, as of December 31, 2016 and approximately $3.5 million and $24.5 million are included in Mortgage Notes Payable, Net and Unsecured Senior Notes, Net, respectively, as of December 31, 2015. Net unamortized deferred financing costs associated with the Company’s Unsecured Line of Credit totaling approximately $1.9 million and $3.1 million as of December 31, 2016 and 2015, respectively, continue to be presented within Deferred Charges, Net as there is no balance outstanding.
Investments in Unconsolidated Joint Ventures	Investments in Unconsolidated Joint Ventures The Company consolidates VIEs in which it is considered to be the primary beneficiary. VIEs are entities in which the equity investors do not have sufficient equity at risk to finance their endeavors without additional financial support or that the holders of the equity investment at risk do not have substantive participating rights. The primary beneficiary 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 variable interest entity’s performance, and (2) the obligation to absorb losses and the right to receive the returns from the variable interest entity that could potentially be significant to the VIE. For ventures that are not VIEs, the Company consolidates entities for which it has significant decision making control over the ventures’ operations. The Company’s judgment with respect to its level of influence or control of an entity involves the consideration of various factors including the form of the Company’s ownership interest, its representation in the entity’s governance, the size of its investment (including loans), estimates of future cash flows, its ability to participate in policy making decisions and the rights of the other investors to participate in the decision making process and to replace the Company as manager and/or liquidate the venture, if applicable. The Company’s assessment of its influence or control over an entity affects the presentation of these investments in the Company’s consolidated financial statements. In addition to evaluating control rights, the Company consolidates entities in which the outside partner has no substantive kick-out rights to remove the Company as the managing member. Accounts of the consolidated entity are included in the accounts of the Company and the noncontrolling interest is reflected on the Consolidated Balance Sheets as a component of equity or in temporary equity between liabilities and equity. Investments in unconsolidated joint ventures are recorded initially at cost, and subsequently adjusted for equity in earnings and cash contributions and distributions. Any difference between the carrying amount of these investments on the balance sheet and the underlying equity in net assets is amortized as an adjustment to equity in earnings of unconsolidated joint ventures over the life of the related asset. Under the equity method of accounting, the net equity investment of the Company is reflected within the Consolidated Balance Sheets, and the Company’s share of net income or loss from the joint ventures is included within the Consolidated Statements of Operations. The joint venture agreements may designate different percentage allocations among investors for profits and losses; however, the Company’s recognition of joint venture income or loss generally follows the joint venture’s distribution priorities, which may change upon the achievement of certain investment return thresholds. The Company may account for cash distributions in excess of its investment in an unconsolidated joint venture as income when the Company is not the general partner in a limited partnership and when the Company has neither the requirement nor the intent to provide financial support to the joint venture. The Company’s investments in unconsolidated joint ventures are reviewed for impairment periodically and the Company records impairment charges when events or circumstances change indicating that a decline in the fair values below the carrying values has occurred and such decline is other-than-temporary. The ultimate realization of the investment in unconsolidated joint ventures is dependent on a number of factors, including the performance of each investment and market conditions. The Company will record an impairment charge if it determines that a decline in the value below the carrying value of an investment in an unconsolidated joint venture is other-than-temporary. To the extent that the Company contributes assets to a joint venture, the Company’s investment in the joint venture is recorded at the Company’s cost basis in the assets that were contributed to the joint venture. To the extent that the Company’s cost basis is different than the basis reflected at the joint venture level, the basis difference is amortized over the life of the related asset and included in the Company’s share of equity in net income of the joint venture. In accordance with the provisions of ASC 970-323 “Investments—Equity Method and Joint Ventures” (“ASC 970-323”), the Company will recognize gains on the contribution of real estate to joint ventures, relating solely to the outside partner’s interest, to the extent the economic substance of the transaction is a sale. The combined summarized financial information of the unconsolidated joint ventures is disclosed in Note 5 .
Revenue Recognition	Revenue Recognition In general, the Company commences rental revenue recognition when the tenant takes possession of the leased space and the leased space is substantially ready for its intended use. Contractual rental revenue is reported on a straight-line basis over the terms of the respective leases. The impact of the straight-line rent adjustment increased revenue by approximately $31.7 million , $80.0 million and $63.1 million for the years ended December 31, 2016 , 2015 and 2014 , respectively, as the revenue recorded exceeded amounts billed. Accrued rental income, as reported on the Consolidated Balance Sheets, represents cumulative rental income earned in excess of rent payments received pursuant to the terms of the individual lease agreements. The Company maintains an allowance against accrued rental income for future potential tenant credit losses. The credit assessment is based on the estimated accrued rental income that is recoverable over the term of the lease. The Company also maintains an allowance for doubtful accounts for estimated losses resulting from the inability of tenants to make required rent payments. The computation of this allowance is based on the tenants’ payment history and current credit status, as well as certain industry or geographic specific credit considerations. If the Company’s estimates of collectability differ from the cash received, then the timing and amount of the Company’s reported revenue could be impacted. The credit risk is mitigated by the high quality of the Company’s existing tenant base, reviews of prospective tenants’ risk profiles prior to lease execution and consistent monitoring of the Company’s portfolio to identify potential problem tenants. In accordance with ASC 805, the Company recognizes acquired in-place “above-” and “below-market” leases at their fair values as rental revenue over the original term of the respective leases. The impact of the acquired in-place “above-” and “below-market” leases increased revenue by approximately $30.2 million , $35.9 million and $48.3 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. The following table summarizes the scheduled amortization of the Company’s acquired “above-” and “below-market” lease intangibles for each of the five succeeding years (in thousands). Acquired Above-Market Lease Intangibles Acquired Below-Market Lease Intangibles 2017 $ 11,697 $ 33,871 2018 8,609 32,156 2019 7,100 27,318 2020 5,394 10,736 2021 2,988 6,294 Recoveries from tenants, consisting of amounts due from tenants for common area maintenance, real estate taxes and other recoverable costs, are recognized as revenue in the period during which the expenses are incurred. Tenant reimbursements are recognized and presented in accordance with guidance in ASC 605-45 “Principal Agent Considerations” (“ASC 605-45”). ASC 605-45 requires that these reimbursements be recorded on a gross basis, as the Company is generally the primary obligor with respect to purchasing goods and services from third-party suppliers, has discretion in selecting the supplier and has credit risk. The Company also receives reimbursement of payroll and payroll related costs from third parties which the Company reflects on a net basis. The Company’s parking revenues are derived from leases, monthly parking and transient parking. The Company recognizes parking revenue as earned. The Company’s hotel revenue is derived from room rentals and other sources such as charges to guests for telephone service, movie and vending commissions, meeting and banquet room revenue and laundry services. Hotel revenue is recognized as earned. The Company receives management and development fees from third parties. Property management fees are recorded and earned based on a percentage of collected rents at the properties under management, and not on a straight-line basis, because such fees are contingent upon the collection of rents. The Company records development fees as earned depending on the risk associated with each project. The Company recognizes development fees earned from joint venture projects equal to its cost plus profit to the extent of the third party partners’ ownership interest. Gains on sales of real estate are recognized pursuant to the provisions included in ASC 360-20 “Real Estate Sales” (“ASC 360-20”). The specific timing of the sale is measured against various criteria in ASC 360-20 related to the terms of the transaction and any continuing involvement in the form of management or financial assistance associated with the properties. If the sales criteria for the full accrual method are not met, the Company defers some or all of the gain recognition and accounts for the continued operations of the property by applying the finance, leasing, profit sharing, deposit, installment or cost recovery methods, as appropriate, until the sales criteria are met.
Ground Leases	Ground Leases The Company has non-cancelable ground lease obligations with various initial term expiration dates through 2114 . The Company recognizes ground rent expense on a straight-line basis over the terms of the respective ground lease agreements. The future contractual minimum lease payments to be made by the Company as of December 31, 2016 , under non-cancelable ground leases which expire on various dates through 2114 , are as follows: Years Ending December 31, (in thousands) 2017 $ 12,554 2018 28,781 2019 17,868 2020 9,870 2021 9,492 Thereafter 585,209
Earnings Per Share and Earnings Per Common Unit	Earnings Per Share Basic earnings per share (“EPS”) is computed by dividing net income available to common shareholders, as adjusted for undistributed earnings (if any) of certain securities issued by Boston Properties Limited Partnership, by the weighted average number of shares of Common Stock outstanding during the year. Diluted EPS reflects the potential dilution that could occur from shares issuable in connection with awards under stock-based compensation plans, including upon the exercise of stock options, and securities of Boston Properties Limited Partnership that are exchangeable for Common Stock. Earnings Per Common Unit Basic earnings per common unit is computed by dividing net income available to common unitholders, as adjusted for undistributed earnings (if any) of certain securities issued by Boston Properties Limited Partnership, by the weighted average number of common units outstanding during the year. Diluted earnings per common unit reflects the potential dilution that could occur from units issuable in connection with awards under Boston Properties, Inc.’s stock-based compensation plans, including upon the exercise of stock options, and conversion of preferred units of Boston Properties Limited Partnership.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying values of cash and cash equivalents, marketable securities, escrows, receivables, accounts payable, accrued expenses and other assets and liabilities are reasonable estimates of their fair values because of the short maturities of these 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 ASC 820 "Fair Value Measurements and Disclosures", the accounting standards for Fair Value Measurements and Disclosures) 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 the accounting standards for Fair Value Measurements and Disclosures) if trading volumes are low. The Company determines the fair value of its mortgage notes payable using discounted cash flow analysis by discounting the spread between the future contractual interest payments and hypothetical future interest payments on 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 mortgage notes payable and mezzanine notes payable are categorized at a level 3 basis (as defined in the accounting standards for Fair Value Measurements and Disclosures) due to the fact that the Company considers the rates used in the valuation techniques to be unobservable inputs. 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 if the Company’s estimates do not prove to be accurate, and the Company’s estimated fair values for these instruments as of the end of the applicable reporting period are not necessarily indicative of estimated or actual fair values in future reporting periods. The following table presents the aggregate carrying value of the Company’s mortgage notes payable, net, mezzanine notes payable and unsecured senior notes, net and the Company’s corresponding estimate of fair value as of December 31, 2016 and December 31, 2015 (in thousands): December 31, 2016 December 31, 2015 Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Mortgage notes payable, net $ 2,063,087 $ 2,092,237 $ 3,435,242 $ 3,503,746 Mezzanine notes payable 307,093 308,344 308,482 306,103 Unsecured senior notes, net 7,245,953 7,428,077 5,264,819 5,547,738 Total $ 9,616,133 $ 9,828,658 $ 9,008,543 $ 9,357,587 The Company uses interest rate swap agreements to manage its interest rate risk. The valuation of these instruments is determined using widely accepted valuation techniques, including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves. To comply with the provisions of ASC 820, the Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. Although the Company has determined that the majority of the inputs used to value its derivatives fall within level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by the Company and its counterparties. However, as of December 31, 2016, the Company has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivatives. As a result, the Company has determined that its derivative valuations in their entirety are classified in level 2 of the fair value hierarchy.
Derivative Instruments and Hedging Activities	Derivative Instruments and Hedging Activities Derivative instruments and hedging activities require management to make judgments on the nature of its derivatives and their effectiveness as hedges. These judgments determine if the changes in fair value of the derivative instruments are reported in the Consolidated Statements of Operations as a component of net income or as a component of comprehensive income and as a component of equity on the Consolidated Balance Sheets. While management believes its judgments are reasonable, a change in a derivative’s effectiveness as a hedge could materially affect expenses, net income and equity. The Company accounts for the effective portion of changes in the fair value of a derivative in other comprehensive income (loss) and subsequently reclassifies the effective portion to earnings over the term that the hedged transaction affects earnings. The Company accounts for the ineffective portion of changes in the fair value of a derivative directly in earnings.
Stock-Based Employee Compensation Plans	Stock-Based Employee Compensation Plans At December 31, 2016 , the Company has a stock-based employee compensation plan. The Company accounts for the plan under the guidance in ASC 718 “Compensation – Stock Compensation” (“ASC 718”), which revised the fair value based method of accounting for share-based payment liabilities, forfeitures and modifications of stock-based awards and clarified previous guidance in several areas, including measuring fair value, classifying an award as equity or as a liability and attributing compensation cost to reporting periods.
Use of Estimatesin the Preperation of Financial Statements	Use of Estimates in the Preparation of Financial Statements The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. These estimates include such items as depreciation and allowances for doubtful accounts. Actual results could differ from those estimates.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606)” (“ASU 2014-09”). The objective of ASU 2014-09 is to establish a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers and will supersede most of the existing revenue recognition guidance, including industry-specific guidance. The core principle is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In applying ASU 2014-09, companies will perform a five-step analysis of transactions to determine when and how revenue is recognized. ASU 2014-09 applies to all contracts with customers except those that are within the scope of other topics in the FASB’s ASC. In August 2015, the FASB issued ASU 2015-14, "Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date" (“ASU 2015-14”), which delayed the effective date of ASU 2014-09 by one year making it effective for the first interim period within annual reporting periods beginning after December 15, 2017. Early adoption is permitted as of the original effective date. In May 2016, the FASB issued ASU No. 2016-12, “Revenue from Contracts with Customers (Topic 606): Narrow-Scope Improvements and Practical Expedients” (“ASU 2016-12”). ASU 2016-12 is intended to clarify and provide practical expedients for certain aspects of ASU 2014-09, which outlines a single comprehensive model for entities to use in accounting for revenues arising from contracts with customers and notes that lease contracts with customers are a scope exception. The Company may elect to adopt ASU 2016-12 as of the original effective date; however, adoption is required for annual reporting periods beginning after December 15, 2017. The Company has commenced the process of adopting ASU 2014-09 for reporting periods beginning after December 15, 2017, including forming a project team and compiling an inventory of the sources of revenue the Company expects will be impacted by the adoption of ASU 2014-09. The Company expects that executory costs and certain non-lease components of revenue from leases (upon the adoption of ASU 2016-02), tenant service revenue, development and management services revenue, parking revenue and gains on sales of real estate may be impacted by the adoption of ASU 2014-09, although the Company expects that the impact will be to the pattern of revenue recognition and not the total revenue recognized over time. The Company is in the process of evaluating the significance of the impact on the changes in the recognition pattern of its revenue and is still completing its assessment of the overall impact of adopting ASU 2014-09. In April 2015, the FASB issued ASU 2015-03, “Interest - Imputation of Interst (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs” (“ASU 2015-03”), which requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs is not affected. ASU 2015-03 was effective for financial statements issued for fiscal years beginning after December 15, 2015, and interim periods within those fiscal years and shall be applied on a retrospective basis, wherein the balance sheet of each individual period presented should be adjusted to reflect the period-specific effects of applying the new guidance. Early adoption is permitted for financial statements that have not been previously issued. On January 1, 2016, the Company adopted ASU 2015-03 and retrospectively applied the guidance to its Mortgage Notes Payable and Unsecured Senior Notes for all periods presented. Unamortized deferred financing costs, which were previously included in Deferred Charges, Net, totaling approximately $2.4 million and $35.3 million are included in Mortgage Notes Payable, Net and Unsecured Senior Notes, Net, respectively, as of December 31, 2016 and approximately $3.5 million and $24.5 million are included in Mortgage Notes Payable, Net and Unsecured Senior Notes, Net, respectively, as of December 31, 2015. In January 2016, the FASB issued ASU 2016-01, “Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities” (“ASU 2016-01”). ASU 2016-01 requires equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income, requires public business entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes, requires separate presentation of financial assets and financial liabilities by measurement category and form of financial asset, and eliminates the requirement for public business entities to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost. ASU 2016-01 is effective for the Company for reporting periods beginning after December 15, 2017. Early adoption is permitted. The adoption of ASU 2016-01 will not have a material impact on the Company’s consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, “ Leases (Topic 842) ” (“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 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 existing guidance for operating leases today. The new standard requires lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales-type leases, direct financing leases and operating leases. ASU 2016-02 supersedes previous leasing standards . ASU 2016-02 is effective for the Company for reporting periods beginning after December 15, 2018, with early adoption permitted. The Company has commenced the process of adopting ASU 2016-02 by forming a project team and beginning to compile an inventory of its leases that will be impacted by the adoption of ASU 2016-02. The Company is still assessing the impact of adopting ASU 2016-02. However, the Company expects that its operating leases where it is the lessor will be accounted for on its balance sheet similar to its current accounting with the underlying leased asset recognized as real estate. The Company expects that executory costs and certain other non-lease components will need to be accounted for separately from the lease component of the lease with the lease component continuing to be recognized on a straight-line basis over the lease term and the executory costs and certain other non-lease components being accounted for under the new revenue recognition guidance in ASU 2014-09. For leases in which the Company is the lessee, primarily consisting of ground leases, the Company expects to recognize a right-of-use asset and a lease liability equal to the present value of the minimum lease payments with rental payments being applied to the lease liability and to interest expense and the right-of-use asset being amortized to expense on a straight line basis over the term of the lease. In addition, under ASU 2016-02, lessors may only capitalize incremental direct leasing costs. As a result, the Company expects that it will no longer be able to capitalize its internal leasing wages and instead will expense these costs as incurred. In March 2016, the FASB issued ASU 2016-05, “Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships (a consensus of the FASB Emerging Issues Task Force)” (“ASU 2016-05”), which provides guidance clarifying that a novation of party to a derivative instrument, whereby one of the parties to a derivative instrument is replaced with another party, does not, in and of itself, require de-designation of that hedging relationship provided that all other hedge criteria continue to be met. ASU 2016-05 is effective for the Company for reporting periods beginning after December 15, 2016, with early adoption permitted. The adoption of ASU 2016-05 will not have a material impact on the Company’s consolidated financial statements. In March 2016, the FASB issued ASU 2016-09, “Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting” (“ASU 2016-09”) . ASU 2016-09 is intended to improve the accounting for share-based payments and affects all organizations that issue share-based payment awards to their employees. Several aspects of the accounting for share-based payment awards are simplified with ASU 2016-09, including income tax consequences, classification of awards as equity or liabilities and classification on the statement of cash flows. ASU 2016-09 is effective for the Company for reporting periods beginning after December 15, 2016, with early adoption permitted. The adoption of ASU 2016-09 will not have a material impact on the Company’s consolidated financial statements. In August 2016, the FASB issued ASU No. 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (a consensus of the FASB Emerging Issues Task Force)” (“ASU 2016-15”). ASU 2016-15 is intended to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. The areas addressed in the new guidance related to debt prepayment costs, settlement of zero-coupon debt instruments, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of corporate-owned and bank-owned life insurance policies, distributions received from equity method investments, beneficial interest in securitization transactions, and separately identifiable cash flows and application of the predominance principle. ASU 2016-15 is effective for the Company for reporting periods beginning after December 15, 2017, with early adoption permitted, provided that all of the amendments are adopted in the same period. The adoption of ASU 2016-15 will not have a material impact on the Company’s consolidated financial statements. In November 2016, the FASB issued ASU No. 2016-18, “Statement of Cash Flows (Topic 230): Restricted Cash (a consensus of the FASB Emerging Issues Task Force)” (“ASU 2016-18”). ASU 2016-18 will require companies to include restricted cash and restricted cash equivalents with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. ASU 2016-18 will require a disclosure of a reconciliation between the statement of financial position and the statement of cash flows when the statement of financial position includes more than one line item for cash, cash equivalents, restricted cash and restricted cash equivalents. Entities with material restricted cash and restricted cash equivalents balances will be required to disclose the nature of the restrictions. ASU 2016-18 is effective for reporting periods beginning after December 15, 2017, with early adoption permitted, and will be applied retrospectively to all periods presented. The adoption of ASU 2016-18 will not have a material impact on the Company’s consolidated financial statements. In January 2017, the FASB issued ASU 2017-01, “Business Combinations (Topic 805): Clarifying the Definition of a Business” (“ASU 2017-01”). ASU 2017-01 clarifies the framework for determining whether an integrated set of assets and activities meets the definition of a business. The revised framework establishes a screen for determining whether an integrated set of assets and activities is a business and narrows the definition of a business, which is expected to result in fewer transactions being accounted for as business combinations. Acquisitions of integrated sets of assets and activities that do not meet the definition of a business are accounted for as asset acquisitions. This update is effective for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2017, with early adoption permitted for transactions that have not been reported in previously issued (or available to be issued) financial statements and shall be applied on a prospective basis. The Company early adopted ASU 2017-01 during the first quarter of 2017. The Company expects that acquisitions of real estate or in-substance real estate will not meet the revised definition of a business because substantially all of the fair value is concentrated in a single identifiable asset or group of similar identifiable assets (i.e. land, buildings, and related intangible assets) or because the acquisition does not include a substantive process in the form of an acquired workforce or an acquired contract that cannot be replaced without significant cost, effort or delay.
Equity Offering Costs	Equity Offering Costs Underwriting commissions and offering costs have been reflected as a reduction of additional paid-in capital
Treasury Stock	Treasury Stock Boston Properties, Inc.’s share repurchases are reflected as treasury stock utilizing the cost method of accounting and are presented as a reduction to consolidated stockholders’ equity.
Dividends	Dividends Earnings and profits, which determine the taxability of dividends to stockholders, will differ from income reported for financial reporting purposes due to the differences for federal income tax purposes in the treatment of gains/losses on the sale of real property, revenue and expense recognition, compensation expense, and in the estimated useful lives and basis used to compute depreciation. The tax treatment of common dividends per share for federal income tax purposes is as follows: For the year ended December 31, 2016 2015 2014 Per Share % Per Share % Per Share % Ordinary income $ 2.76 90.51 % $ 2.34 57.97 % $ — — % Capital gain income 0.29 9.49 % 1.70 42.03 % 6.82 100.00 % Total $ 3.05 (1) 100.00 % $ 4.04 (2) 100.00 % $ 6.82 (3) 100.00 % _____________ (1) The fourth quarter 2016 regular quarterly dividend was $0.75 per common share of which approximately $0.56 per common share was allocable to 2016 and approximately $0.19 per common share is allocable to 2017. (2) The fourth quarter 2015 dividend of $1.90 per common share consists of a $1.25 per common share special dividend and a $0.65 per common share regular quarterly dividend. Approximately $1.35 per common share was allocable to 2015 and approximately $0.55 per common share is allocable to 2016. (3) The fourth quarter 2014 dividend of $5.15 per common share consists of a $4.50 per common share special dividend and a $0.65 per common share regular quarterly dividend. Approximately $4.41 per common share was allocable to 2014 and approximately $0.74 per common share is allocable to 2015.
Income Taxes	Income Taxes Boston Properties, Inc. has elected to be treated as a REIT under Sections 856 through 860 of the Internal Revenue Code of 1986, as amended (the “Code”), commencing with its taxable year ended December 31, 1997. As a result, it generally will not be subject to federal corporate income tax on its taxable income that is distributed to its stockholders. A REIT is subject to a number of organizational and operational requirements, including a requirement that it currently distribute at least 90% of its annual taxable income (with certain adjustments). Boston Properties, Inc.’s policy is to distribute at least 100% of its taxable income. Accordingly, the only provision for federal income taxes in the accompanying consolidated financial statements relates to Boston Properties, Inc.’s consolidated taxable REIT subsidiaries. Boston Properties, Inc.’s taxable REIT subsidiaries did not have significant tax provisions or deferred income tax items. Boston Properties, Inc. has no uncertain tax positions recognized as of December 31, 2016 and 2015 . The Company owns a hotel property which is managed through a taxable REIT subsidiary. The hotel taxable REIT subsidiary, a wholly owned subsidiary of Boston Properties Limited Partnership, is the lessee pursuant to the lease for the hotel property. As lessor, Boston Properties Limited Partnership is entitled to a percentage of gross receipts from the hotel property. Marriott International, Inc. continues to manage the hotel property under the Marriott name and under terms of the existing management agreement. The hotel taxable REIT subsidiary is subject to tax at the federal and state level and, accordingly, Boston Properties, Inc. has recorded a tax provision in its Consolidated Statements of Operations for the years ended December 31, 2016 , 2015 and 2014 . The net difference between the tax basis and the reported amounts of Boston Properties, Inc.’s assets and liabilities is approximately $1.7 billion and $1.6 billion as of December 31, 2016 and 2015 , respectively, which is primarily related to the difference in basis of contributed property and accrued rental income. Certain entities included in Boston Properties, Inc.’s consolidated financial statements are subject to certain state and local taxes. These taxes are recorded as operating expenses in the accompanying consolidated financial statements. The following table reconciles GAAP net income attributable to Boston Properties, Inc. to taxable income (unaudited): For the year ended December 31, 2016 2015 2014 (in thousands) Net income attributable to Boston Properties, Inc. $ 512,785 $ 583,106 $ 443,611 Straight-line rent and net “above-” and “below-market” rent adjustments (65,861 ) (92,483 ) (91,733 ) Book/Tax differences from depreciation and amortization 235,819 307,115 239,681 Book/Tax differences from interest expense (36,223 ) (43,349 ) (43,148 ) Book/Tax differences on gains/(losses) from capital transactions (70,880 ) (74,482 ) 943,778 (1) Book/Tax differences from stock-based compensation 33,463 22,008 32,483 Tangible Property Regulations (2) (104,783 ) (74,887 ) (442,650 ) Other book/tax differences, net (6,121 ) (15,259 ) (7,945 ) Taxable income $ 498,199 $ 611,769 $ 1,074,077 __________ (1) Consists primarily of the gain on sale of real estate for tax purposes related to the October 2014 sale by the Company of a 45% interest in each of 601 Lexington Avenue in New York City and Atlantic Wharf Office Building and 100 Federal Street in Boston, which was accounted for as an equity transaction for GAAP purposes with no gain on sale of real estate recognized. (2) In September 2013, the Internal Revenue Service released final Regulations governing when taxpayers like Boston Properties, Inc. must capitalize and depreciate costs for acquiring, maintaining, repairing and replacing tangible property and when taxpayers can deduct such costs. These final Regulations were effective for tax years beginning on or after January 1, 2014. These Regulations permitted Boston Properties, Inc. to deduct certain types of expenditures that were previously required to be capitalized. The Regulations also allowed Boston Properties, Inc. to make a one -time election in 2014 to immediately deduct certain amounts that were capitalized in previous years that are not required to be capitalized under the new Regulations. The one -time deduction included above totaled approximately $385.6 million for the year ended December 31, 2014. Boston Properties Limited Partnership Income Taxes The partners are required to report their respective share of Boston Properties Limited Partnership’s taxable income or loss on their respective tax returns and are liable for any related taxes thereon. Accordingly, the only provision for federal income taxes in the accompanying consolidated financial statements relates to Boston Properties Limited Partnership’s consolidated taxable REIT subsidiaries. Boston Properties Limited Partnership’s taxable REIT subsidiaries did not have significant tax provisions or deferred income tax items. Boston Properties Limited Partnership has no uncertain tax positions recognized as of December 31, 2016 and 2015 . The Company owns a hotel property which is managed through a taxable REIT subsidiary. The hotel taxable REIT subsidiary, a wholly owned subsidiary Boston Properties Limited Partnership, is the lessee pursuant to the lease for the hotel property. As lessor, Boston Properties Limited Partnership is entitled to a percentage of gross receipts from the hotel property. Marriott International, Inc. continues to manage the hotel property under the Marriott name and under terms of the existing management agreement. The hotel taxable REIT subsidiary is subject to tax at the federal and state level and, accordingly, Boston Properties Limited Partnership has recorded a tax provision in its Consolidated Statements of Operations for the years ended December 31, 2016 , 2015 and 2014 . The net difference between the tax basis and the reported amounts of Boston Properties Limited Partnership’s assets and liabilities is approximately $2.7 billion and $2.6 billion as of December 31, 2016 and 2015 , respectively, which is primarily related to the difference in basis of contributed property and accrued rental income. Certain entities included in Boston Properties Limited Partnership’s consolidated financial statements are subject to certain state and local taxes. These taxes are recorded as operating expenses in the accompanying consolidated financial statements. The following table reconciles GAAP net income attributable to Boston Properties Limited Partnership to taxable income (unaudited): For the year ended December 31, 2016 2015 2014 (in thousands) Net income attributable to Boston Properties Limited Partnership $ 585,841 $ 659,248 $ 509,629 Straight-line rent and net “above-” and “below-market” rent adjustments (73,604 ) (103,227 ) (102,319 ) Book/Tax differences from depreciation and amortization 245,239 329,629 253,590 Book/Tax differences from interest expense (40,481 ) (48,385 ) (48,128 ) Book/Tax differences on gains/(losses) from capital transactions (69,683 ) (67,602 ) 1,065,518 (1) Book/Tax differences from stock-based compensation 37,397 24,565 36,232 Tangible Property Regulations (2) (117,102 ) (83,587 ) (493,731 ) Other book/tax differences, net (3,387 ) (14,561 ) (11,403 ) Taxable income $ 564,220 $ 696,080 $ 1,209,388 __________ (1) Consists primarily of the gain on sale of real estate for tax purposes related to the October 2014 sale by the Company of a 45% interest in each of 601 Lexington Avenue in New York City and Atlantic Wharf Office Building and 100 Federal Street in Boston, which was accounted for as an equity transaction for GAAP purposes with no gain on sale of real estate recognized. (2) In September 2013, the Internal Revenue Service released final Regulations governing when taxpayers like Boston Properties Limited Partnership must capitalize and depreciate costs for acquiring, maintaining, repairing and replacing tangible property and when taxpayers can deduct such costs. These final Regulations were effective for tax years beginning on or after January 1, 2014. These Regulations permitted Boston Properties Limited Partnership to deduct certain types of expenditures that were previously required to be capitalized. The Regulations also allowed Boston Properties Limited Partnership to make a one -time election in 2014 to immediately deduct certain amounts that were capitalized in previous years that are not required to be capitalized under the new Regulations. The one -time deduction included above totaled approximately $430.1 million for the year ended December 31, 2014.

Summary Of Significant Accoun31

Summary Of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Property, Plant and Equipment [Table Text Block]	Depreciation is computed on a straight-line basis over the estimated useful lives of the assets as follows: Land improvements 25 to 40 years Buildings and improvements 10 to 40 years Tenant improvements Shorter of useful life or terms of related lease Furniture, fixtures, and equipment 3 to 7 years
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	The following table summarizes the scheduled amortization of the Company’s acquired “above-” and “below-market” lease intangibles for each of the five succeeding years (in thousands). Acquired Above-Market Lease Intangibles Acquired Below-Market Lease Intangibles 2017 $ 11,697 $ 33,871 2018 8,609 32,156 2019 7,100 27,318 2020 5,394 10,736 2021 2,988 6,294 The following table summarizes the scheduled amortization of the Company’s acquired in-place lease intangibles for each of the five succeeding years (in thousands). Acquired In-Place Lease Intangibles 2017 $ 37,547 2018 32,831 2019 26,556 2020 13,885 2021 8,365
Schedule Of Future Contractual Minimum Lease Payments Under Non-Cancelable Ground Leases [Table Text Block]	The future contractual minimum lease payments to be made by the Company as of December 31, 2016 , under non-cancelable ground leases which expire on various dates through 2114 , are as follows: Years Ending December 31, (in thousands) 2017 $ 12,554 2018 28,781 2019 17,868 2020 9,870 2021 9,492 Thereafter 585,209
Fair Value, by Balance Sheet Grouping [Table Text Block]	The following table presents the aggregate carrying value of the Company’s mortgage notes payable, net, mezzanine notes payable and unsecured senior notes, net and the Company’s corresponding estimate of fair value as of December 31, 2016 and December 31, 2015 (in thousands): December 31, 2016 December 31, 2015 Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Mortgage notes payable, net $ 2,063,087 $ 2,092,237 $ 3,435,242 $ 3,503,746 Mezzanine notes payable 307,093 308,344 308,482 306,103 Unsecured senior notes, net 7,245,953 7,428,077 5,264,819 5,547,738 Total $ 9,616,133 $ 9,828,658 $ 9,008,543 $ 9,357,587
Tax Treatment Of Common Dividends Per Share For Federal Tax Purposes, Table [Table Text Block]	The tax treatment of common dividends per share for federal income tax purposes is as follows: For the year ended December 31, 2016 2015 2014 Per Share % Per Share % Per Share % Ordinary income $ 2.76 90.51 % $ 2.34 57.97 % $ — — % Capital gain income 0.29 9.49 % 1.70 42.03 % 6.82 100.00 % Total $ 3.05 (1) 100.00 % $ 4.04 (2) 100.00 % $ 6.82 (3) 100.00 % _____________ (1) The fourth quarter 2016 regular quarterly dividend was $0.75 per common share of which approximately $0.56 per common share was allocable to 2016 and approximately $0.19 per common share is allocable to 2017. (2) The fourth quarter 2015 dividend of $1.90 per common share consists of a $1.25 per common share special dividend and a $0.65 per common share regular quarterly dividend. Approximately $1.35 per common share was allocable to 2015 and approximately $0.55 per common share is allocable to 2016. (3) The fourth quarter 2014 dividend of $5.15 per common share consists of a $4.50 per common share special dividend and a $0.65 per common share regular quarterly dividend. Approximately $4.41 per common share was allocable to 2014 and approximately $0.74 per common share is allocable to 2015.
Gaap Reconciliation Of Net Income To Taxable Income, Table [Table Text Block]	The following table reconciles GAAP net income attributable to Boston Properties, Inc. to taxable income (unaudited): For the year ended December 31, 2016 2015 2014 (in thousands) Net income attributable to Boston Properties, Inc. $ 512,785 $ 583,106 $ 443,611 Straight-line rent and net “above-” and “below-market” rent adjustments (65,861 ) (92,483 ) (91,733 ) Book/Tax differences from depreciation and amortization 235,819 307,115 239,681 Book/Tax differences from interest expense (36,223 ) (43,349 ) (43,148 ) Book/Tax differences on gains/(losses) from capital transactions (70,880 ) (74,482 ) 943,778 (1) Book/Tax differences from stock-based compensation 33,463 22,008 32,483 Tangible Property Regulations (2) (104,783 ) (74,887 ) (442,650 ) Other book/tax differences, net (6,121 ) (15,259 ) (7,945 ) Taxable income $ 498,199 $ 611,769 $ 1,074,077 __________ (1) Consists primarily of the gain on sale of real estate for tax purposes related to the October 2014 sale by the Company of a 45% interest in each of 601 Lexington Avenue in New York City and Atlantic Wharf Office Building and 100 Federal Street in Boston, which was accounted for as an equity transaction for GAAP purposes with no gain on sale of real estate recognized. (2) In September 2013, the Internal Revenue Service released final Regulations governing when taxpayers like Boston Properties, Inc. must capitalize and depreciate costs for acquiring, maintaining, repairing and replacing tangible property and when taxpayers can deduct such costs. These final Regulations were effective for tax years beginning on or after January 1, 2014. These Regulations permitted Boston Properties, Inc. to deduct certain types of expenditures that were previously required to be capitalized. The Regulations also allowed Boston Properties, Inc. to make a one -time election in 2014 to immediately deduct certain amounts that were capitalized in previous years that are not required to be capitalized under the new Regulations. The one -time deduction included above totaled approximately $385.6 million for the year ended December 31, 2014.
Boston Properties Limited Partnership
Summary Of Significant Accounting Policies [Line Items]
Gaap Reconciliation Of Net Income To Taxable Income, Table [Table Text Block]	The following table reconciles GAAP net income attributable to Boston Properties Limited Partnership to taxable income (unaudited): For the year ended December 31, 2016 2015 2014 (in thousands) Net income attributable to Boston Properties Limited Partnership $ 585,841 $ 659,248 $ 509,629 Straight-line rent and net “above-” and “below-market” rent adjustments (73,604 ) (103,227 ) (102,319 ) Book/Tax differences from depreciation and amortization 245,239 329,629 253,590 Book/Tax differences from interest expense (40,481 ) (48,385 ) (48,128 ) Book/Tax differences on gains/(losses) from capital transactions (69,683 ) (67,602 ) 1,065,518 (1) Book/Tax differences from stock-based compensation 37,397 24,565 36,232 Tangible Property Regulations (2) (117,102 ) (83,587 ) (493,731 ) Other book/tax differences, net (3,387 ) (14,561 ) (11,403 ) Taxable income $ 564,220 $ 696,080 $ 1,209,388 __________ (1) Consists primarily of the gain on sale of real estate for tax purposes related to the October 2014 sale by the Company of a 45% interest in each of 601 Lexington Avenue in New York City and Atlantic Wharf Office Building and 100 Federal Street in Boston, which was accounted for as an equity transaction for GAAP purposes with no gain on sale of real estate recognized. (2) In September 2013, the Internal Revenue Service released final Regulations governing when taxpayers like Boston Properties Limited Partnership must capitalize and depreciate costs for acquiring, maintaining, repairing and replacing tangible property and when taxpayers can deduct such costs. These final Regulations were effective for tax years beginning on or after January 1, 2014. These Regulations permitted Boston Properties Limited Partnership to deduct certain types of expenditures that were previously required to be capitalized. The Regulations also allowed Boston Properties Limited Partnership to make a one -time election in 2014 to immediately deduct certain amounts that were capitalized in previous years that are not required to be capitalized under the new Regulations. The one -time deduction included above totaled approximately $430.1 million for the year ended December 31, 2014.

Real Estate (Tables)

Real Estate (Tables)	12 Months Ended
	Dec. 31, 2016
Real Estate Properties [Line Items]
Schedule of Property Subject to or Available for Operating Lease	Boston Properties, Inc. Real estate consisted of the following at December 31 (in thousands): 2016 2015 Land $ 4,879,020 $ 4,806,021 Land held for future development (1) 246,656 252,195 Buildings and improvements 11,890,626 11,709,285 Tenant improvements 2,060,315 1,920,247 Furniture, fixtures and equipment 32,687 29,852 Construction in progress 1,037,959 763,935 Total 20,147,263 19,481,535 Less: Accumulated depreciation (4,222,235 ) (3,925,894 ) $ 15,925,028 $ 15,555,641 _______________ (1) Includes pre-development costs. Boston Properties Limited Partnership Real estate consisted of the following at December 31 (in thousands): 2016 2015 Land $ 4,774,460 $ 4,700,793 Land held for future development (1) 246,656 252,195 Buildings and improvements 11,581,795 11,394,119 Tenant improvements 2,060,315 1,920,247 Furniture, fixtures and equipment 32,687 29,852 Construction in progress 1,037,959 763,935 Total 19,733,872 19,061,141 Less: Accumulated depreciation (4,136,364 ) (3,846,816 ) $ 15,597,508 $ 15,214,325 _______________ (1) Includes pre-development costs.
3625-3635 Peterson Way
Real Estate Properties [Line Items]
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	The following table summarizes the allocation of the aggregate purchase price of 3625-3635 Peterson Way at the date of acquisition (in thousands). Land $ 63,206 Building and improvements 7,210 Tenant improvements 7,669 In-place lease intangibles 4,262 Below-market lease intangible (4,347 ) Net assets acquired $ 78,000
Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block]	The following table summarizes the estimated annual amortization of the acquired below-market lease intangible and the acquired in-place lease intangibles for 3625-3635 Peterson Way for the remainder of 2016 and each of the next four succeeding fiscal years (in thousands). Acquired In-Place Lease Intangibles Acquired Below- Market Lease Intangible Period from April 22, 2016 through December 31, 2016 $ 296 $ (589 ) 2017 444 (884 ) 2018 444 (884 ) 2019 444 (884 ) 2020 444 (884 )

Deferred Charges (Tables)

Deferred Charges (Tables)	12 Months Ended
	Dec. 31, 2016
Deferred Charges [Abstract]
Deferred Charges	Deferred charges consisted of the following at December 31 (in thousands): 2016 2015 Leasing costs, including lease related intangibles $ 1,132,092 $ 1,123,105 Financing costs 6,094 6,094 1,138,186 1,129,199 Less: Accumulated amortization (452,023 ) (424,332 ) $ 686,163 $ 704,867
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	The following table summarizes the scheduled amortization of the Company’s acquired “above-” and “below-market” lease intangibles for each of the five succeeding years (in thousands). Acquired Above-Market Lease Intangibles Acquired Below-Market Lease Intangibles 2017 $ 11,697 $ 33,871 2018 8,609 32,156 2019 7,100 27,318 2020 5,394 10,736 2021 2,988 6,294 The following table summarizes the scheduled amortization of the Company’s acquired in-place lease intangibles for each of the five succeeding years (in thousands). Acquired In-Place Lease Intangibles 2017 $ 37,547 2018 32,831 2019 26,556 2020 13,885 2021 8,365

Investments in Unconsolidated34

Investments in Unconsolidated Joint Ventures (Tables)	12 Months Ended
	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Investments In Unconsolidated Joint Ventures	The investments in unconsolidated joint ventures consist of the following at December 31, 2016 and 2015: Carrying Value of Investment (1) Entity Properties Nominal % Ownership December 31, December 31, (in thousands) Square 407 Limited Partnership Market Square North 50.0 % $ (8,134 ) $ (9,951 ) BP/CRF Metropolitan Square LLC Metropolitan Square 20.0 % (2) 2,004 9,179 901 New York LLC 901 New York Avenue 25.0 % (3) (10,564 ) (11,958 ) WP Project Developer LLC Wisconsin Place Land and Infrastructure 33.3 % (4) 41,605 43,524 Annapolis Junction NFM, LLC Annapolis Junction 50.0 % (5) 20,539 29,009 540 Madison Venture LLC 540 Madison Avenue 60.0 % 67,816 68,983 500 North Capitol LLC 500 North Capitol Street, NW 30.0 % (3,389 ) (3,292 ) 501 K Street LLC 1001 6th Street 50.0 % (6) 42,528 42,584 Podium Developer LLC The Hub on Causeway - Podium 50.0 % 29,869 18,508 Residential Tower Developer LLC The Hub on Causeway - Residential 50.0 % 20,803 N/A Hotel Tower Developer LLC The Hub on Causeway - Hotel 50.0 % 933 N/A 1265 Main Office JV LLC 1265 Main Street 50.0 % 4,779 11,916 BNY Tower Holdings LLC Dock 72 at the Brooklyn Navy Yard 50.0 % (7) 33,699 11,521 CA-Colorado Center Limited Partnership Colorado Center 49.8 % 510,623 N/A $ 753,111 $ 210,023 _______________ (1) Investments with deficit balances aggregating approximately $22.1 million and $25.2 million at December 31, 2016 and 2015, respectively, have been reflected within Other Liabilities in the Company’s Consolidated Balance Sheets. (2) On October 20, 2016, the Company sold a 31% ownership interest in this joint venture. (3) The Company’s economic ownership has increased based on the achievement of certain return thresholds. (4) The Company’s wholly-owned entity that owns the office component of the project also owns a 33.3% interest in the entity owning the land, parking garage and infrastructure of the project. (5) The joint venture owns four in-service buildings and two undeveloped land parcels. (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: December 31, December 31, (in thousands) ASSETS Real estate and development in process, net $ 1,519,217 $ 1,072,412 Other assets 297,263 252,285 Total assets $ 1,816,480 $ 1,324,697 LIABILITIES AND MEMBERS’/PARTNERS’ EQUITY Mortgage and notes payable, net $ 865,665 $ 830,125 Other liabilities 67,167 44,549 Members’/Partners’ equity 883,648 450,023 Total liabilities and members’/partners’ equity $ 1,816,480 $ 1,324,697 Company’s share of equity $ 450,662 $ 237,070 Basis differentials (1) 302,449 (27,047 ) Carrying value of the Company’s investments in unconsolidated joint ventures (2) $ 753,111 $ 210,023 _______________ (1) 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 December 31, 2016, there is an aggregate basis differential of approximately $328.8 million 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. (2) Investments with deficit balances aggregating approximately $22.1 million and $25.2 million at December 31, 2016 and 2015 , 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: For the year ended December 31, 2016 2015 2014 (in thousands) Total revenue (1) $ 177,182 $ 155,642 $ 158,161 Expenses Operating 76,741 65,093 62,974 Depreciation and amortization 44,989 36,057 37,041 Total expenses 121,730 101,150 100,015 Operating income 55,452 54,492 58,146 Other income (expense) Interest expense (34,016 ) (32,176 ) (31,896 ) Net income $ 21,436 $ 22,316 $ 26,250 Company’s share of net income (2) $ 9,873 $ 22,031 $ 11,913 Basis differential (3) (1,799 ) 739 856 Income from unconsolidated joint ventures $ 8,074 $ 22,770 $ 12,769 Gain on sale of investment in unconsolidated joint venture $ 59,370 $ — $ — _______________ (1) Includes straight-line rent adjustments of approximately $18.1 million , $3.9 million and $3.0 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. (2) During the year ended December 31, 2015, the Company received a distribution of approximately $24.5 million , which was generated from the excess loan proceeds from the refinancing of 901 New York Avenue’s mortgage loan to a new 10 -year mortgage loan totaling $225.0 million . The Company’s allocation of income and distributions for the year ended December 31, 2015 was not proportionate to its nominal ownership interest as a result of the achievement of specified investment return thresholds, as provided for in the joint venture agreement. (3) Includes the Company’s share of straight-line rent adjustments of approximately $1.4 million and net below-market rent adjustments of approximately $0.9 million for the year ended December 31, 2016.
Colorado Center [Member]
Schedule of Equity Method Investments [Line Items]
Schedule of Business Acquisitions, by Acquisition [Table Text Block]	Land and improvements $ 189,597 Site improvements 9,050 Building and improvements 259,592 Tenant improvements 17,234 In-place lease intangibles 43,157 Above-market lease intangible 819 Below-market lease intangible (16,461 ) Net assets $ 502,988

Mortgage Notes Payable Schedule

Mortgage Notes Payable Schedule of Aggregate Principal Payments On Mortgage Notes (Tables)	12 Months Ended
	Dec. 31, 2016
Mortgage Notes Payable [Abstract]
Schedule of Aggregate Principal Payments On Mortgage Notes [Table Text Block]	Contractual aggregate principal payments of mortgage notes payable at December 31, 2016 are as follows: Principal Payments (in thousands) 2017 $ 1,317,654 2018 18,633 2019 19,670 2020 20,766 2021 40,182 Thereafter 614,710 Total aggregate principal payments 2,031,615 Unamortized balance of historical fair value adjustment 33,830 Deferred financing costs, net (2,358 ) Total carrying value of mortgage notes payable, net $ 2,063,087

Derivative and Hedging Instru36

Derivative and Hedging Instruments Derivatives and Hedging Activities Notional Table (Tables)	12 Months Ended
	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block]	767 Fifth Avenue Partners LLC’s interest rate swap contracts consisted of the following at December 31, 2016 (dollars in thousands): Derivative Instrument Aggregate Notional Amount Effective Date Maturity Date Strike Rate Range Balance Sheet Location Fair Value Low High 767 Fifth Partners LLC: Interest Rate Swaps $ 350,000 June 7, 2017 June 7, 2027 2.418 % - 2.950 % Other Liabilities $ (8,773 ) Interest Rate Swaps 100,000 June 7, 2017 June 7, 2027 2.336 % - 2.388 % Prepaid Expenses and Other Assets 509 $ 450,000 $ (8,264 ) Boston Properties Limited Partnership’s and 767 Fifth Avenue Partners LLC’s interest rate swap contracts consisted of the following at December 31, 2015 (dollars in thousands): Derivative Instrument Aggregate Notional Amount Effective Date Maturity Date Strike Rate Range Balance Sheet Location Fair Value Low High Boston Properties Limited Partnership: Interest Rate Swaps $ 400,000 September 1, 2016 September 1, 2026 2.348 % - 2.571 % Other Liabilities $ (5,419 ) Interest Rate Swaps 150,000 September 1, 2016 September 1, 2026 2.129 % - 2.325 % Prepaid Expenses and Other Assets 1,188 $ 550,000 $ (4,231 ) 767 Fifth Partners LLC: Interest Rate Swaps $ 250,000 June 7, 2017 June 7, 2027 2.677 % - 2.950 % Other Liabilities $ (7,247 ) Interest Rate Swaps 150,000 June 7, 2017 June 7, 2027 2.336 % - 2.430 % Prepaid Expenses and Other Assets 1,176 $ 400,000 $ (6,071 ) $ 950,000 $ (10,302 )
Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following table presents the location in the financial statements of the losses recognized related to the Company’s cash flow hedges for the years ended December 31, 2016 , 2015 and 2014 : Year ended December 31, 2016 2015 2014 (in thousands) Amount of loss related to the effective portion recognized in other comprehensive loss $ (47,144 ) $ (10,302 ) $ — Amount of loss related to the portion subsequently reclassified to earnings $ (3,751 ) (1) $ (2,510 ) $ (2,508 ) Amount of loss related to the ineffective portion and amount excluded from effectiveness testing $ (140 ) $ — $ — ___________ (1) During the year ended December 31, 2016, the Company accelerated the reclassification of amounts in other comprehensive loss to earnings as a result of the hedged forecasted transactions becoming probable not to occur. The accelerated amounts were a loss of approximately $0.2 million and are included in the table above.
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	Boston Properties, Inc. The following table reflects the changes in accumulated other comprehensive loss for the years ended December 31, 2016 , 2015 and 2014 (in thousands): Balance at December 31, 2013 $ (11,556 ) Amortization of interest rate contracts 2,508 Other comprehensive income attributable to noncontrolling interests (256 ) Balance at December 31, 2014 (9,304 ) Effective portion of interest rate contracts (10,302 ) Amortization of interest rate contracts 2,510 Other comprehensive loss attributable to noncontrolling interests 2,982 Balance at December 31, 2015 (14,114 ) Effective portion of interest rate contracts (47,144 ) Amortization of interest rate contracts 3,751 Other comprehensive loss attributable to noncontrolling interests 5,256 Balance at December 31, 2016 $ (52,251 )
Boston Properties Limited Partnership
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	Boston Properties Limited Partnership The following table reflects the changes in accumulated other comprehensive loss for the years ended December 31, 2016 , 2015 and 2014 (in thousands): Balance at December 31, 2013 $ (15,481 ) Amortization of interest rate contracts 2,508 Balance at December 31, 2014 (12,973 ) Effective portion of interest rate contracts (10,302 ) Amortization of interest rate contracts 2,510 Other comprehensive loss attributable to noncontrolling interests in property partnership 2,428 Balance at December 31, 2015 (18,337 ) Effective portion of interest rate contracts (47,144 ) Amortization of interest rate contracts 3,751 Other comprehensive loss attributable to noncontrolling interests in property partnership 877 Balance at December 31, 2016 $ (60,853 )

Unsecured Senior Notes (Tables)

Unsecured Senior Notes (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Schedule of Senior Notes	The following summarizes the unsecured senior notes outstanding as of December 31, 2016 (dollars in thousands): Coupon/ Stated Rate Effective Rate(1) Principal Amount Maturity Date(2) 10 Year Unsecured Senior Notes 5.875 % 5.967 % $ 700,000 October 15, 2019 10 Year Unsecured Senior Notes 5.625 % 5.708 % 700,000 November 15, 2020 10 Year Unsecured Senior Notes 4.125 % 4.289 % 850,000 May 15, 2021 7 Year Unsecured Senior Notes 3.700 % 3.853 % 850,000 November 15, 2018 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 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 Total principal 7,300,000 Net unamortized discount (18,783 ) Deferred financing costs, net (35,264 ) Total $ 7,245,953 _______________ (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.

Noncontrolling Interests (Table

Noncontrolling Interests (Tables)	12 Months Ended
	Dec. 31, 2016
Entity Information [Line Items]
Dividends Declared [Table Text Block]	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 payable in 2016: Record Date Payment Date Dividend (Per Share) Distribution (Per Unit) December 30, 2016 January 30, 2017 $0.75 $0.75 September 30, 2016 October 31, 2016 0.65 0.65 June 30, 2016 July 29, 2016 0.65 0.65 March 31, 2016 April 29, 2016 0.65 0.65 December 31, 2015 January 28, 2016 1.90 (1) 1.90 (1) _______________ (1) Includes a special dividend/distribution of $1.25 per share/OP Unit and LTIP Unit.
Schedule of Redeemable Interest in Property Partnerships [Table Text Block]	The following table reflects the activity of the noncontrolling interest—redeemable interest in property partnership in the Company’s Fountain Square consolidated entity for the years ended December 31, 2015 and 2013 (in thousands): Balance at December 31, 2013 $ 99,609 Net loss (603 ) Distributions (6,000 ) Adjustment to reflect redeemable interest at redemption value 11,686 Balance at December 31, 2014 104,692 Net loss (7 ) Distributions (2,900 ) Adjustment to reflect redeemable interest at redemption value 5,128 Acquisition of interest (106,913 ) Balance at December 31, 2015 $ —
Schedule Of Noncontrolling Interest Property Partnerships [Table Text Block]	The following table reflects the activity of the noncontrolling interests—property partnerships for the years ended December 31, 2016 , 2015 and 2014 (in thousands): Balance at December 31, 2013 $ 726,132 Capital contributions 887,975 Net income 19,478 Distributions (31,118 ) Balance at December 31, 2014 1,602,467 Capital contributions 3,758 Dissolution (4,082 ) Net income 144,734 Accumulated other comprehensive loss (2,428 ) Distributions (170,049 ) Balance at December 31, 2015 1,574,400 Capital contributions 10,756 Net loss (2,068 ) Accumulated other comprehensive loss (877 ) Distributions (51,564 ) Balance at December 31, 2016 $ 1,530,647
Boston Properties, Inc. [Member]
Entity Information [Line Items]
Schedule Of Redeemable Preferred Units of the Operating Partnership	The following table reflects the activity of the noncontrolling interests—redeemable preferred units of Boston Properties, Inc. for the years ended December 31, 2015 and 2014 (in thousands): Balance at December 31, 2013 $ 51,312 Net income 1,023 Distributions (1,023 ) Redemption of redeemable preferred units (Series Four Preferred Units) (17,373 ) Conversion of redeemable preferred units (Series Two Preferred Units) to common units (33,306 ) Balance at December 31, 2014 633 Net income 6 Distributions (6 ) Redemption of redeemable preferred units (Series Four Preferred Units) (633 ) Balance at December 31, 2015 $ —
Boston Properties Limited Partnership
Entity Information [Line Items]
Schedule Of Redeemable Preferred Units of the Operating Partnership	The following table reflects the activity of the noncontrolling interests—redeemable preferred units of Boston Properties Limited Partnership for the years ended December 31, 2015 and 2014 (in thousands): Balance at December 31, 2013 $ 105,746 Net income 1,023 Distributions (1,023 ) Redemption of redeemable preferred units (Series Four Preferred Units) (17,373 ) Reallocation of partnership interest (1) (87,740 ) Balance at December 31, 2014 633 Net income 6 Distributions (6 ) Redemption of redeemable preferred units (Series Four Preferred Units) (633 ) Balance at December 31, 2015 $ — _____________ (1) Includes the conversion of 666,116 Series Two Preferred Units into 874,168 OP Units during the year ended December 31, 2014 .
Schedule Of Noncontrolling Interest Common Units [Table Text Block]	The following table reflects the activity of noncontrolling interests—redeemable common units of Boston Properties Limited Partnership for the years ended December 31, 2016 , 2015 and 2014 (in thousands): Balance at December 31, 2013 $ 1,710,218 Contributions 23,990 Net income 50,862 Distributions (126,948 ) Conversion of redeemable partnership units (2,700 ) Unearned compensation (2,813 ) Other comprehensive income 256 Adjustment to reflect redeemable partnership units at redemption value 657,181 Balance at December 31, 2014 2,310,046 Contributions 39,030 Net income 66,951 Distributions (69,447 ) Conversion of redeemable partnership units (14,343 ) Unearned compensation (4,579 ) Other comprehensive loss (554 ) Adjustment to reflect redeemable partnership units at redemption value (40,415 ) Balance at December 31, 2015 2,286,689 Contributions 31,395 Net income 59,260 Distributions (49,087 ) Conversion of redeemable partnership units (6,461 ) Unearned compensation (3,464 ) Other comprehensive loss (4,379 ) Adjustment to reflect redeemable partnership units at redemption value (51,913 ) Balance at December 31, 2016 $ 2,262,040
Noncontrolling Interests [Member]
Entity Information [Line Items]
Dividends Declared [Table Text Block]	The following table presents Boston Properties Limited Partnership’s distributions on the OP Units and LTIP Units (including the 2012 OPP Units and, after the February 4, 2016 measurement date, the 2013 MYLTIP Units) and its distributions on the 2013 MYLTIP Units (prior to the February 4, 2016 measurement date), 2014 MYLTIP Units, 2015 MYLTIP Units and 2016 MYLTIP Units (after the February 10, 2016 issuance date) paid in 2016: Record Date Payment Date Distributions per OP Unit and LTIP Unit Distributions per MYLTIP Unit December 30, 2016 January 30, 2017 $0.75 $0.075 September 30, 2016 October 31, 2016 $0.65 $0.065 June 30, 2016 July 29, 2016 $0.65 $0.065 March 31, 2016 April 29, 2016 $0.65 $0.065 December 31, 2015 January 28, 2016 $1.90 (1) $0.065 _______________ (1) Includes a special distribution of $1.25 per unit.

Stockholders' Equity _ Partne39

Stockholders' Equity / Partners' Capital Stockholders Equity / Partners Capital (Tables)	12 Months Ended
	Dec. 31, 2016
Class of Stock [Line Items]
Dividends Declared [Table Text Block]	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 payable in 2016: Record Date Payment Date Dividend (Per Share) Distribution (Per Unit) December 30, 2016 January 30, 2017 $0.75 $0.75 September 30, 2016 October 31, 2016 0.65 0.65 June 30, 2016 July 29, 2016 0.65 0.65 March 31, 2016 April 29, 2016 0.65 0.65 December 31, 2015 January 28, 2016 1.90 (1) 1.90 (1) _______________ (1) Includes a special dividend/distribution of $1.25 per share/OP Unit and LTIP Unit.
Schedule Of Changes In Partners Capital Unit [Table Text Block] [Table Text Block]	The following table presents the changes in the issued and outstanding partners’ capital units since January 1, 2014: General Partner Units Limited Partner Units Total Partners’ Outstanding at December 31, 2013 1,700,222 151,282,879 152,983,101 Units issued to Boston Properties, Inc. related to Common Stock issued under the Employee Stock Purchase Plan 555 6,409 6,964 Units issued to Boston Properties, Inc. related to Common Stock issued under the Stock Option and Incentive Plan, net 3,476 40,158 43,634 Units issued to Boston Properties, Inc. related to Common Stock issued in exchange for OP Units 6,391 73,855 80,246 Outstanding at December 31, 2014 1,710,644 151,403,301 153,113,945 Units issued to Boston Properties, Inc. related to Common Stock issued under the Employee Stock Purchase Plan 59 6,140 6,199 Units issued to Boston Properties, Inc. related to Common Stock issued under the Stock Option and Incentive Plan, net 340 35,246 35,586 Units issued to Boston Properties, Inc. related to Common Stock issued in exchange for OP Units 4,049 420,187 424,236 Outstanding at December 31, 2015 1,715,092 151,864,874 153,579,966 Units issued to Boston Properties, Inc. related to Common Stock issued under the Employee Stock Purchase Plan 72 5,623 5,695 Units issued to Boston Properties, Inc. related to Common Stock issued under the Stock Option and Incentive Plan, net 172 13,485 13,657 Units issued to Boston Properties, Inc. related to Common Stock issued in exchange for OP Units 2,407 188,450 190,857 Outstanding at December 31, 2016 1,717,743 152,072,432 153,790,175
Schedule of changes in Series B Preferred Units [Table Text Block] [Table Text Block]	The following table reflects the activity of the Series B Preferred Units for the years ended December 31, 2016 , 2015 and 2014 (in thousands), which activity is included within Boston Properties Limited Partnership’s Consolidated Statements of Partners’ Capital: Balance at December 31, 2013 $ 193,623 Net income 10,500 Distributions (10,500 ) Balance at December 31, 2014 193,623 Net income 10,500 Distributions (10,500 ) Balance at December 31, 2015 193,623 Net income 10,500 Distributions (10,500 ) Balance at December 31, 2016 $ 193,623
Series B Preferred Stock [Member]
Class of Stock [Line Items]
Dividends Declared [Table Text Block]	The following table presents Boston Properties Inc.’s dividends per share on its outstanding Series B Preferred Stock paid or payable in 2016: Record Date Payment Date Dividend (Per Share) February 3, 2017 February 15, 2017 $32.8125 November 4, 2016 November 15, 2016 32.8125 August 5, 2016 August 15, 2016 32.8125 May 5, 2016 May 16, 2016 32.8125 February 5, 2016 February 16, 2016 32.8125

Future Minimum Rents (Tables)

Future Minimum Rents (Tables)	12 Months Ended
	Dec. 31, 2016
Future Minimum Rents [Abstract]
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	The future contractual minimum lease payments to be received (excluding operating expense reimbursements) by the Company as of December 31, 2016 , under non-cancelable operating leases which expire on various dates through 2046 , are as follows: Years Ending December 31, (in thousands) 2017 $ 1,906,847 2018 1,903,887 2019 1,887,137 2020 1,741,024 2021 1,553,526 Thereafter 9,367,433

Segment Information (Tables)

Segment Information (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Schedule Of Reconciliation Of Net Operating Income To Net Income	Boston Properties, Inc. Year ended December 31, 2016 2015 2014 (in thousands) Net income attributable to Boston Properties, Inc. common shareholders $ 502,285 $ 572,606 $ 433,111 Add: Preferred dividends 10,500 10,500 10,500 Noncontrolling interest—common units of the Operating Partnership 59,260 66,951 50,862 Noncontrolling interest—redeemable preferred units of the Operating Partnership — 6 1,023 Noncontrolling interest in property partnerships (2,068 ) 149,855 30,561 Losses from interest rate contracts 140 — — Losses from early extinguishments of debt 371 22,040 10,633 Interest expense 412,849 432,196 455,743 Depreciation and amortization expense 694,403 639,542 628,573 Impairment loss 1,783 — — Transaction costs 2,387 1,259 3,140 General and administrative expense 105,229 96,319 98,937 Less: Gains on sales of real estate 80,606 375,895 168,039 Gains (losses) from investments in securities 2,273 (653 ) 1,038 Interest and other income 7,230 6,777 8,765 Gain on sale of investment in unconsolidated joint venture 59,370 — — Income from unconsolidated joint ventures 8,074 22,770 12,769 Development and management services income 28,284 22,554 25,316 Net Operating Income $ 1,601,302 $ 1,563,931 $ 1,507,156 Boston Properties Limited Partnership Year ended December 31, 2016 2015 2014 (in thousands) Net income attributable to Boston Properties Limited Partnership common unitholders $ 575,341 $ 648,748 $ 499,129 Add: Preferred distributions 10,500 10,500 10,500 Noncontrolling interest—redeemable preferred units — 6 1,023 Noncontrolling interest in property partnerships (2,068 ) 149,855 30,561 Losses from interest rate contracts 140 — — Losses from early extinguishments of debt 371 22,040 10,633 Interest expense 412,849 432,196 455,743 Depreciation and amortization expense 682,776 631,549 620,064 Impairment loss 1,783 — — Transaction costs 2,387 1,259 3,140 General and administrative expense 105,229 96,319 98,937 Less: Gains on sales of real estate 82,775 377,093 174,686 Gains (losses) from investments in securities 2,273 (653 ) 1,038 Interest and other income 7,230 6,777 8,765 Gain on sale of investment in unconsolidated joint venture 59,370 — — Income from unconsolidated joint ventures 8,074 22,770 12,769 Development and management services income 28,284 22,554 25,316 Net Operating Income $ 1,601,302 $ 1,563,931 $ 1,507,156
Schedule Of Segment Information By Geographic Area And Property Type	Information by geographic area and property type (dollars in thousands): For the year ended December 31, 2016 : Boston New York San Francisco Washington, DC Total Rental Revenue: Office $ 727,265 $ 1,012,518 $ 318,609 $ 402,561 $ 2,460,953 Residential 4,812 — — 11,887 16,699 Hotel 44,884 — — — 44,884 Total 776,961 1,012,518 318,609 414,448 2,522,536 % of Grand Totals 30.80 % 40.14 % 12.63 % 16.43 % 100.00 % Rental Expenses: Office 282,827 363,188 100,787 135,890 882,692 Residential 2,708 — — 4,368 7,076 Hotel 31,466 — — — 31,466 Total 317,001 363,188 100,787 140,258 921,234 % of Grand Totals 34.41 % 39.42 % 10.94 % 15.23 % 100.00 % Net operating income $ 459,960 $ 649,330 $ 217,822 $ 274,190 $ 1,601,302 % of Grand Totals 28.73 % 40.55 % 13.60 % 17.12 % 100.00 % For the year ended December 31, 2015 : Boston New York San Francisco Washington, DC Total Rental Revenue: Office $ 716,246 $ 1,000,030 $ 302,434 $ 384,628 $ 2,403,338 Residential 4,801 — — 14,082 18,883 Hotel 46,046 — — — 46,046 Total 767,093 1,000,030 302,434 398,710 2,468,267 % of Grand Totals 31.08 % 40.52 % 12.25 % 16.15 % 100.00 % Rental Expenses: Office 287,341 346,897 98,206 131,581 864,025 Residential 2,006 — — 6,221 8,227 Hotel 32,084 — — — 32,084 Total 321,431 346,897 98,206 137,802 904,336 % of Grand Totals 35.54 % 38.36 % 10.86 % 15.24 % 100.00 % Net operating income $ 445,662 $ 653,133 $ 204,228 $ 260,908 $ 1,563,931 % of Grand Totals 28.50 % 41.76 % 13.06 % 16.68 % 100.00 % For the year ended December 31, 2014 : Boston New York San Francisco Washington, DC Total Rental Revenue: Office $ 715,917 $ 928,692 $ 261,221 $ 396,274 $ 2,302,104 Residential 4,528 — — 21,665 26,193 Hotel 43,385 — — — 43,385 Total 763,830 928,692 261,221 417,939 2,371,682 % of Grand Totals 32.21 % 39.16 % 11.01 % 17.62 % 100.00 % Rental Expenses: Office 278,120 315,330 90,133 135,785 819,368 Residential 1,957 — — 13,965 15,922 Hotel 29,236 — — — 29,236 Total 309,313 315,330 90,133 149,750 864,526 % of Grand Totals 35.78 % 36.47 % 10.43 % 17.32 % 100.00 % Net operating income $ 454,517 $ 613,362 $ 171,088 $ 268,189 $ 1,507,156 % of Grand Totals 30.16 % 40.70 % 11.35 % 17.79 % 100.00 %

Earnings Per Share _ Common U42

Earnings Per Share / Common Unit (Tables)	12 Months Ended
	Dec. 31, 2016
Entity Information [Line Items]
Computation Of Basic And Diluted Earnings Per Share / Unit	For the Year Ended December 31, 2016 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 $ 502,285 153,715 $ 3.27 Allocation of undistributed earnings to participating securities (283 ) — — Net income attributable to Boston Properties, Inc. common shareholders $ 502,002 153,715 $ 3.27 Effect of Dilutive Securities: Stock Based Compensation — 262 (0.01 ) Diluted Earnings: Net income attributable to Boston Properties, Inc. common shareholders $ 502,002 153,977 $ 3.26 For the Year Ended December 31, 2015 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 $ 572,606 153,471 $ 3.73 Effect of Dilutive Securities: Stock Based Compensation — 373 (0.01 ) Diluted Earnings: Net income attributable to Boston Properties, Inc. common shareholders $ 572,606 153,844 $ 3.72 For the Year Ended December 31, 2014 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 $ 433,111 153,089 $ 2.83 Effect of Dilutive Securities: Stock Based Compensation — 219 — Diluted Earnings: Net income attributable to Boston Properties, Inc. common shareholders $ 433,111 153,308 $ 2.83
Boston Properties Limited Partnership
Entity Information [Line Items]
Computation Of Basic And Diluted Earnings Per Share / Unit	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 17,646,000 , 17,668,000 and 17,364,000 redeemable common units for the years ended December 31, 2016 , 2015 and 2014 , respectively. For the Year Ended December 31, 2016 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 $ 575,341 171,361 $ 3.36 Allocation of undistributed earnings to participating securities (316 ) — — Net income attributable to Boston Properties Limited Partnership common unitholders $ 575,025 171,361 $ 3.36 Effect of Dilutive Securities: Stock Based Compensation — 262 (0.01 ) Diluted Earnings: Net income attributable to Boston Properties Limited Partnership common unitholders $ 575,025 171,623 $ 3.35 For the Year Ended December 31, 2015 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 $ 648,748 171,139 $ 3.79 Effect of Dilutive Securities: Stock Based Compensation — 373 (0.01 ) Diluted Earnings: Net income attributable to Boston Properties Limited Partnership common unitholders $ 648,748 171,512 $ 3.78 For the Year Ended December 31, 2014 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 $ 499,129 170,453 $ 2.93 Effect of Dilutive Securities: Stock Based Compensation — 219 (0.01 ) Diluted Earnings: Net income attributable to Boston Properties Limited Partnership common unitholders $ 499,129 170,672 $ 2.92

Stock Option and Incentive Pl43

Stock Option and Incentive Plan Stock Option and Incentive Plan and Stock Purchase Plan (Tables)	12 Months Ended
	Dec. 31, 2016
Stock Option and Incentive Plan and Stock Purchase Plan [Abstract]
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]	A summary of the status of Boston Properties, Inc.’s stock options as of December 31, 2016 , 2015 and 2014 and changes during the years then ended are presented below: Shares Weighted-Average Exercise Price Outstanding at December 31, 2013 558,823 $ 100.43 Exercised (21,459 ) $ 97.04 Canceled (2,444 ) $ 103.57 Special dividend adjustment 18,392 $ 97.22 Outstanding at December 31, 2014 553,312 $ 97.21 Exercised (11,447 ) $ 92.50 Special dividend adjustment 5,264 $ 96.38 Outstanding at December 31, 2015 547,129 $ 96.38 Exercised — $ — Outstanding at December 31, 2016 547,129 $ 96.38
Schedule of Stock Options Outstanding [Table Text Block]	The following table summarizes information about Boston Properties, Inc.’s stock options outstanding at December 31, 2016 : Options Outstanding Options Exercisable Number Outstanding at 12/31/16 Weighted-Average Remaining Contractual Life Exercise Price Number Exercisable at 12/31/16 Exercise Price 118,502 4.1 years $ 86.86 118,502 $ 86.86 54,282 6.3 years $ 95.69 40,711 $ 95.69 206,728 6.1 years $ 98.46 187,530 $ 98.46 167,617 5.1 years $ 100.77 167,617 $ 100.77

Selected Interim Financial In44

Selected Interim Financial Information (unaudited) (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information [Table Text Block]	2016 Quarter Ended March 31, June 30, September 30, December 31, (in thousands, except for per share amounts) Total revenue $ 665,985 $ 623,546 $ 625,228 $ 636,061 Income before gains on sales of real estate $ 148,599 $ 117,357 $ 58,521 $ 164,894 Net income attributable to Boston Properties, Inc. common shareholders $ 181,747 $ 96,597 $ 76,753 $ 147,214 Income attributable to Boston Properties, Inc. per share—basic $ 1.18 $ 0.63 $ 0.50 $ 0.96 Income attributable to Boston Properties, Inc. per share—diluted $ 1.18 $ 0.63 $ 0.50 $ 0.96 2015 Quarter Ended March 31, June 30, September 30, December 31, (in thousands, except for per share amounts) Total revenue $ 618,476 $ 618,221 $ 629,884 $ 624,240 Income before gains on sales of real estate $ 114,086 $ 100,739 $ 123,792 $ 85,406 Net income attributable to Boston Properties, Inc. common shareholders $ 171,182 $ 79,460 $ 184,082 $ 137,851 Income attributable to Boston Properties, Inc. per share—basic $ 1.12 $ 0.52 $ 1.20 $ 0.90 Income attributable to Boston Properties, Inc. per share—diluted $ 1.11 $ 0.52 $ 1.20 $ 0.90 Boston Properties Limited Partnership The tables below reflect Boston Properties Limited Partnership’s selected quarterly information for the years ended December 31, 2016 and 2015 . 2016 Quarter Ended March 31, June 30, September 30, December 31, (in thousands, except for per unit amounts) Total revenue $ 665,985 $ 623,546 $ 625,228 $ 636,061 Income before gains on sales of real estate $ 150,586 $ 119,341 $ 63,687 $ 167,384 Net income attributable to Boston Properties Limited Partnership common unitholders $ 207,296 $ 109,938 $ 91,306 $ 166,801 Income attributable to Boston Properties Limited Partnership per unit—basic $ 1.21 $ 0.64 $ 0.53 $ 0.97 Income attributable to Boston Properties Limited Partnership per unit—diluted $ 1.21 $ 0.64 $ 0.53 $ 0.97 2015 Quarter Ended March 31, June 30, September 30, December 31, (in thousands, except for per unit amounts) Total revenue $ 618,476 $ 618,221 $ 629,884 $ 624,240 Income before gains on sales of real estate $ 116,085 $ 102,737 $ 125,790 $ 87,404 Net income attributable to Boston Properties Limited Partnership common unitholders $ 193,369 $ 90,852 $ 207,626 $ 156,901 Income attributable to Boston Properties Limited Partnership per unit—basic $ 1.13 $ 0.53 $ 1.21 $ 0.92 Income attributable to Boston Properties Limited Partnership per unit—diluted $ 1.12 $ 0.53 $ 1.21 $ 0.92

Real Estate and Accumulated D45

Real Estate and Accumulated Depreciation Real Estate and Accumulated Depreciation (Tables)	12 Months Ended
	Dec. 31, 2016
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, By Property [Table Text Block]	Boston Properties, Inc. Schedule 3 - Real Estate and Accumulated Depreciation December 31, 2016 (dollars in thousands) Property Name Type Location Encumbrances Original Costs Capitalized Subsequent to Acquisition Land and Improvements Building and Improvements Land Held for Development Development and Construction in Progress Total Accumulated Depreciation Year(s) Built/ Renovated Year(s) Acquired Depreciable Lives (Years) Land Building 767 Fifth Avenue (the General Motors Building) Office New York, NY $ 1,333,625 $ 1,796,252 $ 1,532,654 $ 75,211 $ 1,796,252 $ 1,607,865 $ — $ — $ 3,404,117 $ 189,209 1968 2013 (1) Prudential Center Office Boston, MA — 92,077 734,594 656,606 115,638 1,214,787 — 152,852 1,483,277 482,661 1965/1993/2002/2016 1998/1999/2000 (1) Embarcadero Center Office San Francisco, CA — 179,697 847,410 343,726 195,987 1,174,846 — — 1,370,833 560,416 1970/1989 1998-1999 (1) 399 Park Avenue Office New York, NY — 339,200 700,358 132,062 354,107 817,513 — — 1,171,620 287,748 1961 2002 (1) 200 Clarendon Street and Garage Office Boston, MA — 219,543 667,884 115,996 219,616 777,557 6,250 — 1,003,423 140,629 1976 2010 (1) 601 Lexington Avenue Office New York, NY 684,858 241,600 494,782 196,359 289,639 620,487 — 22,615 932,741 239,984 1977/1997 2001 (1) 250 West 55th Street Office New York, NY — 285,263 603,167 35,668 285,263 638,835 — — 924,098 49,852 2014 2007 (1) Times Square Tower Office New York, NY — 165,413 380,438 87,583 169,193 464,241 — — 633,434 178,904 2004 2000 (1) Carnegie Center Office Princeton, NJ — 105,107 377,259 149,576 106,734 522,654 2,554 — 631,942 211,035 1983-2016 1998/1999/2000/2007/2014 (1) 100 Federal Street Office Boston, MA — 131,067 435,954 38,611 131,067 474,565 — — 605,632 77,409 1971-1975 2012 (1) Atlantic Wharf Office Boston, MA — 63,988 454,537 17,442 63,988 471,979 — — 535,967 85,984 2011 2007 (1) Fountain Square Office Reston, VA — 56,853 306,298 17,748 56,853 320,759 3,287 — 380,899 50,106 1986-1990 2012 (1) 510 Madison Avenue Office New York, NY — 103,000 253,665 21,952 103,000 275,617 — — 378,617 44,515 2012 2010 (1) 599 Lexington Avenue Office New York, NY — 81,040 100,507 169,222 87,852 262,917 — — 350,769 168,776 1986 1997 (1) 680 Folsom Street Office San Francisco, CA — 72,545 219,766 7,352 72,545 227,118 — — 299,663 21,845 2014 2012 (1) South of Market and Democracy Tower Office Reston, VA — 13,603 237,479 15,455 13,687 252,850 — — 266,537 79,868 2008-2009 2003 (1) 601 Massachusetts Avenue Office Washington, DC — 95,310 165,173 12 95,322 165,173 — — 260,495 6,534 2016 2008 (1) Bay Colony Corporate Center Office Waltham, MA — 18,789 148,451 68,371 18,789 216,822 — — 235,611 46,015 1985-1989 2011 (1) Gateway Center Office San Francisco, CA — 28,255 139,245 55,680 30,627 192,553 — — 223,180 98,003 1984/1986/2002 1999 (1) 535 Mission Street Office San Francisco, CA — 40,933 148,378 2,015 40,933 150,393 — — 191,326 8,844 2015 2013 (1) 2200 Pennsylvania Avenue Office Washington, DC — — 183,541 5,047 — 188,588 — — 188,588 39,956 2011 2008 (1) Mountain View Research Park Office Mountain View, CA — 95,066 68,373 6,491 95,066 74,864 — — 169,930 12,849 1977-1981/2007-2013 2013 (1) Reservoir Place Office Waltham, MA — 18,605 92,619 53,163 20,118 129,712 — 14,557 164,387 61,362 1955/1987 1997/1998 (1) 1330 Connecticut Avenue Office Washington, DC — 25,982 82,311 32,276 27,135 113,434 — — 140,569 34,137 1984 2004 (1) 1333 New Hampshire Avenue Office Washington, DC — 34,032 85,660 11,147 35,382 95,457 — — 130,839 37,996 1996 2003 (1) Kingstowne Towne Center Office Alexandria, VA — 18,021 109,038 1,083 18,062 110,080 — — 128,142 36,551 2003-2006 2007 (1) Capital Gallery Office Washington, DC — 4,725 29,565 89,028 8,662 114,656 — — 123,318 61,569 1981/2006 2007 (1) Boston Properties, Inc. Schedule 3 - Real Estate and Accumulated Depreciation December 31, 2016 (dollars in thousands) Property Name Type Location Encumbrances Original Costs Capitalized Subsequent to Acquisition Land and Improvements Building and Improvements Land Held for Development Development and Construction in Progress Total Accumulated Depreciation Year(s) Built/ Renovated Year(s) Acquired Depreciable Lives (Years) Land Building One Freedom Square Office Reston, VA — 9,929 84,504 28,646 11,293 111,786 — — 123,079 45,550 2000 2003 (1) Weston Corporate Center Office Weston, MA — 25,753 92,312 (123 ) 25,854 92,088 — — 117,942 20,074 2010 2001 (1) Two Freedom Square Office Reston, VA — 13,930 77,739 22,756 15,420 99,005 — — 114,425 44,569 2001 2003 (1) One and Two Reston Overlook Office Reston, VA — 16,456 66,192 24,634 16,179 91,103 — — 107,282 40,513 1999 2000 (1) Discovery Square Office Reston, VA — 11,198 71,782 22,642 12,533 93,089 — — 105,622 39,605 2001 2003 (1) 140 Kendrick Street Office Needham, MA — 18,095 66,905 15,466 19,092 81,374 — — 100,466 26,141 2000 2004 (1) 355 Main Street Office Cambridge, MA — 18,863 53,346 27,658 21,173 78,694 — — 99,867 25,345 1981/1996/2013 2006 (1) 90 Broadway Office Cambridge, MA — 19,104 52,078 17,048 20,785 67,445 — — 88,230 17,087 1983/1998/2013 2006 (1) 10 CityPoint Office Waltham, MA — 1,953 85,752 163 2,116 85,752 — — 87,868 1,601 2016 1997 (1) 230 CityPoint Office Waltham, MA — 13,189 49,823 20,187 13,593 69,606 — — 83,199 23,437 1992 2005 (1) Waltham Weston Corporate Center Office Waltham, MA — 10,385 60,694 10,889 11,097 70,871 — — 81,968 27,310 2003 1999 (1) 77 CityPoint Office Waltham, MA — 13,847 60,383 5,703 13,873 66,060 — — 79,933 20,981 2008 2001 (1) 3625-3635 Peterson Way Office Santa Clara, CA — 63,206 14,879 31 63,206 14,879 31 — 78,116 2,093 1979 2016 (1) North First Business Park Office San Jose, CA — 58,402 13,069 3,932 23,377 16,116 35,910 — 75,403 15,811 1981 2007 (1) 2440 West El Camino Real Office Mountain View, CA — 16,741 51,285 1,814 16,741 53,099 — — 69,840 9,817 1987/2003 2011 (1) 300 Binney Street Office Cambridge, MA — 18,080 51,262 140 18,080 51,402 — — 69,482 6,059 2013 2009 (1) Reston Corporate Center Office Reston, VA — 9,135 50,857 6,256 10,148 56,100 — — 66,248 25,244 1984 1998 (1) Wisconsin Place Office Chevy Chase, MD — — 53,349 9,884 — 63,233 — — 63,233 16,406 2009 2004 (1) New Dominion Technology Park, Bldg. Two Office Herndon, VA — 5,584 51,868 4,094 6,510 55,036 — — 61,546 21,908 2004 1998 (1) 200 West Street Office Waltham, MA — 16,148 24,983 10,102 16,813 34,420 — — 51,233 19,535 1999 1997 (1) New Dominion Technology Park, Bldg. One Office Herndon, VA 35,485 3,880 43,227 3,883 4,583 46,407 — — 50,990 24,362 2001 1998 (1) Sumner Square Office Washington, DC — 624 28,745 19,428 1,478 47,319 — — 48,797 22,237 1985 1999 (1) University Place Office Cambridge, MA 9,119 — 37,091 9,501 390 46,202 — — 46,592 25,207 1985 1998 (1) 2600 Tower Oaks Boulevard Office Rockville, MD — 4,243 31,125 9,081 4,785 39,664 — — 44,449 19,801 2001 1998 (1) 255 Main Street Office Cambridge, MA — 134 25,110 17,087 548 41,783 — — 42,331 27,499 1987 1997 (1) Quorum Office Park Office Chelmsford, MA — 3,750 32,454 5,813 5,187 36,830 — — 42,017 15,633 2001 2000 (1) 500 E Street Office Washington, DC — 109 22,420 13,219 2,379 33,369 — — 35,748 22,987 1987 1997 (1) 150 Broadway Office Cambridge, MA — 850 25,042 8,623 1,323 33,192 — — 34,515 15,545 1999 1997 (1) 325 Main Street Office Cambridge, MA — 174 12,200 12,256 965 23,665 — — 24,630 12,266 1987/2013 1997 (1) 105 Broadway Office Cambridge, MA — 1,299 12,943 7,198 2,395 19,045 — — 21,440 13,018 1990 1997 (1) Lexington Office Park Office Lexington, MA — 998 1,426 17,481 1,264 18,641 — — 19,905 12,490 1982 1997 (1) 40 Shattuck Road Office Andover, MA — 709 14,740 3,368 893 17,924 — — 18,817 7,505 2001 1997 (1) 201 Spring Street Office Lexington, MA — 2,849 15,303 14 3,124 15,042 — — 18,166 7,462 1997 1997 (1) The Point Office Waltham, MA — 6,395 10,040 408 6,480 10,363 — — 16,843 397 2015 2007 (1) 92-100 Hayden Avenue Office Lexington, MA — 594 6,748 8,181 802 14,721 — — 15,523 12,062 1985 1997 (1) 91 Hartwell Avenue Office Lexington, MA — 784 6,464 8,254 941 14,561 — — 15,502 9,062 1985 1997 (1) Boston Properties, Inc. Schedule 3 - Real Estate and Accumulated Depreciation December 31, 2016 (dollars in thousands) Property Name Type Location Encumbrances Original Costs Capitalized Subsequent to Acquisition Land and Improvements Building and Improvements Land Held for Development Development and Construction in Progress Total Accumulated Depreciation Year(s) Built/ Renovated Year(s) Acquired Depreciable Lives (Years) Land Building 690 Folsom Street Office San Francisco, CA — 3,219 11,038 1,157 3,219 12,195 — — 15,414 801 2015 2012 (1) 145 Broadway Office Cambridge, MA — 121 5,535 7,173 324 10,637 — 1,868 12,829 8,676 1984 1997 (1) 181 Spring Street Office Lexington, MA — 1,066 9,520 2,195 1,160 11,621 — — 12,781 4,876 1999 1997 (1) 195 West Street Office Waltham, MA — 1,611 6,652 4,340 1,858 10,745 — — 12,603 7,517 1990 1997 (1) 33 Hayden Avenue Office Lexington, MA — 266 3,234 8,787 425 11,862 — — 12,287 7,612 1979 1997 (1) 7501 Boston Boulevard, Building Seven Office Springfield, VA — 665 9,273 535 791 9,682 — — 10,473 4,596 1997 1997 (1) 7435 Boston Boulevard, Building One Office Springfield, VA — 392 3,822 5,116 659 8,671 — — 9,330 6,356 1982 1997 (1) 250 Binney Street Office Cambridge, MA — 110 4,483 3,593 273 7,913 — — 8,186 4,684 1983 1997 (1) 7450 Boston Boulevard, Building Three Office Springfield, VA — 1,165 4,681 1,807 1,430 6,223 — — 7,653 3,321 1987 1998 (1) 8000 Grainger Court, Building Five Office Springfield, VA — 366 4,282 2,607 601 6,654 — — 7,255 5,416 1984 1997 (1) 453 Ravendale Drive Office Mountain View, CA — 5,477 1,090 408 5,477 1,498 — — 6,975 338 1977 2012 (1) 7500 Boston Boulevard, Building Six Office Springfield, VA — 138 3,749 2,487 406 5,968 — — 6,374 4,538 1985 1997 (1) 17 Hartwell Avenue Office Lexington, MA — 26 150 6,109 65 6,220 — — 6,285 552 1968 1997 (1) 7601 Boston Boulevard, Building Eight Office Springfield, VA — 200 878 5,047 551 5,574 — — 6,125 4,043 1986 1997 (1) 7300 Boston Boulevard, Building Thirteen Office Springfield, VA — 608 4,773 709 661 5,429 — — 6,090 5,012 2002 1997 (1) 8000 Corporate Court, Building Eleven Office Springfield, VA — 136 3,071 1,615 775 4,047 — — 4,822 2,784 1989 1997 (1) 7375 Boston Boulevard, Building Ten Office Springfield, VA — 23 2,685 912 93 3,527 — — 3,620 2,472 1988 1997 (1) 7374 Boston Boulevard, Building Four Office Springfield, VA — 241 1,605 1,738 398 3,186 — — 3,584 2,452 1984 1997 (1) 7451 Boston Boulevard, Building Two Office Springfield, VA — 249 1,542 1,659 613 2,837 — — 3,450 2,330 1982 1997 (1) 32 Hartwell Avenue Office Lexington, MA — 168 1,943 1,012 314 2,809 — — 3,123 1,905 1968/1979/1987 1997 (1) 164 Lexington Road Office Billerica, MA — 592 1,370 319 643 1,638 — — 2,281 827 1982 1997 (1) The Avant at Reston Town Center Residential Reston, VA — 20,350 91,995 815 20,350 92,810 — — 113,160 7,306 2014 2010 (1) The Lofts at Atlantic Wharf Residential Boston, MA — 3,529 54,891 1,663 3,529 56,554 — — 60,083 8,105 2011 2007 (1) Boston Marriott Cambridge Hotel Cambridge, MA — 478 37,918 37,067 1,201 74,262 — — 75,463 50,954 1986 1997 (1) Kendall Center Green Garage Garage Cambridge, MA — — 35,035 7,391 103 42,323 — — 42,426 9,334 1984 2006 (1) Kendall Center Yellow Garage Garage Cambridge, MA — 1,256 15,697 1,571 1,434 17,090 — — 18,524 4,723 2006 2004 (1) Kendall Center Blue Garage Garage Cambridge, MA — 1,163 11,633 2,770 1,579 13,987 — — 15,566 9,325 1990 1997 (1) Salesforce Tower Development San Francisco, CA — — — 723,866 — — — 723,866 723,866 — N/A 2013 N/A Signature at Reston (formerly Reston Signature Site) Development Reston, VA — — — 96,444 — — — 96,444 96,444 — N/A 2013 N/A 191 Spring Street Development Lexington, MA — 2,850 27,166 3,134 3,151 28,576 — 1,423 33,150 21,660 1971/1995 1997 (1) Boston Properties, Inc. Schedule 3 - Real Estate and Accumulated Depreciation December 31, 2016 (dollars in thousands) Property Name Type Location Encumbrances Original Costs Capitalized Subsequent to Acquisition Land and Improvements Building and Improvements Land Held for Development Development and Construction in Progress Total Accumulated Depreciation Year(s) Built/ Renovated Year(s) Acquired Depreciable Lives (Years) Land Building Proto at Cambridge (formerly Cambridge Residential / 88 Ames) Development Cambridge, MA — — — 24,334 — — — 24,334 24,334 — N/A 2015 N/A Springfield Metro Center Land Springfield, VA — — — 35,430 — — 35,430 — 35,430 — N/A 2007 N/A Tower Oaks Master Plan Land Rockville, MD — — — 29,209 — — 29,209 — 29,209 — N/A 1998 N/A Plaza at Almaden Land San Jose, CA — — — 29,081 — — 29,081 — 29,081 — N/A 2006 N/A 6601 & 6605 Springfield Center Drive Land Springfield, VA — — — 13,866 — — 13,866 — 13,866 — N/A 2007 N/A 214 Third Avenue Land Waltham, MA — — — 13,795 — 146 13,649 — 13,795 — N/A 2006 N/A 103 Fourth Avenue Land Waltham, MA — — — 12,052 — 49 12,003 — 12,052 — N/A 2007 N/A 20 CityPoint Land Waltham, MA — — — 11,666 — — 11,666 — 11,666 — N/A 2007 N/A Reston Gateway Land Reston, VA — — — 10,841 — — 10,841 — 10,841 — N/A 1998 N/A Reston Eastgate Land Reston, VA — — — 9,906 — — 9,906 — 9,906 — N/A 2001 N/A Crane Meadow Land Marlborough, MA — — — 8,754 — — 8,754 — 8,754 — N/A 2000 N/A Washingtonian North Land Gaithersburg, MD — — — 7,697 — — 7,697 — 7,697 — N/A 1998 N/A Kendall Center Master Plan Land Cambridge, MA — — — 4,062 — — 4,062 — 4,062 — N/A N/A N/A Fourth and Harrison Land San Francisco, CA — — — 3,936 — — 3,936 — 3,936 — N/A N/A N/A North First Master Plan Land San Jose, CA — — — 3,014 — — 3,014 — 3,014 — N/A 2007 N/A Broad Run Business Park Land Loudoun County, VA — — — 2,694 — — 2,694 — 2,694 — N/A 1998 N/A MacArthur Station Land Oakland, CA — — — 1,316 — — 1,316 — 1,316 — N/A N/A N/A 30 Shattuck Road Land Andover, MA — — — 1,214 — — 1,214 — 1,214 — N/A 1997 N/A 2100 Pennsylvania Avenue Land Washington, DC — — — 286 — — 286 — 286 — N/A N/A N/A $ 2,063,087 (2 ) $ 4,759,821 $ 11,416,957 $ 3,937,798 $ 4,879,020 $ 13,950,941 $ 246,656 (3 ) $ 1,037,959 $ 20,114,576 $ 4,201,891 Note: Total Real Estate does not include Furniture, Fixtures and Equipment totaling approximately $32,687 . Accumulated Depreciation does not include approximately $20,344 of accumulated depreciation related to Furniture, Fixtures and Equipment. The aggregate cost and accumulated depreciation for tax purposes was approximately $15.8 billion and $3.2 billion , respectively. (1) Depreciation of the buildings and improvements are calculated over lives ranging from the life of the lease to 40 years. (2) Includes the unamortized balance of the historical fair value adjustment and unamortized deferred financing costs totaling approximately $33.8 million and $(2.4) million , respectively. (3) Includes pre-development costs.
Activity of Real Estate and Accumulated Depreciation [Table Text Block]	A summary of activity for real estate and accumulated depreciation is as follows: 2016 2015 2014 Real Estate: Balance at the beginning of the year $ 19,451,683 $ 19,208,417 $ 18,953,601 Additions to/improvements of real estate 977,287 700,792 594,296 Assets sold/written-off (314,394 ) (457,526 ) (339,480 ) Balance at the end of the year $ 20,114,576 $ 19,451,683 $ 19,208,417 Accumulated Depreciation: Balance at the beginning of the year $ 3,905,940 $ 3,529,978 $ 3,145,701 Depreciation expense 560,024 486,450 456,176 Assets sold/written-off (264,073 ) (110,488 ) (71,899 ) Balance at the end of the year $ 4,201,891 $ 3,905,940 $ 3,529,978 Note: Real Estate and Accumulated Depreciation amounts do not include Furniture, Fixtures and Equipment.
Boston Properties Limited Partnership
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, By Property [Table Text Block]	Boston Properties Limited Partnership Schedule 3—Real Estate and Accumulated Depreciation December 31, 2016 (dollars in thousands) Original Costs Capitalized Subsequent to Acquisition Land and Improvements Building and Improvements Land Held for Development Development and Construction in Progress Total Accumulated Depreciation Year(s) Built/ Renovated Year(s) Acquired Depreciable Lives (Years) Property Name Type Location Encumbrances Land Building 767 Fifth Avenue (the General Motors Building) Office New York, NY $ 1,333,625 $ 1,796,252 $ 1,532,654 $ 75,211 $ 1,796,252 $ 1,607,865 $ — $ — $ 3,404,117 $ 189,209 1968 2013 (1) Prudential Center Office Boston, MA — 92,077 734,594 596,236 100,540 1,169,515 — 152,852 1,422,907 470,161 1965/1993/2002/2016 1998/1999/2000 (1) Embarcadero Center Office San Francisco, CA — 179,697 847,410 281,345 180,420 1,128,032 — — 1,308,452 547,434 1970/1989 1998-1999 (1) 399 Park Avenue Office New York, NY — 339,200 700,358 72,454 339,200 772,812 — — 1,112,012 275,380 1961 2002 (1) 200 Clarendon Street and Garage Office Boston, MA — 219,543 667,884 115,996 219,616 777,557 6,250 — 1,003,423 140,629 1976 2010 (1) 250 West 55th Street Office New York, NY — 285,263 603,167 35,668 285,263 638,835 — — 924,098 49,852 2014 2007 (1) 601 Lexington Avenue Office New York, NY 684,858 241,600 494,782 159,273 279,281 593,759 — 22,615 895,655 232,590 1977/1997 2001 (1) Carnegie Center Office Princeton, NJ — 105,107 377,259 132,258 102,403 509,667 2,554 — 614,624 207,448 1983-2016 1998/1999/2000/2007/2014 (1) 100 Federal Street Office Boston, MA — 131,067 435,954 38,611 131,067 474,565 — — 605,632 77,409 1971-1975 2012 (1) Times Square Tower Office New York, NY — 165,413 380,438 49,604 159,694 435,761 — — 595,455 171,039 2004 2000 (1) Atlantic Wharf Office Boston, MA — 63,988 454,537 17,442 63,988 471,979 — — 535,967 85,984 2011 2007 (1) Fountain Square Office Reston, VA — 56,853 306,298 17,748 56,853 320,759 3,287 — 380,899 50,106 1986-1990 2012 (1) 510 Madison Avenue Office New York, NY — 103,000 253,665 21,952 103,000 275,617 — — 378,617 44,515 2012 2010 (1) 599 Lexington Avenue Office New York, NY — 81,040 100,507 141,980 81,040 242,487 — — 323,527 163,140 1986 1997 (1) 680 Folsom Street Office San Francisco, CA — 72,545 219,766 7,352 72,545 227,118 — — 299,663 21,845 2014 2012 (1) South of Market and Democracy Tower Office Reston, VA — 13,603 237,479 15,119 13,603 252,598 — — 266,201 79,814 2008-2009 2003 (1) 601 Massachusetts Avenue Office Washington, DC — 95,310 165,173 — 95,310 165,173 — — 260,483 6,534 2016 2008 (1) Bay Colony Corporate Center Office Waltham, MA — 18,789 148,451 68,371 18,789 216,822 — — 235,611 46,015 1985-1989 2011 (1) Gateway Center Office San Francisco, CA — 28,255 139,245 49,291 29,029 187,762 — — 216,791 96,681 1984/1986/2002 1999 (1) 535 Mission Street Office San Francisco, CA — 40,933 148,378 2,015 40,933 150,393 — — 191,326 8,844 2015 2013 (1) 2200 Pennsylvania Avenue Office Washington, DC — — 183,541 5,047 — 188,588 — — 188,588 39,956 2011 2008 (1) Mountain View Research Park Office Mountain View, CA — 95,066 68,373 6,491 95,066 74,864 — — 169,930 12,849 1977-1981/2007-2013 2013 (1) Reservoir Place Office Waltham, MA — 18,605 92,619 49,088 19,099 126,656 — 14,557 160,312 60,518 1955/1987 1997/1998 (1) 1330 Connecticut Avenue Office Washington, DC — 25,982 82,311 27,663 25,982 109,974 — — 135,956 33,179 1984 2004 (1) Kingstowne Towne Center Office Alexandria, VA — 18,021 109,038 919 18,021 109,957 — — 127,978 36,524 2003-2006 2007 (1) 1333 New Hampshire Avenue Office Washington, DC — 34,032 85,660 5,753 34,032 91,413 — — 125,445 36,878 1996 2003 (1) Weston Corporate Center Office Weston, MA — 25,753 92,312 (123 ) 25,854 92,088 — — 117,942 20,074 2010 2001 (1) One Freedom Square Office Reston, VA — 9,929 84,504 23,009 9,883 107,559 — — 117,442 44,381 2000 2003 (1) Capital Gallery Office Washington, DC — 4,725 29,565 78,897 6,128 107,059 — — 113,187 59,469 1981/2006 2007 (1) Two Freedom Square Office Reston, VA — 13,930 77,739 16,544 13,866 94,347 — — 108,213 43,283 2001 2003 (1) One and Two Reston Overlook Office Reston, VA — 16,456 66,192 20,216 15,074 87,790 — — 102,864 39,598 1999 2000 (1) Boston Properties Limited Partnership Schedule 3—Real Estate and Accumulated Depreciation December 31, 2016 (dollars in thousands) Original Costs Capitalized Subsequent to Acquisition Land and Improvements Building and Improvements Land Held for Development Development and Construction in Progress Total Accumulated Depreciation Year(s) Built/ Renovated Year(s) Acquired Depreciable Lives (Years) Property Name Type Location Encumbrances Land Building Discovery Square Office Reston, VA — 11,198 71,782 17,097 11,146 88,931 — — 100,077 38,454 2001 2003 (1) 355 Main Street Office Cambridge, MA — 18,863 53,346 27,360 21,098 78,471 — — 99,569 25,286 1981/1996/2013 2006 (1) 140 Kendrick Street Office Needham, MA — 18,095 66,905 11,476 18,095 78,381 — — 96,476 25,315 2000 2004 (1) 90 Broadway Office Cambridge, MA — 19,104 52,078 16,869 20,741 67,310 — — 88,051 17,056 1983/1998/2013 2006 (1) 10 CityPoint Office Waltham, MA — 1,953 85,752 — 1,953 85,752 — — 87,705 1,601 2016 1997 (1) 230 CityPoint Office Waltham, MA — 13,189 49,823 18,570 13,189 68,393 — — 81,582 23,106 1992 2005 (1) 77 CityPoint Office Waltham, MA — 13,847 60,383 5,598 13,847 65,981 — — 79,828 20,963 2008 2001 (1) Waltham Weston Corporate Center Office Waltham, MA — 10,385 60,694 7,902 10,350 68,631 — — 78,981 26,690 2003 1999 (1) 3625-3635 Peterson Way Office Santa Clara, CA — 63,206 14,879 31 63,206 14,879 31 — 78,116 2,093 1979 2016 (1) North First Business Park Office San Jose, CA — 58,402 13,069 3,909 23,371 16,099 35,910 — 75,380 15,811 1981 2007 (1) 2440 West El Camino Real Office Mountain View, CA — 16,741 51,285 1,814 16,741 53,099 — — 69,840 9,817 1987/2003 2011 (1) 300 Binney Street Office Cambridge, MA — 18,080 51,262 140 18,080 51,402 — — 69,482 6,059 2013 2009 (1) Reston Corporate Center Office Reston, VA — 9,135 50,857 3,645 9,496 54,141 — — 63,637 24,703 1984 1998 (1) Wisconsin Place Office Chevy Chase, MD — — 53,349 9,884 — 63,233 — — 63,233 16,406 2009 2004 (1) New Dominion Technology Park, Bldg. Two Office Herndon, VA — 5,584 51,868 349 5,574 52,227 — — 57,801 21,128 2004 1998 (1) 200 West Street Office Waltham, MA — 16,148 24,983 7,441 16,148 32,424 — — 48,572 18,983 1999 1997 (1) New Dominion Technology Park, Bldg. One Office Herndon, VA 35,485 3,880 43,227 1,073 3,880 44,300 — — 48,180 23,779 2001 1998 (1) Sumner Square Office Washington, DC — 624 28,745 17,348 958 45,759 — — 46,717 21,809 1985 1999 (1) University Place Office Cambridge, MA 9,119 — 37,091 8,051 27 45,115 — — 45,142 24,910 1985 1998 (1) 2600 Tower Oaks Boulevard Office Rockville, MD — 4,243 31,125 6,918 4,244 38,042 — — 42,286 19,351 2001 1998 (1) 255 Main Street Office Cambridge, MA — 134 25,110 15,431 134 40,541 — — 40,675 27,158 1987 1997 (1) Quorum Office Park Office Chelmsford, MA — 3,750 32,454 4,115 4,762 35,557 — — 40,319 15,282 2001 2000 (1) 150 Broadway Office Cambridge, MA — 850 25,042 6,618 822 31,688 — — 32,510 15,127 1999 1997 (1) 500 E Street Office Washington, DC — 109 22,420 9,979 1,569 30,939 — — 32,508 22,318 1987 1997 (1) 325 Main Street Office Cambridge, MA — 174 12,200 11,485 772 23,087 — — 23,859 12,104 1987/2013 1997 (1) 105 Broadway Office Cambridge, MA — 1,299 12,943 5,092 1,868 17,466 — — 19,334 12,580 1990 1997 (1) Lexington Office Park Office Lexington, MA — 998 1,426 16,717 1,073 18,068 — — 19,141 12,335 1982 1997 (1) 40 Shattuck Road Office Andover, MA — 709 14,740 2,632 709 17,372 — — 18,081 7,352 2001 1997 (1) 201 Spring Street Office Lexington, MA — 2,849 15,303 (1,085 ) 2,849 14,218 — — 17,067 7,233 1997 1997 (1) The Point Office Waltham, MA — 6,395 10,040 408 6,480 10,363 — — 16,843 397 2015 2007 (1) 690 Folsom Street Office San Francisco, CA — 3,219 11,038 1,157 3,219 12,195 — — 15,414 801 2015 2012 (1) 91 Hartwell Avenue Office Lexington, MA — 784 6,464 7,627 784 14,091 — — 14,875 8,930 1985 1997 (1) 92-100 Hayden Avenue Office Lexington, MA — 594 6,748 7,452 619 14,175 — — 14,794 11,910 1985 1997 (1) 181 Spring Street Office Lexington, MA — 1,066 9,520 1,818 1,066 11,338 — — 12,404 4,798 1999 1997 (1) 145 Broadway Office Cambridge, MA — 121 5,535 6,360 121 10,027 — 1,868 12,016 8,385 1984 1997 (1) Boston Properties Limited Partnership Schedule 3—Real Estate and Accumulated Depreciation December 31, 2016 (dollars in thousands) Original Costs Capitalized Subsequent to Acquisition Land and Improvements Building and Improvements Land Held for Development Development and Construction in Progress Total Accumulated Depreciation Year(s) Built/ Renovated Year(s) Acquired Depreciable Lives (Years) Property Name Type Location Encumbrances Land Building 33 Hayden Avenue Office Lexington, MA — 266 3,234 8,150 266 11,384 — — 11,650 7,480 1979 1997 (1) 195 West Street Office Waltham, MA — 1,611 6,652 3,351 1,611 10,003 — — 11,614 7,309 1990 1997 (1) 7501 Boston Boulevard, Building Seven Office Springfield, VA — 665 9,273 30 665 9,303 — — 9,968 4,490 1997 1997 (1) 7435 Boston Boulevard, Building One Office Springfield, VA — 392 3,822 4,423 486 8,151 — — 8,637 6,213 1982 1997 (1) 250 Binney Street Office Cambridge, MA — 110 4,483 2,939 110 7,422 — — 7,532 4,552 1983 1997 (1) 7450 Boston Boulevard, Building Three Office Springfield, VA — 1,165 4,681 1,393 1,327 5,912 — — 7,239 3,232 1987 1998 (1) 453 Ravendale Drive Office Mountain View, CA — 5,477 1,090 408 5,477 1,498 — — 6,975 338 1977 2012 (1) 8000 Grainger Court, Building Five Office Springfield, VA — 366 4,282 2,013 453 6,208 — — 6,661 5,294 1984 1997 (1) 17 Hartwell Avenue Office Lexington, MA — 26 150 5,952 26 6,102 — — 6,128 519 1968 1997 (1) 7300 Boston Boulevard, Building Thirteen Office Springfield, VA — 608 4,773 497 608 5,270 — — 5,878 4,968 2002 1997 (1) 7500 Boston Boulevard, Building Six Office Springfield, VA — 138 3,749 1,954 273 5,568 — — 5,841 4,428 1985 1997 (1) 7601 Boston Boulevard, Building Eight Office Springfield, VA — 200 878 4,354 378 5,054 — — 5,432 3,900 1986 1997 (1) 8000 Corporate Court, Building Eleven Office Springfield, VA — 136 3,071 1,264 687 3,784 — — 4,471 2,708 1989 1997 (1) 7375 Boston Boulevard, Building Ten Office Springfield, VA — 23 2,685 731 47 3,392 — — 3,439 2,437 1988 1997 (1) 7374 Boston Boulevard, Building Four Office Springfield, VA — 241 1,605 1,355 303 2,898 — — 3,201 2,375 1984 1997 (1) 7451 Boston Boulevard, Building Two Office Springfield, VA — 249 1,542 1,346 535 2,602 — — 3,137 2,264 1982 1997 (1) 32 Hartwell Avenue Office Lexington, MA — 168 1,943 426 168 2,369 — — 2,537 1,782 1968/1979/1987 1997 (1) 164 Lexington Road Office Billerica, MA — 592 1,370 117 592 1,487 — — 2,079 782 1982 1997 (1) The Avant at Reston Town Center Residential Reston, VA — 20,350 91,995 815 20,350 92,810 — — 113,160 7,306 2014 2010 (1) The Lofts at Atlantic Wharf Residential Boston, MA — 3,529 54,891 1,663 3,529 56,554 — — 60,083 8,105 2011 2007 (1) Boston Marriott Cambridge Hotel Cambridge, MA — 478 37,918 34,176 478 72,094 — — 72,572 50,357 1986 1997 (1) Kendall Center Green Garage Garage Cambridge, MA — — 35,035 6,977 — 42,012 — — 42,012 9,250 1984 2006 (1) Kendall Center Yellow Garage Garage Cambridge, MA — 1,256 15,697 859 1,256 16,556 — — 17,812 4,580 2006 2004 (1) Kendall Center Blue Garage Garage Cambridge, MA — 1,163 11,633 1,105 1,163 12,738 — — 13,901 8,982 1990 1997 (1) Salesforce Tower Development San Francisco, CA — — — 723,866 — — — 723,866 723,866 — N/A 2013 N/A Signature at Reston (formerly Reston Signature Site) Development Reston, VA — — — 96,444 — — — 96,444 96,444 — N/A 2013 N/A 191 Spring Street Development Lexington, MA — 2,850 27,166 1,935 2,850 27,678 — 1,423 31,951 21,001 1971/1995 1997 (1) Boston Properties Limited Partnership Schedule 3—Real Estate and Accumulated Depreciation December 31, 2016 (dollars in thousands) Original Costs Capitalized Subsequent to Acquisition Land and Improvements Building and Improvements Land Held for Development Development and Construction in Progress Total Accumulated Depreciation Year(s) Built/ Renovated Year(s) Acquired Depreciable Lives (Years) Property Name Type Location Encumbrances Land Building Proto at Cambridge (formerly Cambridge Residential / 88 Ames) Development Cambridge, MA — — — 24,334 — — — 24,334 24,334 — N/A 2015 N/A Springfield Metro Center Land Springfield, VA — — — 35,430 — — 35,430 — 35,430 — N/A 2007 N/A Tower Oaks Master Plan Land Rockville, MD — — — 29,209 — — 29,209 — 29,209 — N/A 1998 N/A Plaza at Almaden Land San Jose, CA — — — 29,081 — — 29,081 — 29,081 — N/A 2006 N/A 6601 & 6605 Springfield Center Drive Land Springfield, VA — — — 13,866 — — 13,866 — 13,866 — N/A 2007 N/A 214 Third Avenue Land Waltham, MA — — — 13,795 — 146 13,649 — 13,795 — N/A 2006 N/A 103 Fourth Avenue Land Waltham, MA — — — 12,052 — 49 12,003 — 12,052 — N/A 2007 N/A 20 CityPoint Land Waltham, MA — — — 11,666 — — 11,666 — 11,666 — N/A 2007 N/A Reston Gateway Land Reston, VA — — — 10,841 — — 10,841 — 10,841 — N/A 1998 N/A Reston Eastgate Land Reston, VA — — — 9,906 — — 9,906 — 9,906 — N/A 2001 N/A Crane Meadow Land Marlborough, MA — — — 8,754 — — 8,754 — 8,754 — N/A 2000 N/A Washingtonian North Land Gaithersburg, MD — — — 7,697 — — 7,697 — 7,697 — N/A 1998 N/A Kendall Center Master Plan Land Cambridge, MA — — — 4,062 — — 4,062 — 4,062 — N/A N/A N/A Fourth and Harrison Land San Francisco, CA — — — 3,936 — — 3,936 — 3,936 — N/A N/A N/A North First Master Plan Land San Jose, CA — — — 3,014 — — 3,014 — 3,014 — N/A 2007 N/A Broad Run Business Park Land Loudoun County, VA — — — 2,694 — — 2,694 — 2,694 — N/A 1998 N/A MacArthur Station Land Oakland, CA — — — 1,316 — — 1,316 — 1,316 — N/A N/A N/A 30 Shattuck Road Land Andover, MA — — — 1,214 — — 1,214 — 1,214 — N/A 1997 N/A 2100 Pennsylvania Avenue Land Washington, DC — — — 286 — — 286 — 286 — N/A N/A N/A $ 2,063,087 (2 ) $ 4,759,821 $ 11,416,957 $ 3,524,407 $ 4,774,460 $ 13,642,110 $ 246,656 (3 ) $ 1,037,959 $ 19,701,185 $ 4,116,020 Note: Total Real Estate does not include Furniture, Fixtures and Equipment totaling approximately $32,687 . Accumulated Depreciation does not include approximately $20,344 of accumulated depreciation related to Furniture, Fixtures and Equipment. The aggregate cost and accumulated depreciation for tax purposes was approximately $17.6 billion and $3.6 billion , respectively. (1) Depreciation of the buildings and improvements are calculated over lives ranging from the life of the lease to 40 years. (2) Includes the unamortized balance of the historical fair value adjustment and unamortized deferred financing costs totaling approximately $33.8 million and $(2.4) million , respectively. (3) Includes pre-development costs.
Activity of Real Estate and Accumulated Depreciation [Table Text Block]	A summary of activity for real estate and accumulated depreciation is as follows: 2016 2015 2014 Real Estate: Balance at the beginning of the year $ 19,031,289 $ 18,786,572 $ 18,523,277 Additions to/improvements of real estate 977,287 700,792 594,296 Assets sold/written-off (307,391 ) (456,075 ) (331,001 ) Balance at the end of the year $ 19,701,185 $ 19,031,289 $ 18,786,572 Accumulated Depreciation: Balance at the beginning of the year $ 3,826,862 $ 3,458,640 $ 3,081,040 Depreciation expense 548,397 478,457 447,667 Assets sold/written-off (259,239 ) (110,235 ) (70,067 ) Balance at the end of the year $ 4,116,020 $ 3,826,862 $ 3,458,640 Note: Real Estate and Accumulated Depreciation amounts do not include Furniture, Fixtures and Equipment.

Organization (Details)

Organization (Details) ft² in Millions	12 Months Ended
	Dec. 31, 2016ft²Real_Estate_Propertiesyrshares	Dec. 31, 2015shares
Real Estate Properties [Line Items]
General and limited partnership interest in the operating partnership (percent)	89.50%	89.50%
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	1
Commercial Real Estate Properties [Member]
Real Estate Properties [Line Items]
Number of real estate properties	174
Net Rentable Area | ft²	47.7
Total Properties Under Construction [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	8
Net Rentable Area | ft²	4
Total Office Properties [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	164
Office Properties Under Construction [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	6
Hotel Property [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	1
Retail Properties [ Member]
Real Estate Properties [Line Items]
Number of real estate properties	5
Residential Properties [Member]
Real Estate Properties [Line Items]
Number of real estate properties	4
Residential Properties Under Construction [Member]
Real Estate Properties [Line Items]
Number of real estate properties	2
Series B Cumulative Redeemable Preferred Stock / Unit [Member]
Real Estate Properties [Line Items]
Preferred stock / units, shares / units outstanding (in shares / units) | shares	80,000	80,000
Preferred Stock, Dividend Rate, Percentage	5.25%
Depositary shares of Series B Cumulative Redeemable Preferred [Member]
Real Estate Properties [Line Items]
Preferred stock / units, shares / units outstanding (in shares / units) | shares	8,000,000
Series B Preferred Units [Member]
Real Estate Properties [Line Items]
Preferred stock / units, shares / units outstanding (in shares / units) | shares	80,000

Summary Of Significant Accoun47

Summary Of Significant Accounting Policies (Narrative) (Details)	12 Months Ended
	Dec. 31, 2016USD ($)yr	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Entity Information [Line Items]
Probable Sale Term of Property After Classified As Held For Sale (Years) | yr	1
Maximum Period After Construction The Company Considers A Construction Project As Substantially Completed (In Years) | yr	1
Interest costs capitalized	$ 39,237,000	$ 34,213,000	$ 52,476,000
Salaries And Related Costs Capitalized	11,100,000	10,400,000	8,500,000
Cash FDIC Insured Limit	250,000
Separate Unrestricted Cash For Deferred Compensation Plan.	23,800,000	20,400,000
Gains (losses) from investments in securities	2,273,000	(653,000)	1,038,000
Internal Leasing Salaries And Related Costs Capitalized	7,200,000	5,500,000	6,000,000
Straight-line rent adjustments	(31,700,000)	(80,000,000)	(63,100,000)
Above and below market rent adjustments, net	$ 30,200,000	35,900,000	48,300,000
Ground Lease Expiration Date, Maximum	2,114
REIT Annual Taxable Income Distribution Requirement Percentage, Minimum	90.00%
Company Annual Taxable Income Distribution Percentage	100.00%
Net Difference Between Tax Basis And Company's Assets And Liabilities.	$ 1,700,000,000	1,600,000,000
Deferred Finance Costs, Net	2,358,000
Boston Properties Limited Partnership
Entity Information [Line Items]
Interest costs capitalized	39,237,000	34,213,000	52,476,000
Gains (losses) from investments in securities	2,273,000	(653,000)	$ 1,038,000
Net Difference Between Tax Basis And Company's Assets And Liabilities.	2,700,000,000	2,600,000,000
Deferred Finance Costs, Net	(2,400,000)
Mortgages [Member]
Entity Information [Line Items]
Deferred Finance Costs, Net	2,400,000	3,500,000
Unsecured Debt [Member]
Entity Information [Line Items]
Deferred Finance Costs, Net	35,300,000	24,500,000
Line of Credit [Member]
Entity Information [Line Items]
Deferred Finance Costs, Net	$ 1,900,000	$ 3,100,000

Summary Of Significant Accoun48

Summary Of Significant Accounting Policies Schedule of Estimated Useful Lives (Details)	12 Months Ended
	Dec. 31, 2016
Land Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (years)	25 years
Land Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (years)	40 years
Building and Building Improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (years)	10 years
Building and Building Improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (years)	40 years
Tenant Improvement [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life, description	Shorter of useful life or terms of related lease
Furniture, fixtures and equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (years)	3 years
Furniture, fixtures and equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Estimated useful life (years)	7 years

Summary Of Significant Accoun49

Summary Of Significant Accounting Policies Schedule of Finite Lived Intangible Assets Future Amortization Expense (Details) $ in Thousands	Dec. 31, 2016USD ($)
Finite-Lived Intangible Assets [Line Items]
2,017	$ 37,547
2,018	32,831
2,019	26,556
2,020	13,885
2,021	8,365
Acquired Above-Market Lease Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
2,017	11,697
2,018	8,609
2,019	7,100
2,020	5,394
2,021	2,988
Acquired Below-Market Lease Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
2,017	33,871
2,018	32,156
2,019	27,318
2,020	10,736
2,021	$ 6,294

Summary Of Significant Accoun50

Summary Of Significant Accounting Policies Schedule Of Future Contractual Minimum Lease Payments Under Non-Cancelable Ground Leases (Details) $ in Thousands	Dec. 31, 2016USD ($)
Summary of Significant Accounting Policies [Abstract]
2,017	$ 12,554
2,018	28,781
2,019	17,868
2,020	9,870
2,021	9,492
Thereafter	$ 585,209

Summary Of Significant Accoun51

Summary Of Significant Accounting Policies (Carrying Value Of Indebtedness And Corresponding Estimate Of Fair Value) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable, net	$ 2,063,087	$ 3,435,242
Mezzanine notes payable	307,093	308,482
Unsecured senior notes, net	7,245,953	5,264,819
Total	2,031,615
Carrying Amount [Member]
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable, net	2,063,087	3,435,242
Mezzanine notes payable	307,093	308,482
Unsecured senior notes, net	7,245,953	5,264,819
Total	9,616,133	9,008,543
Estimated Fair Value [Member]
Summary Of Significant Accounting Policies [Line Items]
Mortgage notes payable, net	2,092,237	3,503,746
Mezzanine notes payable	308,344	306,103
Unsecured senior notes, net	7,428,077	5,547,738
Total	$ 9,828,658	$ 9,357,587

Summary Of Significant Accoun52

Summary Of Significant Accounting Policies Schedule of Tax Treatment Of Common Dividends Per Share For Federal Tax Purposes (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014		Dec. 19, 2016	Jan. 28, 2016
Tax Treatment Of Common Dividends Per Share For Federal Tax Purposes [Line Items]
Dividends Payable, Amount Per Share							$ 0.75
Special dividend (per share amount)			$ 1.25		$ 4.50			$ 1.25
Dividends Treatment For Federal Tax Purposes, Percentage	100.00%		100.00%		100.00%
Dividends treatment for federal tax purposes.	$ 3.05	[1]	$ 4.04	[2]	$ 6.82	[3]
Dividend Declared
Tax Treatment Of Common Dividends Per Share For Federal Tax Purposes [Line Items]
Dividends Payable, Amount Per Share	0.75		1.90		5.15
non-special dividend
Tax Treatment Of Common Dividends Per Share For Federal Tax Purposes [Line Items]
Dividends Payable, Amount Per Share			0.65		0.65
Allocated to fiscal 2014
Tax Treatment Of Common Dividends Per Share For Federal Tax Purposes [Line Items]
Dividends Payable, Amount Per Share					4.41
Allocated to fiscal 2015
Tax Treatment Of Common Dividends Per Share For Federal Tax Purposes [Line Items]
Dividends Payable, Amount Per Share					$ 0.74
Special dividend (per share amount)			1.35
Allocated to fiscal 2016
Tax Treatment Of Common Dividends Per Share For Federal Tax Purposes [Line Items]
Special dividend (per share amount)	0.56		$ 0.55
Allocated to fiscal 2017
Tax Treatment Of Common Dividends Per Share For Federal Tax Purposes [Line Items]
Special dividend (per share amount)	$ 0.19
Capital Gains Income
Tax Treatment Of Common Dividends Per Share For Federal Tax Purposes [Line Items]
Dividends Treatment For Federal Tax Purposes, Percentage	9.49%		42.03%		100.00%
Dividends treatment for federal tax purposes.	$ 0.29		$ 1.70		$ 6.82
Ordinary Income
Tax Treatment Of Common Dividends Per Share For Federal Tax Purposes [Line Items]
Dividends Treatment For Federal Tax Purposes, Percentage	90.51%		57.97%		0.00%
Dividends treatment for federal tax purposes.	$ 2.76		$ 2.34		$ 0
[1]	The fourth quarter 2016 regular quarterly dividend was $0.75 per common share of which approximately $0.56 per common share was allocable to 2016 and approximately $0.19 per common share is allocable to 2017.
[2]	The fourth quarter 2015 dividend of $1.90 per common share consists of a $1.25 per common share special dividend and a $0.65 per common share regular quarterly dividend. Approximately $1.35 per common share was allocable to 2015 and approximately $0.55 per common share is allocable to 2016.
[3]	The fourth quarter 2014 dividend of $5.15 per common share consists of a $4.50 per common share special dividend and a $0.65 per common share regular quarterly dividend. Approximately $4.41 per common share was allocable to 2014 and approximately $0.74 per common share is allocable to 2015.

Summary Of Significant Accoun53

Summary Of Significant Accounting Policies GAAP Reconciliation Of Net Income To Taxable Income (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Entity Information [Line Items]
Net income attributable to the Company		$ 147,214	$ 76,753	$ 96,597	$ 181,747	$ 137,851	$ 184,082	$ 79,460	$ 171,182	$ 512,785	$ 583,106	$ 443,611
Straight line rent and net above and below-market rent adjustments										(65,861)	(92,483)	(91,733)
Book/tax differences from depreciation and amortization										235,819	307,115	239,681
Book/Tax differences from interest expense										(36,223)	(43,349)	(43,148)
Book/tax differences on gains/(losses) from capital transactions										(70,880)	(74,482)	943,778	[1]
Book/tax differences from stock-based compensation										33,463	22,008	32,483
Tangible Property Regulations	[2]									(104,783)	(74,887)	(442,650)
Other book/tax differences, net										(6,121)	(15,259)	(7,945)
Taxable Income										498,199	611,769	1,074,077
One-time deduction for Tangible Repair Regulations												385,600
Boston Properties Limited Partnership
Entity Information [Line Items]
Net income attributable to the Company		$ 166,801	$ 91,306	$ 109,938	$ 207,296	$ 156,901	$ 207,626	$ 90,852	$ 193,369	585,841	659,248	509,629
Straight line rent and net above and below-market rent adjustments										(73,604)	(103,227)	(102,319)
Book/tax differences from depreciation and amortization										245,239	329,629	253,590
Book/Tax differences from interest expense										(40,481)	(48,385)	(48,128)
Book/tax differences on gains/(losses) from capital transactions										(69,683)	(67,602)	1,065,518	[3]
Book/tax differences from stock-based compensation										37,397	24,565	36,232
Tangible Property Regulations	[4]									(117,102)	(83,587)	(493,731)
Other book/tax differences, net										(3,387)	(14,561)	(11,403)
Taxable Income										$ 564,220	$ 696,080	1,209,388
One-time deduction for Tangible Repair Regulations												$ 430,100
[1]	Consists primarily of the gain on sale of real estate for tax purposes related to the October 2014 sale by the Company of a 45% interest in each of 601 Lexington Avenue in New York City and Atlantic Wharf Office Building and 100 Federal Street in Boston, which was accounted for as an equity transaction for GAAP purposes with no gain on sale of real estate recognized
[2]	In September 2013, the Internal Revenue Service released final Regulations governing when taxpayers like Boston Properties, Inc. must capitalize and depreciate costs for acquiring, maintaining, repairing and replacing tangible property and when taxpayers can deduct such costs. These final Regulations were effective for tax years beginning on or after January 1, 2014. These Regulations permitted Boston Properties, Inc. to deduct certain types of expenditures that were previously required to be capitalized. The Regulations also allowed Boston Properties, Inc. to make a one-time election in 2014 to immediately deduct certain amounts that were capitalized in previous years that are not required to be capitalized under the new Regulations. The one-time deduction included above totaled approximately $385.6 million for the year ended December 31, 2014.
[3]	Consists primarily of the gain on sale of real estate for tax purposes related to the October 2014 sale by the Company of a 45% interest in each of 601 Lexington Avenue in New York City and Atlantic Wharf Office Building and 100 Federal Street in Boston, which was accounted for as an equity transaction for GAAP purposes with no gain on sale of real estate recognized
[4]	In September 2013, the Internal Revenue Service released final Regulations governing when taxpayers like Boston Properties Limited Partnership must capitalize and depreciate costs for acquiring, maintaining, repairing and replacing tangible property and when taxpayers can deduct such costs. These final Regulations were effective for tax years beginning on or after January 1, 2014. These Regulations permitted Boston Properties Limited Partnership to deduct certain types of expenditures that were previously required to be capitalized. The Regulations also allowed Boston Properties Limited Partnership to make a one-time election in 2014 to immediately deduct certain amounts that were capitalized in previous years that are not required to be capitalized under the new Regulations. The one-time deduction included above totaled approximately $430.1 million for the year ended December 31, 2014.

Real Estate Schedule of Real Es

Real Estate Schedule of Real Estate Properties (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
Real Estate Properties [Line Items]
Land		$ 4,879,020	$ 4,806,021
Land held for future development	[1]	246,656	252,195
Buildings and improvements		11,890,626	11,709,285
Tenant improvements		2,060,315	1,920,247
Furniture, fixtures and equipment		32,687	29,852
Construction in progress		1,037,959	763,935
Total		20,147,263	19,481,535
Less: accumulated depreciation		(4,222,235)	(3,925,894)
Total real estate		15,925,028	15,555,641
Boston Properties Limited Partnership
Real Estate Properties [Line Items]
Land		4,774,460	4,700,793
Land held for future development	[1]	246,656	252,195
Buildings and improvements		11,581,795	11,394,119
Tenant improvements		2,060,315	1,920,247
Furniture, fixtures and equipment		32,687	29,852
Construction in progress		1,037,959	763,935
Total		19,733,872	19,061,141
Less: accumulated depreciation		(4,136,364)	(3,846,816)
Total real estate		$ 15,597,508	$ 15,214,325
[1]	Includes pre-development costs.

Real Estate (Narrative) (Detail

Real Estate (Narrative) (Details) $ in Thousands	Dec. 06, 2016USD ($)ft²yr	Aug. 19, 2016USD ($)ft²floor	Aug. 16, 2016USD ($)	Feb. 01, 2016USD ($)ft²	Jan. 31, 2016USD ($)	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 29, 2016ft²	Nov. 14, 2016USD ($)	Nov. 07, 2016ft²yr	Oct. 24, 2016apartments	Sep. 16, 2016ft²	Jun. 24, 2016ft²	May 27, 2016ft²	Apr. 22, 2016USD ($)ft²	Feb. 03, 2016ft²
Real Estate Properties [Line Items]
Payments to Acquire and Develop Real Estate															$ 78,000	$ 0	$ 4,670
Total revenue						$ 636,061	$ 625,228	$ 623,546	$ 665,985	$ 624,240	$ 629,884	$ 618,221	$ 618,476		2,550,820	2,490,821	2,396,998
Earnings															825,784	849,365	801,822
Proceeds from sales of real estate															122,750	602,600	419,864
Prepaid ground rent						129,666				185,118				$ 129,666	129,666	185,118
Accelerated depreciation related to redevelopment															694,403	639,542	628,573
Accelerated depreciation associated with redevelompent allocated to the outside partners'															(2,068)	149,855	30,561
Impairment loss															1,783	0	0
Gains on sales of real estate															80,606	375,895	168,039
Impairment loss															1,783	0	0
3625-3635 Peterson Way
Real Estate Properties [Line Items]
Net assets acquired																									$ 78,000
Total revenue														3,900
Earnings														200
Net Rentable Area | ft²																									218,000
Portion of Building Leased (percentage)																									100.00%
415 Main Street
Real Estate Properties [Line Items]
Earnings					$ 1,200											8,300	8,200
Proceeds from sales of real estate				$ 104,900
Net Rentable Area | ft²				231,000
Sale Price Of Sold Property				$ 105,400
Gains on sales of real estate				60,800
Broad Run Business Park
Real Estate Properties [Line Items]
Proceeds from sales of real estate			$ 17,900
Sale Price Of Sold Property			18,000
Gains on sales of real estate			$ 13,000
601 Lexington Avenue | Consolidated Properties [Member]
Real Estate Properties [Line Items]
Ownership Percentage by Parent		55.00%
Number of floors in building | floor		6
Accelerated depreciation related to redevelopment		$ 50,800
Accelerated depreciation associated with redevelompent allocated to the outside partners'		$ 21,400
888 Boylston Street
Real Estate Properties [Line Items]
Net Rentable Area | ft²																						425,000
145 Broadway
Real Estate Properties [Line Items]
Term of Lease Signed (in years) | yr																				15
191 Spring Street
Real Estate Properties [Line Items]
Net Rentable Area | ft²																		160,000
601 Massachusetts Avenue
Real Estate Properties [Line Items]
Net Rentable Area | ft²																								479,000
804 Carnegie Center [Member]
Real Estate Properties [Line Items]
Net Rentable Area | ft²																								130,000
10 CityPoint
Real Estate Properties [Line Items]
Net Rentable Area | ft²																							241,000
MacArthur Station
Real Estate Properties [Line Items]
Number of apartment units | apartments																					400
2100 Pennsylvania Avenue [Member]
Real Estate Properties [Line Items]
Ground Lease Term (in years) | yr	75
Prepaid ground rent	$ 15,000
Future development [Member] | 3625-3635 Peterson Way
Real Estate Properties [Line Items]
Net Rentable Area | ft²																									632,000
Future development [Member] | 145 Broadway
Real Estate Properties [Line Items]
Net Rentable Area | ft²																				476,500
Future development [Member] | 2100 Pennsylvania Avenue [Member]
Real Estate Properties [Line Items]
Net Rentable Area | ft²	482,000
Land [Member] | Washingtonian North
Real Estate Properties [Line Items]
Contractual Sales Price																			$ 7,800
Impairment loss															1,800
Office Building [Member] | 601 Lexington Avenue | Consolidated Properties [Member]
Real Estate Properties [Line Items]
Net Rentable Area | ft²		195,000
Office Building [Member] | 145 Broadway
Real Estate Properties [Line Items]
Net Rentable Area | ft²																				80,000
Retail Site [Member] | 601 Lexington Avenue | Consolidated Properties [Member]
Real Estate Properties [Line Items]
Net Rentable Area | ft²		25,000
Terminated lease at 250 West 55th Street in NYC [Member]
Real Estate Properties [Line Items]
Total revenue															45,000
Net Rentable Area | ft²																										85,000
Boston Properties Limited Partnership
Real Estate Properties [Line Items]
Payments to Acquire and Develop Real Estate															78,000	0	4,670
Total revenue						636,061	$ 625,228	$ 623,546	$ 665,985	624,240	$ 629,884	$ 618,221	$ 618,476		2,550,820	2,490,821	2,396,998
Earnings															837,411	857,358	810,331
Proceeds from sales of real estate															122,750	602,600	419,864
Prepaid ground rent						$ 129,666				$ 185,118				$ 129,666	129,666	185,118
Accelerated depreciation related to redevelopment															682,776	631,549	620,064
Accelerated depreciation associated with redevelompent allocated to the outside partners'															(2,068)	149,855	30,561
Impairment loss															1,783	0	0
Gains on sales of real estate															82,775	377,093	174,686
Impairment loss															$ 1,783	$ 0	$ 0
Boston Properties Limited Partnership | 415 Main Street
Real Estate Properties [Line Items]
Gains on sales of real estate				$ 63,000
Boston Properties Limited Partnership | 601 Lexington Avenue | Consolidated Properties [Member]
Real Estate Properties [Line Items]
Accelerated depreciation related to redevelopment		$ 47,600

Real Estate Real Estate Activit

Real Estate Real Estate Activity Purchase Price Allocation (Details) - 3625-3635 Peterson Way $ in Thousands	Apr. 22, 2016USD ($)
Business Acquisition [Line Items]
Land	$ 63,206
Building and improvements	7,210
Tenant Improvements	7,669
In-place lease Intangibles	4,262
Below-market lease intangible	(4,347)
Net assets acquired	$ 78,000

Real Estate Real Estate Intangi

Real Estate Real Estate Intangible Assets Amortization Table (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Apr. 22, 2016
Acquired Finite-Lived Intangible Assets [Line Items]
2,017	$ 32,831
2,018	26,556
2,019	13,885
2,020	$ 8,365
3625-3635 Peterson Way | Acquired in-place lease intangibles
Acquired Finite-Lived Intangible Assets [Line Items]
Period from April 22, 2016 through December 31, 2016		$ 296
2,017		444
2,018		444
2,019		444
2,020		444
3625-3635 Peterson Way | Acquired below-mark lease intangible
Acquired Finite-Lived Intangible Assets [Line Items]
Period from April 22, 2016 through December 31, 2016		(589)
2,017		(884)
2,018		(884)
2,019		(884)
2,020		$ (884)

Deferred Charges (Details)

Deferred Charges (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred Charges [Abstract]
Leasing costs, including lease related intangibles	$ 1,132,092	$ 1,123,105
Financing costs	6,094	6,094
Deferred charges, gross	1,138,186	1,129,199
Less: Accumulated amortization	(452,023)	(424,332)
Deferred charges, total	$ 686,163	$ 704,867

Deferred Charges Narrative (Det

Deferred Charges Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Entity Information [Line Items]
Deferred Finance Costs, Net	$ 2,358
Mortgages [Member]
Entity Information [Line Items]
Deferred Finance Costs, Net	2,400	$ 3,500
Unsecured Debt [Member]
Entity Information [Line Items]
Deferred Finance Costs, Net	35,300	24,500
Line of Credit [Member]
Entity Information [Line Items]
Deferred Finance Costs, Net	$ 1,900	$ 3,100

Deferred Charges Schedule of Ac

Deferred Charges Schedule of Acquired In-Place Lease Intangibles (Details) $ in Thousands	Dec. 31, 2016USD ($)
Deferred Charges [Abstract]
2,017	$ 37,547
2,018	32,831
2,019	26,556
2,020	13,885
2,021	$ 8,365

Investments in Unconsolidated61

Investments in Unconsolidated Joint Ventures (Investments in Unconsolidated Joint Ventures) (Details) $ in Thousands		12 Months Ended
		Dec. 31, 2016USD ($)ft²Land_ParcelsBuildingspayments	Oct. 20, 2016	Dec. 31, 2015USD ($)
Schedule of Equity Method Investments [Line Items]
Other Liabilities		$ 450,821		$ 483,601
Investments in unconsolidated joint ventures		775,198		235,224
Investments In Affiliates Subsidiaries Associates And Joint Ventures net	[1]	753,111		210,023
Unconsolidated Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Other Liabilities		$ 22,100		25,200
Square 407 Limited Partnership [Member]
Schedule of Equity Method Investments [Line Items]
Properties		Market Square North
Ownership Percentage		50.00%
Other Liabilities	[1]	$ 8,134		9,951
BP/CRF Metropolitan Square LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		Metropolitan Square
Ownership Percentage	[2]	20.00%
Investments in unconsolidated joint ventures	[1]	$ 2,004		9,179
ownership interest sold (percent)			31.00%
BP/CRF 901 New York Avenue LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		901 New York Avenue
Ownership Percentage	[3]	25.00%
Other Liabilities	[1]	$ 10,564		11,958
WP Project Developer LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		Wisconsin Place Land and Infrastructure
Ownership Percentage	[4]	33.30%
Investments in unconsolidated joint ventures	[1]	$ 41,605		43,524
Annapolis Junction NFM, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		Annapolis Junction
Ownership Percentage	[5]	50.00%
Investments in unconsolidated joint ventures	[1]	$ 20,539		29,009
Number of real estate properties | Buildings		4
Parcels of undeveloped land | Land_Parcels		2
540 Madison Venture LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		540 Madison Avenue
Ownership Percentage		60.00%
Investments in unconsolidated joint ventures	[1]	$ 67,816		68,983
500 North Capitol LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		500 North Capitol Street, NW
Ownership Percentage		30.00%
Other Liabilities	[1]	$ 3,389		3,292
501 K Street LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		1001 6th Street
Ownership Percentage	[6]	50.00%
Investments in unconsolidated joint ventures	[1]	$ 42,528		42,584
Potential additonal payments to joint venture partner | payments		2
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]
Properties		The Hub on Causeway - Podium
Ownership Percentage		50.00%
Investments in unconsolidated joint ventures	[1]	$ 29,869		18,508
Residential Tower Developer LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		The Hub on Causeway - Residential
Ownership Percentage		50.00%
Investments in unconsolidated joint ventures	[1]	$ 20,803
Hotel Tower Developer LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		The Hub on Causeway - Hotel
Ownership Percentage		50.00%
Investments in unconsolidated joint ventures	[1]	$ 933
Entity Owning Land And Infrastructure Of Project [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage		33.30%
1265 Main Office JV LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		1265 Main Street
Ownership Percentage		50.00%
Investments in unconsolidated joint ventures	[1]	$ 4,779		11,916
BNY Tower Holdings LLC [Member]
Schedule of Equity Method Investments [Line Items]
Properties		Dock 72 at the Brooklyn Navy Yard
Ownership Percentage	[7]	50.00%
Investments in unconsolidated joint ventures	[1]	$ 33,699		$ 11,521
CA-Colorado Center Limited Partnership [Member]
Schedule of Equity Method Investments [Line Items]
Properties		Colorado Center
Ownership Percentage		49.80%
Investments in unconsolidated joint ventures	[1]	$ 510,623
[1]	Investments with deficit balances aggregating approximately $22.1 million and $25.2 million at December 31, 2016 and 2015, respectively, have been reflected within Other Liabilities in the Company’s Consolidated Balance Sheets.
[2]	On October 20, 2016, the Company sold a 31% ownership interest in this joint venture.
[3]	The Company’s economic ownership has increased based on the achievement of certain return thresholds.
[4]	The Company’s wholly-owned entity that owns the office component of the project also owns a 33.3% interest in the entity owning the land, parking garage and infrastructure of the project.
[5]	The joint venture owns four in-service buildings and two undeveloped land parcels
[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).

Investments in Unconsolidated62

Investments in Unconsolidated Joint Ventures (Balance Sheets of the Unconsolidated Joint Ventures) (Details) - USD ($) $ in Thousands		Dec. 31, 2016	Dec. 31, 2015
ASSETS
Real estate and development in process, net		$ 15,925,028	$ 15,555,641
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Mortgage and notes payable, net		2,063,087	3,435,242
Other Liabilities		450,821	483,601
Total liabilities and equity / capital		18,851,643	18,351,486
Carying value of the Company's investment in unconsolidated joint ventures		775,198	235,224
Unconsolidated Joint Ventures [Member]
ASSETS
Real estate and development in process, net		1,519,217	1,072,412
Other assets		297,263	252,285
Total assets		1,816,480	1,324,697
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Mortgage and notes payable, net		865,665	830,125
Other Liabilities		67,167	44,549
Members'/Partners' equity		883,648	450,023
Total liabilities and equity / capital		1,816,480	1,324,697
Company's share of equity		450,662	237,070
Basis differentials	[1]	302,449	(27,047)
Carying value of the Company's investment in unconsolidated joint ventures	[2]	753,111	210,023
Colorado Center [Member]
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Basis differentials		328,800
Unconsolidated Joint Ventures [Member]
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Other Liabilities		$ 22,100	$ 25,200
[1]	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 December 31, 2016, there is an aggregate basis differential of approximately $328.8 million 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.
[2]	Investments with deficit balances aggregating approximately $22.1 million and $25.2 million at December 31, 2016 and 2015, respectively, have been reflected within Other Liabilities in the Company’s Consolidated Balance Sheets.

Investments in Unconsolidated63

Investments in Unconsolidated Joint Ventures (Statements of Operations of the Joint Ventures) (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Total revenue		$ 636,061	$ 625,228	$ 623,546	$ 665,985	$ 624,240	$ 629,884	$ 618,221	$ 618,476	$ 2,550,820		$ 2,490,821		$ 2,396,998
Expenses
Depreciation and amortization										694,403		639,542		628,573
Total expenses										1,725,036		1,641,456		1,595,176
Operating income										825,784		849,365		801,822
Other income (expense)
Interest expense										(412,849)		(432,196)		(455,743)
Net income										569,977		799,918		526,057
Income from unconsolidated joint ventures										8,074		22,770		12,769
Gain on sale of investment in unconsolidated joint venture										59,370		0		0
Straight-line rent adjustments										31,700		80,000		63,100
Mortgage and notes payable, net		2,063,087				3,435,242				2,063,087		3,435,242
Above and below market rent adjustments, net										30,200		35,900		48,300
Gain on sale of investment in unconsolidated joint venture										55,707		0		0
Unconsolidated Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Total revenue	[1]									177,182		155,642		158,161
Expenses
Operating										76,741		65,093		62,974
Depreciation and amortization										44,989		36,057		37,041
Total expenses										121,730		101,150		100,015
Operating income										55,452		54,492		58,146
Other income (expense)
Interest expense										(34,016)		(32,176)		(31,896)
Net income										21,436		22,316		26,250
Company's share of net income										9,873		22,031	[2]	11,913
Basis differential										(1,799)	[3]	739		856
Income from unconsolidated joint ventures										8,074		22,770		12,769
Straight-line rent adjustments										18,100		3,900		$ 3,000
Mortgage and notes payable, net		$ 865,665				830,125				865,665		830,125
BP/CRF 901 New York Avenue LLC [Member]
Other income (expense)
Mortgage and notes payable, net						$ 225,000						225,000
Gain on sale of investment in unconsolidated joint venture												$ 24,500
Colorado Center [Member]
Other income (expense)
Straight-line rent adjustments										1,400
Above and below market rent adjustments, net										$ (900)
[1]	Includes straight-line rent adjustments of approximately $18.1 million, $3.9 million and $3.0 million for the years ended December 31, 2016, 2015 and 2014, respectively.
[2]	During the year ended December 31, 2015, the Company received a distribution of approximately $24.5 million, which was generated from the excess loan proceeds from the refinancing of 901 New York Avenue’s mortgage loan to a new 10-year mortgage loan totaling $225.0 million. The Company’s allocation of income and distributions for the year ended December 31, 2015 was not proportionate to its nominal ownership interest as a result of the achievement of specified investment return thresholds, as provided for in the joint venture agreement.
[3]	Includes the Company’s share of straight-line rent adjustments of approximately $1.4 million and net below-market rent adjustments of approximately $0.9 million for the year ended December 31, 2016.

Investment in unconsolidated Jo

Investment in unconsolidated Joint Ventures (Narrative) (Details)		Dec. 19, 2016USD ($)ft²yr	Dec. 07, 2016USD ($)ft²yr	Nov. 28, 2016USD ($)yr	Nov. 15, 2016USD ($)ft²	Oct. 20, 2016USD ($)ft²	Jul. 01, 2016USD ($)ft²aVehiclesBuildings	Apr. 11, 2016USD ($)ft²yr	Dec. 31, 2016USD ($)	Oct. 16, 2016	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 08, 2016USD ($)	Nov. 28, 2016ft²	Nov. 28, 2016apartments	Nov. 28, 2016floor	Oct. 21, 2016	Oct. 01, 2016ft²
Schedule of Equity Method Investments [Line Items]
Mortgage and notes payable, net									$ 2,063,087,000		$ 2,063,087,000	$ 3,435,242,000
Payments to Acquire Equity Method Investments											575,795,000	38,207,000	$ 52,052,000
Proceeds from sale of investment in unconsolidated joint venture											55,707,000	0	0
Gain on sales of real estate											59,370,000	0	0
Gains (losses) from early extinguishments of debt											(371,000)	(22,040,000)	(10,633,000)
Repayments of Secured Debt											$ 1,326,865,000	$ 54,801,000	$ 87,758,000
Metropolitian Square [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage						51.00%												20.00%
Net Rentable Area | ft²						607,000
Contractual Sales Price						$ 282,400,000
Carrying Value of Debt Assumed in Sale						133,400,000
Payments for Leasing Costs						14,200,000
Proceeds from sale of investment in unconsolidated joint venture						58,200,000
Gain on sales of real estate						$ 59,400,000
1265 Main Street [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage																			50.00%
Net Rentable Area | ft²																			115,000
1265 Main Office JV LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage									50.00%		50.00%
Annapolis Junction Building Eight [Member]
Schedule of Equity Method Investments [Line Items]
Net Rentable Area | ft²			126,000
Debt Instrument, Basis Spread on Variable Rate			1.50%
Construction Loan			$ 15,100,000
Number of extensions			2
Extension Option (in years) | yr			1
Annapolis Junction Building Seven and Eight [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage			50.00%
Mortgage and notes payable, net			$ 36,700,000
Debt Instrument, Basis Spread on Variable Rate			2.35%
Number of extensions			3
Extension Option (in years) | yr			1
Mortgage note borrowing capacity, maximum			$ 42,000,000
Annapolis Junction Building Seven [Member]
Schedule of Equity Method Investments [Line Items]
Net Rentable Area | ft²			127,000
Debt Instrument, Basis Spread on Variable Rate			1.65%
Construction Loan			$ 21,600,000
Number of extensions			1
Extension Option (in years) | yr			1
Annapolis Junction Building Six [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage					50.00%
Net Rentable Area | ft²					119,000
Construction Loan Facility Borrowing Capacity					$ 15,400,000
Debt Instrument, Basis Spread on Variable Rate					2.25%
Construction Loan					$ 12,900,000
The Hub on causeway - Hotel [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage				50.00%
Contribution of Property				$ 700,000
Air rights lease (in years) | yr				99
Payments to Acquire Equity Method Investments				$ 6,700,000
The Hub on Causeway - Residential [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage				50.00%
Payments and improvements for equity method investments				$ 17,700,000
Net Rentable Area | ft²															320,000
Payments to Acquire Equity Method Investments				$ 6,500,000
Number of apartment units																440	40
Annapolis Junction NFM, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage	[1]								50.00%		50.00%
Dock 72 at Brooklyn Navy Yard [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage		50.00%
Net Rentable Area | ft²		670,000
Construction Loan Facility Borrowing Capacity		$ 250,000,000
Debt Instrument, Basis Spread on Variable Rate		2.25%
Number of extensions		2
Extension Option (in years) | yr		1
Construction facilty, amount outstanding									$ 0		$ 0
joint venture partner [Member] | Metropolitian Square [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage						49.00%												80.00%
joint venture partner [Member] | The Hub on causeway - Hotel [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage				50.00%
Payments to Acquire Equity Method Investments				$ 7,400,000
joint venture partner [Member] | The Hub on Causeway - Residential [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage				50.00%
Payments to Acquire Equity Method Investments				$ 24,200,000
Secured Debt [Member] | Annapolis Junction Buidling One [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage								50.00%
Mortgage and notes payable, net								$ 39,600,000
Net Rentable Area | ft²								118,000
Debt Instrument, Basis Spread on Variable Rate									5.75%	1.75%
Number of extensions								1
Extension Option (in years) | yr								3
Secured Debt [Member] | 1265 Main Street [Member]
Schedule of Equity Method Investments [Line Items]
Coupon/Stated Rate														3.77%
Mortgage Loans on Real Estate, Face Amount of Mortgages														$ 40,400,000
Colorado Center [Member] | Colorado Center [Member]
Schedule of Equity Method Investments [Line Items]
Ownership Percentage							49.80%
Aggregate purchase price							$ 511,100,000
Net Rentable Area | ft²							1,184,000
Net assets							$ 503,600,000
number of buildings | Buildings							6
Land acquired (in acres) | a							15
Vehicles In Structured Parking | Vehicles							3,100
[1]	The joint venture owns four in-service buildings and two undeveloped land parcels

Investments in Unconsolidated65

Investments in Unconsolidated Joint Ventures Business Acquisition Purchase Price table (Details) - Colorado Center [Member] - Colorado Center [Member] $ in Thousands	Jul. 01, 2016USD ($)
Schedule of Equity Method Investments [Line Items]
Land and improvements	$ 189,597
Site improvements	9,050
Building and improvements	259,592
Tenant Improvements	17,234
In-place lease Intangibles	43,157
Above-market lease intangible	819
Below-market lease intangible	(16,461)
Net assets	$ 502,988

Mortgage Notes Payable Schedu66

Mortgage Notes Payable Schedule Of Aggregate Principal Payments On Mortgage Notes (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Mortgage Notes Payable [Abstract]
2,017	$ 1,317,654
2,018	18,633
2,019	19,670
2,020	20,766
2,021	40,182
Thereafter	614,710
Total	2,031,615
Unamortized balance of historical fair value adjustments	33,830
Deferred finance costs, net	(2,358)
Total carrying value of mortgage notes payable, net	$ 2,063,087	$ 3,435,242

Mortgage Notes Payable (Narrati

Mortgage Notes Payable (Narrative) (Details) $ in Thousands	Sep. 01, 2016USD ($)	Apr. 11, 2016USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Mortgage Notes Payable [Line Items]
Mortgage notes payable, net			$ 2,063,087	$ 3,435,242
Mezzanine notes payable			$ 307,093	308,482
Final maturity date of mortgage notes			Apr. 10, 2022
Repayments of mortgage notes payable			$ 1,326,865	54,801	$ 87,758
Gains (losses) from early extinguishments of debt			$ (371)	$ (22,040)	(10,633)
Number Of Mortgage Loans Accounted For Fair Value			1	2
Outstanding balance of mortgage loans accounted for at fair value			$ 1,300,000	$ 1,500,000
Interest Expense Decrease Due To Recording Mortgage Loans At Fair Value			46,400	55,000	52,500
Cumulative Liability Related to the Fair Value of Debt Adjustment			33,800	80,200
Unamortized balance of historical fair value adjustments			33,830
Interest expense			$ 412,849	432,196	$ 455,743
Minimum [Member]
Mortgage Notes Payable [Line Items]
Number Real Estate Assets Used For Mortgage Loan Collateral			1
Fixed Rate Mortgages [Member]
Mortgage Notes Payable [Line Items]
Mortgage notes payable, net			$ 2,100,000	$ 3,400,000
Contractual interest rate range, minimum			4.75%	4.75%
Contractual interest rate range, maximum			7.69%	7.69%
Contractual interest rate, weighted average interest rate			5.59%	5.69%
Variable Rate Mortgages [Member]
Mortgage Notes Payable [Line Items]
Number of variable rate mortgage loans			0	0
London Interbank Offered Rate			0.77%	0.43%
Fountain Square [Member] | Secured Debt [Member]
Mortgage Notes Payable [Line Items]
Repayments of mortgage notes payable		$ 211,300
Interest at a fixed rate		5.71%
599 Lexington Avenue | Secured Debt [Member]
Mortgage Notes Payable [Line Items]
Repayments of mortgage notes payable	$ 750,000
Interest at a fixed rate	5.57%
Effective Rate	5.41%
Gains (losses) from early extinguishments of debt	$ 400
Embarcadero Center Four [Member] | Secured Debt [Member]
Mortgage Notes Payable [Line Items]
Repayments of mortgage notes payable	$ 344,800
Interest at a fixed rate	6.10%
Effective Rate	7.02%
Gains (losses) from early extinguishments of debt	$ (700)
Consolidated Properties [Member] | 767 Fifth Avenue (the General Motors Building)
Mortgage Notes Payable [Line Items]
Ownership Percentage by Parent			60.00%
Mortgage notes payable, net			$ 1,300,000
Mezzanine notes payable			$ 306,000
Interest at a fixed rate			5.96%

Derivative and Hedging Instru68

Derivative and Hedging Instruments (Details) $ in Thousands	Aug. 17, 2016USD ($)	Jan. 06, 2016USD ($)swaps	Dec. 31, 2016USD ($)yrswaps	Dec. 31, 2015USD ($)yr	Dec. 31, 2014USD ($)
Derivative [Line Items]
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months			$ (500)
Other liabilities			(106,022)	$ (34,005)	$ (57,873)
Losses from interest rate contracts			$ (140)	0	0
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount				$ 950,000
Boston Properties Limited Partnership | Interest Rate Swap [Member]
Derivative [Line Items]
Number of interest rate swap agreements entered into | swaps			17
Term of anticipated mortgage loan (in years) | yr			10	10
Derivative, Average Fixed Interest Rate				2.423%
Derivative, Notional Amount				$ 550,000
Maximum period of hedging exposure to the variability in future cash flows for forecasted transactions (in years) | yr			10
767 Fifth Partners LLC [Member]
Derivative [Line Items]
Ownership Percentage by Parent			60.00%
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Number of interest rate swap agreements entered into | swaps		2	16
Term of anticipated mortgage loan (in years) | yr			10
Derivative, Average Fixed Interest Rate			2.619%
Derivative, Notional Amount		$ 50,000	$ 450,000	400,000
Maximum period of hedging exposure to the variability in future cash flows for forecasted transactions (in years) | yr			10
Derivative, Net Liability Position, Aggregate Fair Value			$ 8,700
Assets Needed for Immediate Settlement, Aggregate Fair Value			8,700
Derivative Instruments, Loss Recognized in Other Liabilities			8,800
Derivative Instruments, Gain Recognized in Prepaid Expenses and Other Assets			500
Boston Properties Limited Partnership
Derivative [Line Items]
Other liabilities			(106,022)	(34,005)	(57,873)
Losses from interest rate contracts			$ (140)	$ 0	$ 0
Boston Properties Limited Partnership | Interest Rate Swap [Member]
Derivative [Line Items]
Other liabilities	$ 49,300
Losses from interest rate contracts	(100)
Derivative Instruments, Loss Reclassified from Accumulated OCI into Income, Effective Portion	49,200
Derivative instrument, yearly amount reclassed to interest expense	$ 4,900
Unsecured Senior Note 3.495% | Senior Notes [Member] | Boston Properties Limited Partnership
Derivative [Line Items]
Coupon/Stated Rate	2.75%		2.75%

Derivative and Hedging Instru69

Derivative and Hedging Instruments Derivative Instrument and Hedging Activities Notional Table (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jan. 06, 2016
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair Value	$ (47,144)	$ (10,302)	$ 0
Interest Rate Swap [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount		950,000
Fair Value		(10,302)
Boston Properties Limited Partnership | Interest Rate Swap [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount		550,000
Fair Value		(4,231)
Boston Properties Limited Partnership | Interest Rate Swap [Member] | Interest Rate Swap Range 2.129% - 2.325% [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Asset, Notional Amount		$ 150,000
Derivative, Lower Fixed Interest Rate Range		2.129%
Derivative, Higher Fixed Interest Rate Range		2.325%
Fair Value		$ 1,188
Boston Properties Limited Partnership | Interest Rate Swap [Member] | Interest Rate Swap Range 2.348% - 2.571% [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Liability, Notional Amount		$ 400,000
Derivative, Lower Fixed Interest Rate Range		2.348%
Derivative, Higher Fixed Interest Rate Range		2.571%
Fair Value		$ (5,419)
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative, Notional Amount	450,000	400,000		$ 50,000
Fair Value	(8,264)	(6,071)
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member] | Interest Rate Swap Range 2.336% - 2.430% [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Asset, Notional Amount		$ 150,000
Derivative, Lower Fixed Interest Rate Range		2.336%
Derivative, Higher Fixed Interest Rate Range		2.43%
Fair Value		$ 1,176
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member] | Interest Rate Swap Range 2.677% - 2.950% [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Liability, Notional Amount		$ 250,000
Derivative, Lower Fixed Interest Rate Range		2.677%
Derivative, Higher Fixed Interest Rate Range		2.95%
Fair Value		$ (7,247)
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member] | Interest Rate Swap Range 2.418% - 2.950% [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Liability, Notional Amount	$ 350,000
Derivative, Lower Fixed Interest Rate Range	2.418%
Derivative, Higher Fixed Interest Rate Range	2.95%
Fair Value	$ (8,773)
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member] | Interest Rate Swap Range 2.366% to 2.388% [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Derivative Asset, Notional Amount	$ 100,000
Derivative, Lower Fixed Interest Rate Range	2.336%
Derivative, Higher Fixed Interest Rate Range	2.388%
Fair Value	$ 509

Derivative and Hedging Instru70

Derivative and Hedging Instruments Derivative Instruments and Hedging Activities Gain or Loss Recognized Related to Cash Flow Hedges (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014
Derivative [Line Items]
Losses from interest rate contracts	$ (140)		$ 0	$ 0
Amount of loss related to the effective portion recognized in other comprehensive loss	(47,144)		(10,302)	0
Amount of loss related to the portion subsequently reclassified to earnings	(3,751)	[1]	(2,510)	(2,508)
Amount of loss related to the ineffective portion and amount excluded from effectiveness testing	(140)		$ 0	$ 0
Prior hedge program [Member]
Derivative [Line Items]
Losses from interest rate contracts	$ (200)
[1]	During the year ended December 31, 2016, the Company accelerated the reclassification of amounts in other comprehensive loss to earnings as a result of the hedged forecasted transactions becoming probable not to occur. The accelerated amounts were a loss of approximately $0.2 million and are included in the table above.

Derivative and Hedging Instru71

Derivative and Hedging Instruments Derivative Instruments and Hedging Activities Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Beginning Balance		$ (14,114)	$ (9,304)	$ (11,556)
Effective portion of interest rate contracts		(47,144)	(10,302)	0
Amortization of interest rate contracts	[1]	3,751	2,510	2,508
Other comprehensive (income) loss attributable to noncontrolling interests		5,256	2,982	(256)
Ending Balance		(52,251)	(14,114)	(9,304)
Boston Properties Limited Partnership
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Beginning Balance		(18,337)	(12,973)	(15,481)
Effective portion of interest rate contracts		(47,144)	(10,302)	0
Amortization of interest rate contracts	[2]	3,751	2,510	2,508
Other comprehensive loss attributable to noncontrolling interests in property partnership		877	2,428
Ending Balance		$ (60,853)	$ (18,337)	$ (12,973)
[1]	Amounts reclassified from comprehensive income primarily to interest expense within Boston Properties, Inc.’s Consolidated Statements of Operations
[2]	Amounts reclassified from comprehensive income primarily to interest expense within Boston Properties Limited Partnership's Consolidated Statements of Operations.

Unsecured Senior Notes Schedule

Unsecured Senior Notes Schedule of Unsecured Senior Notes (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016		Aug. 17, 2016	Jan. 20, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Deferred finance costs, net		$ (2,358)
Total		7,245,953				$ 5,264,819
Boston Properties Limited Partnership
Debt Instrument [Line Items]
Deferred finance costs, net		2,400
Total		7,245,953				$ 5,264,819
Boston Properties Limited Partnership | Senior Notes [Member]
Debt Instrument [Line Items]
Principal Amount		7,300,000
Net unamortized discount		(18,783)
Deferred finance costs, net		(35,264)
Total		$ 7,245,953
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Notes 5.967%
Debt Instrument [Line Items]
Coupon/Stated Rate		5.875%
Effective Rate	[1]	5.967%
Principal Amount		$ 700,000
Maturity date	[2]	Oct. 15, 2019
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Notes 5.708%
Debt Instrument [Line Items]
Coupon/Stated Rate		5.625%
Effective Rate	[1]	5.708%
Principal Amount		$ 700,000
Maturity date	[2]	Nov. 15, 2020
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Notes 4.289%
Debt Instrument [Line Items]
Coupon/Stated Rate		4.125%
Effective Rate	[1]	4.289%
Principal Amount		$ 850,000
Maturity date	[2]	May 15, 2021
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Notes 3.853%
Debt Instrument [Line Items]
Coupon/Stated Rate		3.70%
Effective Rate	[1]	3.853%
Principal Amount		$ 850,000
Maturity date	[2]	Nov. 15, 2018
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Notes 3.954%
Debt Instrument [Line Items]
Coupon/Stated Rate		3.85%
Effective Rate	[1]	3.954%
Principal Amount		$ 1,000,000
Maturity date	[2]	Feb. 1, 2023
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Notes 3.279%
Debt Instrument [Line Items]
Coupon/Stated Rate		3.125%
Effective Rate	[1]	3.279%
Principal Amount		$ 500,000
Maturity date	[2]	Sep. 1, 2023
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Notes 3.916%
Debt Instrument [Line Items]
Coupon/Stated Rate		3.80%
Effective Rate	[1]	3.916%
Principal Amount		$ 700,000
Maturity date	[2]	Feb. 1, 2024
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Note 3.766%
Debt Instrument [Line Items]
Coupon/Stated Rate		3.65%			3.65%
Effective Rate		3.766%	[1]		3.766%
Principal Amount		$ 1,000,000			$ 1,000,000
Maturity date	[2]	Feb. 1, 2026
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Note 3.495%
Debt Instrument [Line Items]
Coupon/Stated Rate		2.75%		2.75%
Effective Rate		3.495%	[1]	3.495%
Principal Amount		$ 1,000,000		$ 1,000,000
Maturity date	[2]	Oct. 1, 2026
[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 Unsecure

Unsecured Senior Notes Unsecured Senior Notes (Narrative) (Details) - USD ($) $ in Thousands	Aug. 17, 2016	Jan. 20, 2016	Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Maximum Secured Debt Leverage Ratio			55.00%
Proceeds from unsecured senior notes			$ 1,989,790		$ 0	$ 0
Senior Notes [Member]
Debt Instrument [Line Items]
Maximum Leverage Ratio			60.00%
Maximum Secured Debt Leverage Ratio			50.00%
Minimum Interest Coverage Ratio			1.50
Minimum Unencumbered Asset Value Percentage Of Unsecured Debt			150.00%
Boston Properties Limited Partnership
Debt Instrument [Line Items]
Proceeds from unsecured senior notes			$ 1,989,790		$ 0	$ 0
Boston Properties Limited Partnership | Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 7,300,000
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Note 3.766%
Debt Instrument [Line Items]
Coupon/Stated Rate		3.65%	3.65%
Senior Notes Pricing		99.708%
Effective Rate		3.766%	3.766%	[1]
Proceeds from unsecured senior notes		$ 988,900
Long-term Debt, Gross		$ 1,000,000	$ 1,000,000
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Note 3.495%
Debt Instrument [Line Items]
Coupon/Stated Rate	2.75%		2.75%
Senior Notes Pricing	99.271%
Effective Rate	3.495%		3.495%	[1]
Proceeds from unsecured senior notes	$ 984,700
Long-term Debt, Gross	$ 1,000,000		$ 1,000,000
[1]	Yield on issuance date including the effects of discounts on the notes, settlements of interest rate contracts and the amortization of financing costs.

Unsecured Line of Credit (Detai

Unsecured Line of Credit (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)yrmo	Dec. 31, 2015USD ($)
Line of Credit Facility [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 1,000,000
Line of Credit Facility, Expiration Date	Jul. 26, 2018
Line of Credit Facility, Frequency of Commitment Fee Payment	quarterly
Line of Credit Facility, Amount Outstanding	$ 0	$ 0
Leverage Ratio, Maximum	60.00%
Leverage Ratio Maximum Increasing Limit	65.00%
Leverage Ratio Reduction Limit	60.00%
Leverage Ratio Reduction Period, Years | yr	1
Maximum Secured Debt Leverage Ratio	55.00%
Fixed Charge Coverage Ratio Minimum.	1.40
Maximum Unsecured Debt Leverage Ratio	60.00%
Unsecured Debt Leverage Ratio Maximum Increasing Limit	65.00%
Unsecured Debt Leverage Ratio Reduction Limit	60.00%
Unsecured Debt Leverage Ratio Reduction Period, Years | yr	1
Unsecured Debt Interest Coverage Ratio Minimum.	1.75
Alternative Base Interest Rate Calculation [Member]
Line of Credit Facility [Line Items]
Amount added to Federal Funds Rate to Calculate Interest Rate	0.50%
LIBOR Period Used to Calculate Interest Rate (in months) | mo	1
Amount added to LIBOR to Calculate Interest Rate	1.00%
Maximum [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 1,500,000
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.35%
Maximum [Member] | Interest Rate Based on LIBOR or CDOR [Member]
Line of Credit Facility [Line Items]
Margin added to Calculated Interest Rate	1.70%
Maximum [Member] | Alternative Base Interest Rate Calculation [Member]
Line of Credit Facility [Line Items]
Margin added to Calculated Interest Rate	0.70%
Minimum [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.125%
Minimum [Member] | Interest Rate Based on LIBOR or CDOR [Member]
Line of Credit Facility [Line Items]
Margin added to Calculated Interest Rate	0.925%
Minimum [Member] | Alternative Base Interest Rate Calculation [Member]
Line of Credit Facility [Line Items]
Margin added to Calculated Interest Rate	0.00%
Rate Based on Current Credit Rating [Member]
Line of Credit Facility [Line Items]
Line Of Credit Facility Extension Fee	0.15%
Rate Based on Current Credit Rating [Member] | Interest Rate Based on LIBOR or CDOR [Member]
Line of Credit Facility [Line Items]
Margin added to Calculated Interest Rate	1.00%
Rate Based on Current Credit Rating [Member] | Alternative Base Interest Rate Calculation [Member]
Line of Credit Facility [Line Items]
Margin added to Calculated Interest Rate	0.00%

Commitments And Contingencies (

Commitments And Contingencies (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2009	Jul. 05, 2016	Sep. 09, 2015	Mar. 11, 2015	Sep. 18, 2014	Jan. 10, 2014
Commitments And Contingencies [Line Items]
Letter of credit and performance obligations	$ 12.3
Property insurance program per occurrence limits	1,000
Per occurrence limit for NBCR Coverage	1,000
Value of program trigger	$ 120
Coinsurance of program trigger	16.00%
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	$ 170
Annual aggregate limit of the earthquake insurance which covers San Francisco and Los Angeles regions	170
Amount of earthquake insurance provided by IXP, LLC as direct insurer San Francisco and Los Angeles	20
Earthquake Coverage Included In Builders Risk Policy For Below Grade improvements for Salesforce Tower	60
Operating partnership guarantee to cover liabilities of IXP	20
767 Venture, LLC [Member]
Commitments And Contingencies [Line Items]
Maximum funding obligation	41.7
Property insurance program per occurrence limits	1,625
601 Lexington Avenue
Commitments And Contingencies [Line Items]
Coverage For Acts Of Terrorism Under TRIA Covered in Excess of Amount Covered by IXP	250
Lehman [Member]
Commitments And Contingencies [Line Items]
Bankruptcy claim, amount filed by general creditor		$ 45.3
Bankruptcy claim amount allowed by court to creditor	$ 28						$ 45.2
Bankruptcy Claims, Amount of Claims Settled			$ 1.4	$ 3.6	$ 4.5	$ 7.7
767 Fifth Partners LLC [Member]
Commitments And Contingencies [Line Items]
Ownership Percentage by Parent	60.00%

Noncontrolling Interests (Narra

Noncontrolling Interests (Narrative) (Details)	Dec. 31, 2016shares
Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Operating Partnership (OP) Units (in shares)	17,079,511
Long-Term Incentive Plan (LTIP) Units (in shares)	904,588
Boston Properties Limited Partnership | 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)	166,629
Boston Properties Limited Partnership | MYLTIP 2013
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2013 MYLTIP	93,928
Boston Properties Limited Partnership | MYLTIP 2014
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2014 MYLTIPs	474,415
Boston Properties Limited Partnership | MYLTIP 2015 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2015 MYLTIPS	367,218
Boston Properties Limited Partnership | MYLTIP 2016 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2016 MYLTIP	473,360

Noncontrolling Interests (Redee

Noncontrolling Interests (Redeemable Preferred Units) (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	Jun. 25, 2015	May 12, 2014	Dec. 31, 2014	Nov. 05, 2014	Oct. 16, 2014	Jul. 03, 2014	May 19, 2014
Series Two Preferred Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Units converted (in shares)			666,116
Series Two Preferred Units [Member] | Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Liquidation preference percentage		6.00%
Operating Units liquidation preference (in dollars per share)		$ 38.10
OP Units for each Preferred Unit (in shares)		1.312336
Units converted (in shares)		666,116
Series Two Preferred Units On Converted Basis		874,168
Preferred Units Liquidation Preference		$ 50
Series Four Preferred Units [Member] | Noncontrolling Interests [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Series Four Preferred Units Redeemed	12,667
Series Four Preferred Units Released from Escrow					27,773		319,687
Redemption of Series Four Preferred Units	$ 0.6			$ 1.4		$ 16
Series Four Preferred Units Annual Dividend Payable Rate	2.00%
Preferred Units Liquidation Preference	$ 50
OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Units converted (in shares)			874,168

Noncontrolling Interests (Red78

Noncontrolling Interests (Redeemable Preferred Units) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Net Loss			$ (7)	$ (603)
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Net income		$ 0	6	1,023
Redemption of redeemable preferred units (Series Four Preferred Units)		0	(633)	(17,373)
Conversion of redeemable preferred units (Series Two Preferred Units) to common units				33,306
Conversion of redeemable partnership units		0	0	$ 0
Series Two Preferred Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Units converted (in shares)				666,116
Redeemable Preferred Units [Member]
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning Balance		0	633	$ 51,312
Net income			6	1,023
Distributions			(6)	(1,023)
Redemption of redeemable preferred units (Series Four Preferred Units)			(633)	(17,373)
Conversion of redeemable preferred units (Series Two Preferred Units) to common units				(33,306)
Ending Balance			0	$ 633
OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Units converted (in shares)				874,168
Boston Properties Limited Partnership
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Net income		0	6	$ 1,023
Redemption of redeemable preferred units (Series Four Preferred Units)		0	(633)	(17,373)
Conversion of redeemable partnership units		(6,461)	(14,343)	(2,700)
Redeemable Preferred Units [Member] | Boston Properties Limited Partnership
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning Balance		$ 0	633	105,746
Net income			6	1,023
Distributions			(6)	(1,023)
Redemption of redeemable preferred units (Series Four Preferred Units)			(633)	(17,373)
Conversion of redeemable partnership units	[1]			(87,740)
Ending Balance			$ 0	$ 633
[1]	Includes the conversion of 666,116 Series Two Preferred Units into 874,168 OP Units during the year ended December 31, 2014

Noncontrolling Interests Redeem

Noncontrolling Interests Redeemable interest in property partnerships (narrative) (Details) - USD ($) $ in Thousands	Sep. 15, 2015	Aug. 06, 2015	Oct. 04, 2012	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Payments for Repurchase of Redeemable Noncontrolling Interest				$ 0	$ 108,499	$ 0
Fountain Square
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Aggregate purchase price			$ 385,000
Debt recorded upon consolidation			$ 211,300
Ownership Percentage	50.00%	50.00%	50.00%
Fixed Price to Acquire Remaining Portion of Joint venture		$ 100,900
Consideration paid			$ 87,000
Ownership Percentage by Parent			50.00%
Future Fixed Price to Acquire Remaining Portion of Joint venture			$ 102,000
Payments for Repurchase of Redeemable Noncontrolling Interest	$ 100,900
Mortgage debt assumed upon acquisition of noncontrolling interest	$ 105,600

Noncontrolling Interests Rede80

Noncontrolling Interests Redeemable Property Partnerships (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning Balance	$ 104,692	$ 99,609
Net Loss	(7)	(603)
Distributions	(2,900)	(6,000)
Adjustment to reflect redeemable partnership units at redemption value	5,128	11,686
Acquisition of interest	(106,913)
Ending Balance	$ 0	$ 104,692

(Common Units) (Narrative) (Det

(Common Units) (Narrative) (Details) $ / shares in Units, $ in Millions	Feb. 04, 2016USD ($)shares	Feb. 06, 2015USD ($)shares	Dec. 31, 2016USD ($)yr$ / sharesshares	Dec. 31, 2015shares	Dec. 31, 2014USD ($)	May 02, 2016shares
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Conversion of LTIP Units to OP Units (in units)						625,043
2012 OPP and 2013 MYLTIP [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Conversion of LTIP Units to OP Units (in units)						32,349
OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
OP Units for redemption (in shares)			190,857	424,236
Redemption of OP units issued on conversion of LTIP Units (in shares)			103,847	65,192
MYLTIP Units distribution as percentage of OP Unit distribution prior to measurement date			10.00%
Restriction on redemption of OP Unit to Common Stock (in years) | yr			1
Redemption of OP Unit equivalence to Common Stock (in shares)			1
Common units of operating partnership if converted value | $			$ 2,300
Closing price of common stock (in dollars per share) | $ / shares			$ 125.78
OPP Units 2011 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Accelerated Compensation Expenses Related To 2011 OPP Units | $					$ 1.2
MYLTIP 2,013
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Final awards percentage of target	109.50%
Value of MYLTIP Awards | $	$ 13.5
MYLTIP Units forfeited	205,762
OPP Units 2012 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Outperformance awards earned | $		$ 32.1
Potential maximum amount of Outperformance Awards earned (percent)		80.00%
Potential Awards Earned | $		$ 40
2012 OPP Units forfeited		174,549
Boston Properties Limited Partnership | MYLTIP 2016 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2016 MYLTIP			473,360
Boston Properties Limited Partnership | MYLTIP 2014
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2014 MYLTIPs			474,415
Boston Properties Limited Partnership | MYLTIP 2015 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2015 MYLTIPS			367,218

Noncontrolling Interests Common

Noncontrolling Interests Common Units Distributions (Details) - $ / shares	Oct. 31, 2016	Jul. 29, 2016	Apr. 29, 2016	Jan. 28, 2016		Dec. 19, 2016
special dividend [Member] | OP Units [Member]
Noncontrolling Interest [Line Items]
Distributions Declared To OP And LTIP Units Per Unit				$ 1.25
Boston Properties Limited Partnership
Noncontrolling Interest [Line Items]
Distributions Declared To OP And LTIP Units Per Unit						$ 0.75
Distributions Declared To MYLTIP Units Per Unit						$ 0.075
Distributions made to OP and LTIP units per unit (in dollars per share)	$ 0.65	$ 0.65	$ 0.65	1.90	[1]
Distributions Made To MYLTIP Units Per Unit	$ 0.065	$ 0.065	$ 0.065	$ 0.065
[1]	Includes a special distribution of $1.25 per unit.

Noncontrolling Interests Rede83

Noncontrolling Interests Redeemable common units of Boston Properties Limited Partnership (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Conversion of redeemable partnership units	$ 0	$ 0	$ 0
Adjustment to reflect redeemable partnership units at redemption value		5,128	11,686
Boston Properties Limited Partnership
Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning Balance	2,286,689	2,310,046	1,710,218
Contributions	31,395	39,030	23,990
Net income	59,260	66,951	50,862
Distributions	(49,087)	(69,447)	(126,948)
Conversion of redeemable partnership units	(6,461)	(14,343)	(2,700)
Unearned compensation	(3,464)	(4,579)	(2,813)
Other Comprehensive Income (Loss),	(4,379)	(554)	256
Adjustment to reflect redeemable partnership units at redemption value	(51,913)	(40,415)	657,181
Ending Balance	$ 2,262,040	$ 2,286,689	$ 2,310,046

Noncontrolling Interests (Prope

Noncontrolling Interests (Property Partnerships) (Narrative) (Details) $ in Thousands	May 12, 2016	Sep. 18, 2015USD ($)ft²	Oct. 30, 2014USD ($)ft²floor	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 10, 2015USD ($)
Noncontrolling Interest [Line Items]
Property partnerships				$ 1,530,647	$ 1,574,400
Proceeds from sales of real estate				122,750	602,600	$ 419,864
Gains on sales of real estate				80,606	375,895	168,039
505 9th Street [Member] | Consolidated Properties [Member]
Noncontrolling Interest [Line Items]
Ownership Percentage by Parent		50.00%
Sale Price Of Sold Property		$ 318,000
Mortgage Loan Related to Property Sales		$ 117,000
Net Rentable Area | ft²		322,000
Proceeds from sales of real estate		$ 194,600
Gains on sales of real estate		199,500
Noncontroling interest for a dissolved entity relcassed to accounts payable and and accrued expenses				200			$ 4,100
Consolidated Entity Excluding Variable Interest Entities (VIE) [Member] | 505 9th Street [Member] | Consolidated Properties [Member]
Noncontrolling Interest [Line Items]
Proceeds from sales of real estate		97,300
Gains on sales of real estate		101,100
Boston Properties Limited Partnership
Noncontrolling Interest [Line Items]
Property partnerships				1,530,647	1,574,400
Proceeds from sales of real estate				122,750	602,600	419,864
Gains on sales of real estate				82,775	$ 377,093	$ 174,686
Boston Properties Limited Partnership | 505 9th Street [Member] | Consolidated Properties [Member]
Noncontrolling Interest [Line Items]
Gains on sales of real estate		$ 199,700
601 Lexington Avenue, Atlantic Wharf Office Building and 100 Federal Street [Member]
Noncontrolling Interest [Line Items]
Sale Price Of Sold Property			$ 1,827,000
Portion allocation to noncontrolling interest based on carrying value of the total equity of the property prior to the sale			849,000
Difference between net cash proceeds received and noncontrolling interest recognized			648,500
Proceeds from sale of an interest in a real estate asset			$ 1,497,000
Ownership Percentage			45.00%
Secured debt			$ 712,900
601 Lexington Avenue | 601 Lexington Avenue, Atlantic Wharf Office Building and 100 Federal Street [Member]
Noncontrolling Interest [Line Items]
Net Rentable Area | ft²			1,669,000
Atlantic Wharf | 601 Lexington Avenue, Atlantic Wharf Office Building and 100 Federal Street [Member]
Noncontrolling Interest [Line Items]
Net Rentable Area | ft²			791,000
100 Federal Street | 601 Lexington Avenue, Atlantic Wharf Office Building and 100 Federal Street [Member]
Noncontrolling Interest [Line Items]
Net Rentable Area | ft²			1,323,000
Office Tower [Member] | 601 Lexington Avenue, Atlantic Wharf Office Building and 100 Federal Street [Member]
Noncontrolling Interest [Line Items]
Number of floors in building | floor			59
Low Rise Building [Member] | 601 Lexington Avenue, Atlantic Wharf Office Building and 100 Federal Street [Member]
Noncontrolling Interest [Line Items]
Number of floors in building | floor			6
Salesforce Tower | Consolidated Properties [Member]
Noncontrolling Interest [Line Items]
Ownership Percentage	5.00%
Portion of project costs covered by a construction loan	50.00%
Portion of costs funded (in percentage)	50.00%
Debt Instrument, Basis Spread on Variable Rate	3.00%
Salesforce Tower | Boston Properties, Inc. [Member] | Consolidated Properties [Member]
Noncontrolling Interest [Line Items]
Costs funded (in percentage)	2.50%
Preferred equity funded				$ 4,300

Noncontrolling Interests noncon

Noncontrolling Interests noncontrolling interests—property partnerships table (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Noncontrolling Interest [Line Items]
Beginning Balance	$ 1,574,400
Capital contributions	11,951	$ 2,705
Dissolution		(4,082)
Net income (loss)	(2,068)	149,855	$ 30,561
Accumulated other comprehensive loss	(5,256)	(2,982)	256
Ending Balance	1,530,647	1,574,400
Property Partnerships Member
Noncontrolling Interest [Line Items]
Beginning Balance	1,574,400	1,602,467	726,132
Capital contributions	10,756	3,758	887,975
Dissolution		(4,082)
Net income (loss)	(2,068)	144,734	19,478
Accumulated other comprehensive loss	(877)	(2,428)
Distributions	(51,564)	(170,049)	(31,118)
Ending Balance	$ 1,530,647	$ 1,574,400	$ 1,602,467

Stockholders' Equity _ Partne86

Stockholders' Equity / Partners' Capital (Details)	12 Months Ended
	Dec. 31, 2016USD ($)yr$ / sharesshares	Dec. 31, 2015$ / sharesshares	Dec. 31, 2014shares	Mar. 27, 2018$ / shares
Class of Stock [Line Items]
General Partners' Capital Account, Units Outstanding (in units)	1,717,743
Limited Partners' Capital Account, Units Outstanding	152,072,432
Common stock, shares outstanding	153,790,175	153,579,966
Shares of Common Stock upon the exercise of options to purchase Common Stock by certain employees	0	11,447	(21,459)
Shares of its Common Stock in connection with the redemption of an equal number of OP Units	190,857	424,236
ATM Program [Member]
Class of Stock [Line Items]
At the market stock offering program, aggregate value of common stock | $	$ 600,000,000
At Market Stock Offering Program Maximum Length Of Program In Years | yr	3
ATM program amount issued | $	$ 0
Series B Cumulative Redeemable Preferred Stock / Unit [Member]
Class of Stock [Line Items]
Preferred stock, shares outstanding	80,000	80,000
Preferred Stock, Dividend Rate, Percentage	5.25%
Series B Liquidation Preference Per Share | $ / shares	$ 2,500	$ 2,500		$ 2,500
Depositary shares of Series B Cumulative Redeemable Preferred [Member]
Class of Stock [Line Items]
Preferred stock, shares outstanding	8,000,000
Series B Liquidation Preference Per Share | $ / shares	$ 25			$ 25
Boston Properties Limited Partnership
Class of Stock [Line Items]
General Partners' Capital Account, Units Outstanding (in units)	1,717,743	1,715,092
Limited Partners' Capital Account, Units Outstanding	152,072,432	151,864,874
Shares of its Common Stock in connection with the redemption of an equal number of OP Units	190,857	424,236	80,246
Boston Properties Limited Partnership | Series B Cumulative Redeemable Preferred Stock / Unit [Member]
Class of Stock [Line Items]
Preferred stock, shares outstanding	80,000	80,000
Series B Liquidation Preference Per Share | $ / shares	$ 2,500	$ 2,500

Stockholders' Equity _ Partne87

Stockholders' Equity / Partners' Capital Dividends / Distributions (Details) - $ / shares	Nov. 15, 2016	Oct. 31, 2016	Aug. 15, 2016	Jul. 29, 2016	May 16, 2016	Apr. 29, 2016	Feb. 16, 2016	Jan. 28, 2016		Dec. 19, 2016	Dec. 31, 2015	Jan. 28, 2015	Dec. 31, 2014
Dividends / Distributions [Line Items]
Special dividend / distribution (per share / common unit amount)								$ 1.25			$ 1.25		$ 4.50
Common Stock / Unit, Dividends / Distributions, Per Share / Unit, Cash Paid		$ 0.65		$ 0.65		$ 0.65		1.90	[1]
Dividends Payable, Amount Per Share / Unit										$ 0.75
Boston Properties Limited Partnership
Dividends / Distributions [Line Items]
Special dividend / distribution (per share / common unit amount)								1.25				$ 4.50
Common Stock / Unit, Dividends / Distributions, Per Share / Unit, Cash Paid		$ 0.65		$ 0.65		$ 0.65		$ 1.90	[1]
Dividends Payable, Amount Per Share / Unit										0.75
Series B Cumulative Redeemable Preferred Stock / Unit [Member]
Dividends / Distributions [Line Items]
Common Stock / Unit, Dividends / Distributions, Per Share / Unit, Cash Paid	$ 32.8125		$ 32.8125		$ 32.8125		$ 32.8125
Dividends Payable, Amount Per Share / Unit										$ 32.8125
[1]	Includes a special dividend/distribution of $1.25 per share/OP Unit and LTIP Unit.

Stockholders' Equity _ Partne88

Stockholders' Equity / Partners' Capital Partners' Capital Changes in Issued and Outstanding Partners' Capital Units (Details) - shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Limited Partners' Capital Account [Line Items]
Units issued to Boston Properties, Inc. related to Common Stock issued in exchange for OP Units	190,857	424,236
Limited Partners' Ending Balance	152,072,432
General Partners' Ending Balance	1,717,743
Boston Properties Limited Partnership
Limited Partners' Capital Account [Line Items]
General Partners' Beginning Balance	1,715,092
Limited Partners Beginning Balance	151,864,874
Partners' Capital Beginning Balance	153,579,966	153,113,945	152,983,101
Units issued to Boston Properties, Inc. related to Common Stock issued under the Employee Stock Purchase Plan	5,695	6,199	6,964
Units issued to Boston Properties, Inc. related to Common Stock issued under the Stock Option and Incentive Plan, net	13,657	35,586	43,634
Units issued to Boston Properties, Inc. related to Common Stock issued in exchange for OP Units	190,857	424,236	80,246
Limited Partners' Ending Balance	152,072,432	151,864,874
Partners' Capital Ending Balance	153,790,175	153,579,966	153,113,945
General Partners' Ending Balance	1,717,743	1,715,092
Boston Properties Limited Partnership | General Partner [Member]
Limited Partners' Capital Account [Line Items]
General Partners' Beginning Balance	1,715,092	1,710,644	1,700,222
Units issued to Boston Properties, Inc. related to Common Stock issued under the Employee Stock Purchase Plan	72	59	555
Units issued to Boston Properties, Inc. related to Common Stock issued under the Stock Option and Incentive Plan, net	172	340	3,476
Units issued to Boston Properties, Inc. related to Common Stock issued in exchange for OP Units	2,407	4,049	6,391
General Partners' Ending Balance	1,717,743	1,715,092	1,710,644
Boston Properties Limited Partnership | Limited Partner [Member]
Limited Partners' Capital Account [Line Items]
Limited Partners Beginning Balance	151,864,874	151,403,301	151,282,879
Units issued to Boston Properties, Inc. related to Common Stock issued under the Employee Stock Purchase Plan	5,623	6,140	6,409
Units issued to Boston Properties, Inc. related to Common Stock issued under the Stock Option and Incentive Plan, net	13,485	35,246	40,158
Units issued to Boston Properties, Inc. related to Common Stock issued in exchange for OP Units	188,450	420,187	73,855
Limited Partners' Ending Balance	152,072,432	151,864,874	151,403,301

Stockholders' Equity _ Partne89

Stockholders' Equity / Partners' Capital Partners' Capital Change in Series B Preferred Units (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Entity Information [Line Items]
Beginning Balance	$ 200,000
Ending Balance	200,000	$ 200,000
Boston Properties Limited Partnership
Entity Information [Line Items]
Beginning Balance	193,623	193,623	$ 193,623
Net Income	10,500	10,500	10,500
Distributions	(10,500)	(10,500)	(10,500)
Ending Balance	$ 193,623	$ 193,623	$ 193,623

Future Minimum Rents Narrative

Future Minimum Rents Narrative (Details) - tenants	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Future Minimum Rent [Line Items]
Number Of Tenants Above Concentration Amount.	0	0	0
Concentration Risk, Percentage	10.00%	10.00%	10.00%
Minimum [Member]
Future Minimum Rent [Line Items]
Initial Term Lease Expiration Date	2,017
Maximum [Member]
Future Minimum Rent [Line Items]
Initial Term Lease Expiration Date	2,046

Future Minimum Rents Future min

Future Minimum Rents Future minimum rent under non-cancelable operating leases (Details) $ in Thousands	Dec. 31, 2016USD ($)
Future minimum rent [Abstract]
2,017	$ 1,906,847
2,018	1,903,887
2,019	1,887,137
2,020	1,741,024
2,021	1,553,526
Thereafter	$ 9,367,433

Segment Information (Schedule O

Segment Information (Schedule Of Reconciliation Of Net Operating Income To Net Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Net income attributable to the Company's common shareholders / unitholders	$ 502,285	$ 572,606	$ 433,111
Preferred dividends / distributions	(10,500)	(10,500)	(10,500)
Noncontrolling interest-common units of the Operating Partnership	(59,260)	(66,951)	(50,862)
Noncontrolling interest - redeemable preferred units	0	(6)	(1,023)
Noncontrolling interest in property partnerships	2,068	(149,855)	(30,561)
Losses from interest rate contracts	(140)	0	0
Losses from early extinguishments of debt	(371)	(22,040)	(10,633)
Interest expense	(412,849)	(432,196)	(455,743)
Depreciation and amortization expense	(694,403)	(639,542)	(628,573)
Impairment loss	(1,783)	0	0
Transaction costs	(2,387)	(1,259)	(3,140)
General and administrative expense	(105,229)	(96,319)	(98,937)
Gains (losses) from investments in securities	(2,273)	653	(1,038)
Interest and other income	(7,230)	(6,777)	(8,765)
Gain on sale of investment in unconsolidated joint venture	(59,370)	0	0
Income from unconsolidated joint ventures	(8,074)	(22,770)	(12,769)
Development and management services income	(28,284)	(22,554)	(25,316)
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	502,285	572,606	433,111
Preferred dividends / distributions	10,500	10,500	10,500
Noncontrolling interest-common units of the Operating Partnership	59,260	66,951	50,862
Noncontrolling interest - redeemable preferred units	0	6	1,023
Noncontrolling interest in property partnerships	(2,068)	149,855	30,561
Losses from interest rate contracts	140	0	0
Losses from early extinguishments of debt	371	22,040	10,633
Interest expense	412,849	432,196	455,743
Depreciation and amortization expense	694,403	639,542	628,573
Impairment loss	1,783	0	0
Transaction costs	2,387	1,259	3,140
General and administrative expense	105,229	96,319	98,937
Gains on sales of real estate	80,606	375,895	168,039
Gains (losses) from investments in securities	2,273	(653)	1,038
Interest and other income	7,230	6,777	8,765
Gain on sale of investment in unconsolidated joint venture	59,370	0	0
Income from unconsolidated joint ventures	8,074	22,770	12,769
Development and management services income	28,284	22,554	25,316
Net Operating Income	1,601,302	1,563,931	1,507,156
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	575,341	648,748	499,129
Preferred dividends / distributions	(10,500)	(10,500)	(10,500)
Noncontrolling interest - redeemable preferred units	0	(6)	(1,023)
Noncontrolling interest in property partnerships	2,068	(149,855)	(30,561)
Losses from interest rate contracts	(140)	0	0
Losses from early extinguishments of debt	(371)	(22,040)	(10,633)
Interest expense	(412,849)	(432,196)	(455,743)
Depreciation and amortization expense	(682,776)	(631,549)	(620,064)
Impairment loss	(1,783)	0	0
Transaction costs	(2,387)	(1,259)	(3,140)
General and administrative expense	(105,229)	(96,319)	(98,937)
Gains (losses) from investments in securities	(2,273)	653	(1,038)
Interest and other income	(7,230)	(6,777)	(8,765)
Gain on sale of investment in unconsolidated joint venture	(59,370)	0	0
Income from unconsolidated joint ventures	(8,074)	(22,770)	(12,769)
Development and management services income	(28,284)	(22,554)	(25,316)
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	575,341	648,748	499,129
Preferred dividends / distributions	10,500	10,500	10,500
Noncontrolling interest - redeemable preferred units	0	6	1,023
Noncontrolling interest in property partnerships	(2,068)	149,855	30,561
Losses from interest rate contracts	140	0	0
Losses from early extinguishments of debt	371	22,040	10,633
Interest expense	412,849	432,196	455,743
Depreciation and amortization expense	682,776	631,549	620,064
Impairment loss	1,783	0	0
Transaction costs	2,387	1,259	3,140
General and administrative expense	105,229	96,319	98,937
Gains on sales of real estate	82,775	377,093	174,686
Gains (losses) from investments in securities	2,273	(653)	1,038
Interest and other income	7,230	6,777	8,765
Gain on sale of investment in unconsolidated joint venture	59,370	0	0
Income from unconsolidated joint ventures	8,074	22,770	12,769
Development and management services income	28,284	22,554	25,316
Net Operating Income	$ 1,601,302	$ 1,563,931	$ 1,507,156

Segment Information (Schedule93

Segment Information (Schedule Of Segment Reporting By Geographic Area And Property Type) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Rental Revenue: Class A Office	$ 2,460,953	$ 2,403,338	$ 2,302,104
Rental Revenue: Residential	16,699	18,883	26,193
Rental Revenue: Hotel	44,884	46,046	43,385
Rental Revenue Total	$ 2,522,536	$ 2,468,267	$ 2,371,682
Rental Revenue: % of Grand Totals	100.00%	100.00%	100.00%
Rental Expenses: Class A Office	$ 882,692	$ 864,025	$ 819,368
Rental Expenses: Residential	7,076	8,227	15,922
Rental Expenses: Hotel	31,466	32,084	29,236
Rental Expenses: Total	$ 921,234	$ 904,336	$ 864,526
Rental Expenses: % Of Grand Totals	100.00%	100.00%	100.00%
Net operating Income	$ 1,601,302	$ 1,563,931	$ 1,507,156
Net operating Income: % of Grand Totals	100.00%	100.00%	100.00%
Boston [Member]
Segment Reporting Information [Line Items]
Rental Revenue: Class A Office	$ 727,265	$ 716,246	$ 715,917
Rental Revenue: Residential	4,812	4,801	4,528
Rental Revenue: Hotel	44,884	46,046	43,385
Rental Revenue Total	$ 776,961	$ 767,093	$ 763,830
Rental Revenue: % of Grand Totals	30.80%	31.08%	32.21%
Rental Expenses: Class A Office	$ 282,827	$ 287,341	$ 278,120
Rental Expenses: Residential	2,708	2,006	1,957
Rental Expenses: Hotel	31,466	32,084	29,236
Rental Expenses: Total	$ 317,001	$ 321,431	$ 309,313
Rental Expenses: % Of Grand Totals	34.41%	35.54%	35.78%
Net operating Income	$ 459,960	$ 445,662	$ 454,517
Net operating Income: % of Grand Totals	28.73%	28.50%	30.16%
New York [Member]
Segment Reporting Information [Line Items]
Rental Revenue: Class A Office	$ 1,012,518	$ 1,000,030	$ 928,692
Rental Revenue: Residential	0	0	0
Rental Revenue: Hotel	0	0	0
Rental Revenue Total	$ 1,012,518	$ 1,000,030	$ 928,692
Rental Revenue: % of Grand Totals	40.14%	40.52%	39.16%
Rental Expenses: Class A Office	$ 363,188	$ 346,897	$ 315,330
Rental Expenses: Residential	0	0	0
Rental Expenses: Hotel	0	0	0
Rental Expenses: Total	$ 363,188	$ 346,897	$ 315,330
Rental Expenses: % Of Grand Totals	39.42%	38.36%	36.47%
Net operating Income	$ 649,330	$ 653,133	$ 613,362
Net operating Income: % of Grand Totals	40.55%	41.76%	40.70%
San Francisco [Member]
Segment Reporting Information [Line Items]
Rental Revenue: Class A Office	$ 318,609	$ 302,434	$ 261,221
Rental Revenue: Residential	0	0	0
Rental Revenue: Hotel	0	0	0
Rental Revenue Total	$ 318,609	$ 302,434	$ 261,221
Rental Revenue: % of Grand Totals	12.63%	12.25%	11.01%
Rental Expenses: Class A Office	$ 100,787	$ 98,206	$ 90,133
Rental Expenses: Residential	0	0	0
Rental Expenses: Hotel	0	0	0
Rental Expenses: Total	$ 100,787	$ 98,206	$ 90,133
Rental Expenses: % Of Grand Totals	10.94%	10.86%	10.43%
Net operating Income	$ 217,822	$ 204,228	$ 171,088
Net operating Income: % of Grand Totals	13.60%	13.06%	11.35%
Washington, DC [Member]
Segment Reporting Information [Line Items]
Rental Revenue: Class A Office	$ 402,561	$ 384,628	$ 396,274
Rental Revenue: Residential	11,887	14,082	21,665
Rental Revenue: Hotel	0	0	0
Rental Revenue Total	$ 414,448	$ 398,710	$ 417,939
Rental Revenue: % of Grand Totals	16.43%	16.15%	17.62%
Rental Expenses: Class A Office	$ 135,890	$ 131,581	$ 135,785
Rental Expenses: Residential	4,368	6,221	13,965
Rental Expenses: Hotel	0	0	0
Rental Expenses: Total	$ 140,258	$ 137,802	$ 149,750
Rental Expenses: % Of Grand Totals	15.23%	15.24%	17.32%
Net operating Income	$ 274,190	$ 260,908	$ 268,189
Net operating Income: % of Grand Totals	17.12%	16.68%	17.79%

Earnings Per Share _ Common U94

Earnings Per Share / Common Unit (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Basic Earnings:
Net income attributable to the Company's shareholders/unitholders (Numerator)									$ 502,285	$ 572,606	$ 433,111
Net income attributable to the Company in Shares / Units (Denominator)									153,715,000	153,471,000	153,089,000
Net income attributable to the Company's shareholders/unitholders (in dollars per share / unit)									$ 3.27	$ 3.73	$ 2.83
Allocation of undistributed earnings to participating securities (Numerator)									$ (283)
Allocation of undistributed earnings to participating securities (in shares) (Denominator)									0
Allocation of undistributed earnings to participating securities (in dollars per share / unit)									$ 0
Net income attributable to the Company Per Share / Unit Amount (in dollars per share / unit)	$ 0.96	$ 0.50	$ 0.63	$ 1.18	$ 0.90	$ 1.20	$ 0.52	$ 1.12	$ 3.27	$ 3.73	$ 2.83
Net Income Available To Common Stockholders After Allocation of Undistributed Earnings to Participating Securities Basic									$ 502,002
Weighted Average Number Of Shares Outstanding After Allocation of Undistributed Earnings to Participating Securities Basic (in shares)									153,715,000
Earnings Per Share After Allccation of Undistributed Earnings to Particiapting Securities Basic (dollars per share)									$ 3.27
Effect of Dilutive Securities:
Stock Based Compensation (Numerator)									$ 0	$ 0	$ 0
Stock Based Compensation, Shares / Units (Denominator)									262,000	373,000	219,000
Stock Based Compensation Per Share / Unit Amount									$ (0.01)	$ (0.01)	$ 0
Diluted Earnings:
Diluted Earnings: Net income attributable to the Company's shareholders/unitholdersIncome (Numerator)									$ 502,002	$ 572,606	$ 433,111
Diluted Earnings Net income attributable to the Company's shareholders/unitholders Shares / Units (Denominator)									153,977,000	153,844,000	153,308,000
Diluted Earnings: Net income, Per Share / Unit Amount (in dollars per share / unit)	0.96	0.50	0.63	1.18	0.90	1.20	0.52	1.11	$ 3.26	$ 3.72	$ 2.83
Boston Properties Limited Partnership
Redeemable Common Units									17,646,000	17,668,000	17,364,000
Basic Earnings:
Net income attributable to the Company's shareholders/unitholders (Numerator)									$ 575,341	$ 648,748	$ 499,129
Net income attributable to the Company in Shares / Units (Denominator)									171,361,000	171,139,000	170,453,000
Net income attributable to the Company's shareholders/unitholders (in dollars per share / unit)									$ 3.36	$ 3.79	$ 2.93
Allocation of undistributed earnings to participating securities (Numerator)									$ (316)
Allocation of undistributed earnings to participating securities (in shares) (Denominator)									0
Allocation of undistributed earnings to participating securities (in dollars per share / unit)									$ 0
Net income attributable to the Company Per Share / Unit Amount (in dollars per share / unit)	0.97	0.53	0.64	1.21	0.92	1.21	0.53	1.13	$ 3.36	$ 3.79	$ 2.93
Net Income Available To Common Stockholders After Allocation of Undistributed Earnings to Participating Securities Basic									$ 575,025
Weighted Average Number Of Shares Outstanding After Allocation of Undistributed Earnings to Participating Securities Basic (in shares)									171,361,000
Earnings Per Share After Allccation of Undistributed Earnings to Particiapting Securities Basic (dollars per share)									$ 3.36
Effect of Dilutive Securities:
Stock Based Compensation (Numerator)									$ 0	$ 0	$ 0
Stock Based Compensation, Shares / Units (Denominator)									262,000	373,000	219,000
Stock Based Compensation Per Share / Unit Amount									$ (0.01)	$ (0.01)	$ (0.01)
Diluted Earnings:
Diluted Earnings: Net income attributable to the Company's shareholders/unitholdersIncome (Numerator)									$ 575,025	$ 648,748	$ 499,129
Diluted Earnings Net income attributable to the Company's shareholders/unitholders Shares / Units (Denominator)									171,623,000	171,512,000	170,672,000
Diluted Earnings: Net income, Per Share / Unit Amount (in dollars per share / unit)	$ 0.97	$ 0.53	$ 0.64	$ 1.21	$ 0.92	$ 1.21	$ 0.53	$ 1.12	$ 3.35	$ 3.78	$ 2.92

Employee Benefit Plans (Details

Employee Benefit Plans (Details)	12 Months Ended			192 Months Ended	204 Months Ended
	Dec. 31, 2016USD ($)mo	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2016USD ($)yrage	Dec. 31, 2016USD ($)
Employee Benefit Plans [Abstract]
Eligibility Period For 401K Savings Plan In Months | mo	3
Employer Matching Contribution, Percent of Match					200.00%
Employer Matching Contribution, Percent of Employees' Gross Pay					3.00%
Maximum Eligible Earnings As Established By IRS For Matching Contributions	$ 265,000	$ 265,000	$ 260,000
Employer Contribution Amount	4,000,000	3,700,000	3,500,000
Years Of Service For Supplemental Retirement Contribution | yr				10
Age Of Employee For Supplemental Retirement Contribution | age				40
Annual Supplemental Retirement Contribution And Credit Total.	21,000	42,000	$ 52,000
Separate Unrestricted Cash For Deferred Compensation Plan.	23,800,000	20,400,000		$ 23,800,000	$ 23,800,000
Deferred Compensation Liability	$ 23,800,000	$ 20,400,000		$ 23,800,000	$ 23,800,000

Stock Option and Incentive Pl96

Stock Option and Incentive Plan (Narrative) (Details)	Feb. 04, 2016USD ($)shares	Jan. 25, 2016USD ($)yrindicestiers	Feb. 06, 2015USD ($)shares	May 15, 2012yrshares	Dec. 31, 2014USD ($)	Mar. 11, 2013USD ($)
MYLTIP 2,013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Value of MYLTIP Awards	$ 13,500,000
MYLTIP Units forfeited | shares	205,762
Final awards percentage of target	109.50%
OPP Units 2012 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential Awards Earned			$ 40,000,000
Outperformance awards earned			$ 32,100,000
Potential maximum amount of Outperformance Awards earned (percent)			80.00%
2012 OPP Units forfeited | shares			174,549
2012 Stock Option and Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Additional Shares Authorized | shares				13,000,000
Other Than Stock Options Awards Conversion Ratio				2.32
Stock Option Awards Conversion Ratio				1
Stock Option and Incentive Plan Term Period | yr				10
MYLTIP 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Tiers | tiers		3
TSR measurement (in years) | yr		3
Distributions percent before measurement date		10.00%
Indices Used to Compare TSR | indices		2
Threshold Tier		$ 9,900,000
Target Tier		19,700,000
High Tier		$ 49,300,000
Percentage of annualized TSR for Reduction of Earned Awards		0.00%
Percentage to Cause Some Awards to be Earned Even if on a Relative Basis it Would Not Result in any Earned Awards		12.00%
Value of MYLTIP Awards		$ 17,300,000
MYLTIP Value Amortized Into Earnings, Years | yr		4
Minimum [Member] | MYLTIP 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential Awards Earned		$ 0
Maximum [Member] | MYLTIP 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Potential Awards Earned		$ 49,300,000
Board of Directors Chairman [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash Payment Related to Transition Agreement						$ 6,700,000
Target Equity Award Compensation Associated with Transition Agreement						$ 11,100,000
Compensation Expense associated with Transition Agreement					$ 3,900,000
Cohen & Steers Realty Majors Portfolio Index [Member] | MYLTIP 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Percentage of Index Used to Compare to TSR		50.00%
NAREIT Office Index adjusted [Member] | MYLTIP 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted Percentage of Index Used to Compare to TSR		50.00%
MYLTIP vesting 2019 [Member] | MYLTIP 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Percentage		50.00%
MYLTIP vesting 2020 [Member] | MYLTIP 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Percentage		50.00%

Stock Option and Incentive Pl97

Stock Option and Incentive Plan (Restricted Stock) (Narrative) (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)VestingInstallmentsd$ / sharesshares	Dec. 31, 2015USD ($)$ / sharesshares	Dec. 31, 2014USD ($)$ / sharesshares	May 17, 2016shares	Jan. 01, 2015shares	May 20, 2014shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued	153,869,075	153,658,866		1,507		7,542
Stock-based compensation associated with restricted stock, non-qualified options, LTIP Units, 2012 OPP Units, and 2013-2016 MYLTIP Units | $	$ 30,600	$ 26,900	$ 26,000
Value of shares of common stock | $	1,538	$ 1,536
Exercisable, Weighted Average Exercise Price | $ / shares		$ 96.10	$ 96.91
Total intrinsic value of the outstanding and exercisable stock options | $	$ 15,200
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued	22,067	34,150	23,968
Employee and director payment per share (in dollars per share) | $ / shares	$ 0.01
Value of shares of common stock | $	$ 2,500	$ 4,800	$ 2,600
Employee's weighted average cost per share (in dollars per share) | $ / shares	$ 113.51	$ 140.88	$ 109.27
LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
LTIP units issued (in shares)			127,094
Value of LTIP units issued | $	$ 15,400	$ 13,500	$ 12,800
Per unit fair value weighted-average (in dollars per share) | $ / shares	$ 103.83	$ 128.94	$ 100.61
Expected life assumed to calculate per unit fair value per LTIP unit (years)	5 years 8 months 12 days	5 years 8 months 12 days	5 years 8 months 12 days
Risk-free rate	1.61%	1.47%	1.84%
Expected price volatility	33.00%	26.00%	27.00%
LTIPs And Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting annual installments | VestingInstallments	4
LTIPS snd Restricted Stock[Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expenses | $	$ 19,200
MYLTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation expenses | $	$ 19,600
Weighted-average period (years)	2 years 3 months 18 days
LTIPs, OPP and MYLTIP Awards [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
MYLTIP 2,014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
MYLTIP units issued			485,459
MYLTIP 2015 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
MYLTIP units issued		375,000
MYLTIP 2016 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
MYLTIP units issued	475,004
Non-Qualified Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum Common Stock available for issuance	250,000
Employee Common Stock options, percent of average closing price	85.00%
Number Of Days Used In Calculation, Average Closing Prices Of Common Stock | d	10
Shares issued	5,695	6,199	6,964
Shares issued, weighted-average purchase price per share | $ / shares	$ 109.27	$ 108.73	$ 93.37
Board of Directors Chairman [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation associated with restricted stock, non-qualified options, LTIP Units, 2012 OPP Units, and 2013-2016 MYLTIP Units | $			$ 2,500
Boston Properties Limited Partnership | LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
LTIP units issued (in shares)	147,872	190,563
Boston Properties Limited Partnership | Non-executive Chairman of the Board of Directors [Member] | LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
LTIP units issued (in shares)					85,962

Stock Option and Incentive Pl98

Stock Option and Incentive Plan Schedule of Stock Options Status (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning Outstanding, Shares	547,129	553,312	558,823
Beginning Oustanding, Weighted Average Exercise Price	$ 96.38	$ 97.21	$ 100.43
Exercised, Shares	0	(11,447)	21,459
Exercised, Weighted Averge Exercise Price	$ 0	$ 92.50	$ 97.04
Canceled, Shares			(2,444)
Canceled, Weighted Average Exercise Price			$ 103.57
Special dividend adjustment (shares)		5,264	18,392
Special dividend adjustment weighted average exercise price		$ 96.38	$ 97.22
Ending Outstanding, Shares	547,129	547,129	553,312
Ending Oustanding, Weighted Average Exercise Pric	$ 96.38	$ 96.38	$ 97.21

Stock Option and Incentive Pl99

Stock Option and Incentive Plan Schedule of Stock Options Outstanding (Details) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number Outstanding at period end	547,129	547,129	553,312	558,823
Outstanding, Weighted Average Exercise Price	$ 96.38	$ 96.38	$ 97.21	$ 100.43
Number Exercisable		465,371	411,143
Exercisable, Weighted Average Exercise Price		$ 96.10	$ 96.91
Exercise Price of $86.86 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Weighted Average Remaining Contractual Life (Years)	4 years 1 month 6 days
Number Outstanding at period end	118,502
Outstanding, Weighted Average Exercise Price	$ 86.86
Number Exercisable	118,502
Exercisable, Weighted Average Exercise Price	$ 86.86
Exercise Price of $95.69 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Weighted Average Remaining Contractual Life (Years)	6 years 3 months 18 days
Number Outstanding at period end	54,282
Outstanding, Weighted Average Exercise Price	$ 95.69
Number Exercisable	40,711
Exercisable, Weighted Average Exercise Price	$ 95.69
Exercise Price of $98.46 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Weighted Average Remaining Contractual Life (Years)	6 years 1 month 6 days
Number Outstanding at period end	206,728
Outstanding, Weighted Average Exercise Price	$ 98.46
Number Exercisable	187,530
Exercisable, Weighted Average Exercise Price	$ 98.46
Exercise Price of $100.77 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Weighted Average Remaining Contractual Life (Years)	5 years 1 month 6 days
Number Outstanding at period end	167,617
Outstanding, Weighted Average Exercise Price	$ 100.77
Number Exercisable	167,617
Exercisable, Weighted Average Exercise Price	$ 100.77

Related Party Transactions (Det

Related Party Transactions (Details)	12 Months Ended
	Dec. 31, 2016USD ($)nonemployeedirectorsshares	Dec. 31, 2015USD ($)shares	Dec. 31, 2014USD ($)	May 17, 2016shares	May 20, 2014shares
Related Party Transaction [Line Items]
Number Of Non Employee Directors Electing To Receive Deferred Stock Units | nonemployeedirectors	6
Shares issued | shares	153,869,075	153,658,866		1,507	7,542
Deferred Stock Units Outstanding	99,035	93,044
Executive Vice President and New York regional manager [Member]
Related Party Transaction [Line Items]
Aggregate leasing commissions paid to related parties	$ 315,000	$ 616,000	$ 1,214,000
Brother of Senior Executive Vice President [Member]
Related Party Transaction [Line Items]
Aggregate leasing commissions paid to related parties	$ 374,000	$ 384,000	$ 674,000

Selected Interim Financial I101

Selected Interim Financial Information (unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Total revenue	$ 636,061	$ 625,228	$ 623,546	$ 665,985	$ 624,240	$ 629,884	$ 618,221	$ 618,476	$ 2,550,820	$ 2,490,821	$ 2,396,998
Income before gains on sales of real estate	164,894	58,521	117,357	148,599	85,406	123,792	100,739	114,086	489,371	424,023	358,018
Net income attributable to the Company	$ 147,214	$ 76,753	$ 96,597	$ 181,747	$ 137,851	$ 184,082	$ 79,460	$ 171,182	$ 512,785	$ 583,106	$ 443,611
Income attributable to the Company (in dollars per share / unit) - Basic	$ 0.96	$ 0.50	$ 0.63	$ 1.18	$ 0.90	$ 1.20	$ 0.52	$ 1.12	$ 3.27	$ 3.73	$ 2.83
Income attributable to the Company (in dollars per share / unit) - Diluted	$ 0.96	$ 0.50	$ 0.63	$ 1.18	$ 0.90	$ 1.20	$ 0.52	$ 1.11	$ 3.26	$ 3.72	$ 2.83
Boston Properties Limited Partnership
Total revenue	$ 636,061	$ 625,228	$ 623,546	$ 665,985	$ 624,240	$ 629,884	$ 618,221	$ 618,476	$ 2,550,820	$ 2,490,821	$ 2,396,998
Income before gains on sales of real estate	167,384	63,687	119,341	150,586	87,404	125,790	102,737	116,085	500,998	432,016	366,527
Net income attributable to the Company	$ 166,801	$ 91,306	$ 109,938	$ 207,296	$ 156,901	$ 207,626	$ 90,852	$ 193,369	$ 585,841	$ 659,248	$ 509,629
Income attributable to the Company (in dollars per share / unit) - Basic	$ 0.97	$ 0.53	$ 0.64	$ 1.21	$ 0.92	$ 1.21	$ 0.53	$ 1.13	$ 3.36	$ 3.79	$ 2.93
Income attributable to the Company (in dollars per share / unit) - Diluted	$ 0.97	$ 0.53	$ 0.64	$ 1.21	$ 0.92	$ 1.21	$ 0.53	$ 1.12	$ 3.35	$ 3.78	$ 2.92

Subsequent Events subsequent Ev

Subsequent Events subsequent Events (Details)	Feb. 03, 2017USD ($)shares	Jan. 25, 2017USD ($)yrindicestiers	Dec. 31, 2016shares	May 17, 2016shares	Dec. 31, 2015shares	May 20, 2014shares
Subsequent Event [Line Items]
Common stock, shares issued | shares			153,869,075	1,507	153,658,866	7,542
MYLTIPS 2017 | NAREIT Office Index adjusted [Member]
Subsequent Event [Line Items]
Weighted Percentage of Index Used to Compare to TSR		50.00%
MYLTIP vesting 2021 | MYLTIPS 2017
Subsequent Event [Line Items]
Vesting Percentage		50.00%
Subsequent Event [Member]
Subsequent Event [Line Items]
LTIP units issued (in shares) | shares	100,639
Subsequent Event [Member] | MYLTIPS 2017
Subsequent Event [Line Items]
Threshold Tier		$ 10,700,000
Target Tier		21,300,000
High Tier		32,000,000
Exceptional Tier		$ 42,700,000
Indices Used to Compare TSR | indices		2
Number of Tiers | tiers		4
Percentage of annualized TSR for Reduction of Earned Awards		0.00%
Percentage to Cause Some Awards to be Earned Even if on a Relative Basis it Would Not Result in any Earned Awards		12.00%
Distributions percent before measurement date		10.00%
Value of MYLTIP Awards		$ 17,700,000
MYLTIP Value Amortized Into Earnings, Years | yr		4
TSR measurement (in years) | yr		3
Subsequent Event [Member] | MYLTIPS 2017 | Cohen & Steers Realty Majors Portfolio Index [Member]
Subsequent Event [Line Items]
Weighted Percentage of Index Used to Compare to TSR		50.00%
Subsequent Event [Member] | MYLTIP 2014
Subsequent Event [Line Items]
Final awards percentage of target	27.70%
Value of MYLTIP Awards	$ 3,500,000
MYLTIP Units forfeited | shares	447,386
Subsequent Event [Member] | Minimum [Member] | MYLTIPS 2017
Subsequent Event [Line Items]
Potential Awards Earned		$ 0
Subsequent Event [Member] | Maximum [Member] | MYLTIPS 2017
Subsequent Event [Line Items]
Potential Awards Earned		$ 42,700,000
Subsequent Event [Member] | MYLTIP vesting 2020 | MYLTIPS 2017
Subsequent Event [Line Items]
Vesting Percentage		50.00%
Subsequent Event [Member] | Restricted Stock [Member]
Subsequent Event [Line Items]
Common stock, shares issued | shares	35,839

Real Estate and Accumulated 103

Real Estate and Accumulated Depreciation Schedule of Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	[1]	$ 2,063,087
Original Land		4,759,821
Original Building		11,416,957
Costs Capitalized Subsequent to Acquisition		3,937,798
Land and improvements		4,879,020
Buildings and Improvements		13,950,941
Land Held for Development	[2]	246,656
Development and Construction in Progress		1,037,959
Total		20,114,576
Accumulated Depreciation		4,201,891
Furniture, fixtures and equipment		32,687	$ 29,852
Furniture, fixtures and equipment accumulated depreciation		20,344
Real Estate Aggregate Cost For Tax Purposes		15,800,000
Real Estate Aggregate Accumulated Depreciation For Tax Purposes		$ 3,200,000
Real Estate and Accumulated Depreciation, Life Used for Depreciation		40 years
Unamortized balance of historical fair value adjustments		$ 33,830
Unamortized deferred finance costs		$ (2,358)
767 Fifth Avenue (the General Motors Building)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		767 Fifth Avenue (the General Motors Building)
Type		Office
Location		New York, NY
Encumbrances		$ 1,333,625
Original Land		1,796,252
Original Building		1,532,654
Costs Capitalized Subsequent to Acquisition		75,211
Land and improvements		1,796,252
Buildings and Improvements		1,607,865
Land Held for Development		0
Development and Construction in Progress		0
Total		3,404,117
Accumulated Depreciation		$ 189,209
Year(s) built / renovated		1,968
Year(s) Acquired		2,013
Depreciable Lives (Years)	[3]	(1)
Prudential Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Prudential Center
Type		Office
Location		Boston, MA
Encumbrances		$ 0
Original Land		92,077
Original Building		734,594
Costs Capitalized Subsequent to Acquisition		656,606
Land and improvements		115,638
Buildings and Improvements		1,214,787
Land Held for Development		0
Development and Construction in Progress		152,852
Total		1,483,277
Accumulated Depreciation		$ 482,661
Year(s) built / renovated		1965/1993/2002/2016
Year(s) Acquired		1998/1999/2000
Depreciable Lives (Years)	[3]	(1)
Embarcadero Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Embarcadero Center
Type		Office
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		179,697
Original Building		847,410
Costs Capitalized Subsequent to Acquisition		343,726
Land and improvements		195,987
Buildings and Improvements		1,174,846
Land Held for Development		0
Development and Construction in Progress		0
Total		1,370,833
Accumulated Depreciation		$ 560,416
Year(s) built / renovated		1970/1989
Year(s) Acquired		1998-1999
Depreciable Lives (Years)	[3]	(1)
399 Park Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		399 Park Avenue
Type		Office
Location		New York, NY
Encumbrances		$ 0
Original Land		339,200
Original Building		700,358
Costs Capitalized Subsequent to Acquisition		132,062
Land and improvements		354,107
Buildings and Improvements		817,513
Land Held for Development		0
Development and Construction in Progress		0
Total		1,171,620
Accumulated Depreciation		$ 287,748
Year(s) built / renovated		1,961
Year(s) Acquired		2,002
Depreciable Lives (Years)	[3]	(1)
200 Clarendon Street and Garage
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		200 Clarendon Street and Garage
Type		Office
Location		Boston, MA
Encumbrances		$ 0
Original Land		219,543
Original Building		667,884
Costs Capitalized Subsequent to Acquisition		115,996
Land and improvements		219,616
Buildings and Improvements		777,557
Land Held for Development		6,250
Development and Construction in Progress		0
Total		1,003,423
Accumulated Depreciation		$ 140,629
Year(s) built / renovated		1,976
Year(s) Acquired		2,010
Depreciable Lives (Years)	[3]	(1)
601 Lexington Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		601 Lexington Avenue
Type		Office
Location		New York, NY
Encumbrances		$ 684,858
Original Land		241,600
Original Building		494,782
Costs Capitalized Subsequent to Acquisition		196,359
Land and improvements		289,639
Buildings and Improvements		620,487
Land Held for Development		0
Development and Construction in Progress		22,615
Total		932,741
Accumulated Depreciation		$ 239,984
Year(s) built / renovated		1977/1997
Year(s) Acquired		2,001
Depreciable Lives (Years)	[3]	(1)
250 West 55th Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		250 West 55th Street
Type		Office
Location		New York, NY
Encumbrances		$ 0
Original Land		285,263
Original Building		603,167
Costs Capitalized Subsequent to Acquisition		35,668
Land and improvements		285,263
Buildings and Improvements		638,835
Land Held for Development		0
Development and Construction in Progress		0
Total		924,098
Accumulated Depreciation		$ 49,852
Year(s) built / renovated		2,014
Year(s) Acquired		2,007
Depreciable Lives (Years)	[3]	(1)
Times Square Tower
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Times Square Tower
Type		Office
Location		New York, NY
Encumbrances		$ 0
Original Land		165,413
Original Building		380,438
Costs Capitalized Subsequent to Acquisition		87,583
Land and improvements		169,193
Buildings and Improvements		464,241
Land Held for Development		0
Development and Construction in Progress		0
Total		633,434
Accumulated Depreciation		$ 178,904
Year(s) built / renovated		2,004
Year(s) Acquired		2,000
Depreciable Lives (Years)	[3]	(1)
Carnegie Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Carnegie Center
Type		Office
Location		Princeton, NJ
Encumbrances		$ 0
Original Land		105,107
Original Building		377,259
Costs Capitalized Subsequent to Acquisition		149,576
Land and improvements		106,734
Buildings and Improvements		522,654
Land Held for Development		2,554
Development and Construction in Progress		0
Total		631,942
Accumulated Depreciation		$ 211,035
Year(s) built / renovated		1983-2016
Year(s) Acquired		1998/1999/2000/2007/2014
Depreciable Lives (Years)	[3]	(1)
100 Federal Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		100 Federal Street
Type		Office
Location		Boston, MA
Encumbrances		$ 0
Original Land		131,067
Original Building		435,954
Costs Capitalized Subsequent to Acquisition		38,611
Land and improvements		131,067
Buildings and Improvements		474,565
Land Held for Development		0
Development and Construction in Progress		0
Total		605,632
Accumulated Depreciation		$ 77,409
Year(s) built / renovated		1971-1975
Year(s) Acquired		2,012
Depreciable Lives (Years)	[3]	(1)
Atlantic Wharf
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Atlantic Wharf
Type		Office
Location		Boston, MA
Encumbrances		$ 0
Original Land		63,988
Original Building		454,537
Costs Capitalized Subsequent to Acquisition		17,442
Land and improvements		63,988
Buildings and Improvements		471,979
Land Held for Development		0
Development and Construction in Progress		0
Total		535,967
Accumulated Depreciation		$ 85,984
Year(s) built / renovated		2,011
Year(s) Acquired		2,007
Depreciable Lives (Years)	[3]	(1)
Fountain Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Fountain Square
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		56,853
Original Building		306,298
Costs Capitalized Subsequent to Acquisition		17,748
Land and improvements		56,853
Buildings and Improvements		320,759
Land Held for Development		3,287
Development and Construction in Progress		0
Total		380,899
Accumulated Depreciation		$ 50,106
Year(s) built / renovated		1986-1990
Year(s) Acquired		2,012
Depreciable Lives (Years)	[3]	(1)
510 Madison Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		510 Madison Avenue
Type		Office
Location		New York, NY
Encumbrances		$ 0
Original Land		103,000
Original Building		253,665
Costs Capitalized Subsequent to Acquisition		21,952
Land and improvements		103,000
Buildings and Improvements		275,617
Land Held for Development		0
Development and Construction in Progress		0
Total		378,617
Accumulated Depreciation		$ 44,515
Year(s) built / renovated		2,012
Year(s) Acquired		2,010
Depreciable Lives (Years)	[3]	(1)
599 Lexington Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		599 Lexington Avenue
Type		Office
Location		New York, NY
Encumbrances		$ 0
Original Land		81,040
Original Building		100,507
Costs Capitalized Subsequent to Acquisition		169,222
Land and improvements		87,852
Buildings and Improvements		262,917
Land Held for Development		0
Development and Construction in Progress		0
Total		350,769
Accumulated Depreciation		$ 168,776
Year(s) built / renovated		1,986
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
680 Folsom Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		680 Folsom Street
Type		Office
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		72,545
Original Building		219,766
Costs Capitalized Subsequent to Acquisition		7,352
Land and improvements		72,545
Buildings and Improvements		227,118
Land Held for Development		0
Development and Construction in Progress		0
Total		299,663
Accumulated Depreciation		$ 21,845
Year(s) built / renovated		2,014
Year(s) Acquired		2,012
Depreciable Lives (Years)	[3]	(1)
South of Market and Democracy Tower
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		South of Market and Democracy Tower
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		13,603
Original Building		237,479
Costs Capitalized Subsequent to Acquisition		15,455
Land and improvements		13,687
Buildings and Improvements		252,850
Land Held for Development		0
Development and Construction in Progress		0
Total		266,537
Accumulated Depreciation		$ 79,868
Year(s) built / renovated		2008-2009
Year(s) Acquired		2,003
Depreciable Lives (Years)	[3]	(1)
601 Massachusetts Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		601 Massachusetts Avenue
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		95,310
Original Building		165,173
Costs Capitalized Subsequent to Acquisition		12
Land and improvements		95,322
Buildings and Improvements		165,173
Land Held for Development		0
Development and Construction in Progress		0
Total		260,495
Accumulated Depreciation		$ 6,534
Year(s) built / renovated		2,016
Year(s) Acquired		2,008
Depreciable Lives (Years)	[3]	(1)
Bay Colony Corporate Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Bay Colony Corporate Center
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		18,789
Original Building		148,451
Costs Capitalized Subsequent to Acquisition		68,371
Land and improvements		18,789
Buildings and Improvements		216,822
Land Held for Development		0
Development and Construction in Progress		0
Total		235,611
Accumulated Depreciation		$ 46,015
Year(s) built / renovated		1985-1989
Year(s) Acquired		2,011
Depreciable Lives (Years)	[3]	(1)
Gateway Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Gateway Center
Type		Office
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		28,255
Original Building		139,245
Costs Capitalized Subsequent to Acquisition		55,680
Land and improvements		30,627
Buildings and Improvements		192,553
Land Held for Development		0
Development and Construction in Progress		0
Total		223,180
Accumulated Depreciation		$ 98,003
Year(s) built / renovated		1984/1986/2002
Year(s) Acquired		1,999
Depreciable Lives (Years)	[3]	(1)
535 Mission Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		535 Mission Street
Type		Office
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		40,933
Original Building		148,378
Costs Capitalized Subsequent to Acquisition		2,015
Land and improvements		40,933
Buildings and Improvements		150,393
Land Held for Development		0
Development and Construction in Progress		0
Total		191,326
Accumulated Depreciation		$ 8,844
Year(s) built / renovated		2,015
Year(s) Acquired		2,013
Depreciable Lives (Years)	[3]	(1)
2200 Pennsylvania Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		2200 Pennsylvania Avenue
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		0
Original Building		183,541
Costs Capitalized Subsequent to Acquisition		5,047
Land and improvements		0
Buildings and Improvements		188,588
Land Held for Development		0
Development and Construction in Progress		0
Total		188,588
Accumulated Depreciation		$ 39,956
Year(s) built / renovated		2,011
Year(s) Acquired		2,008
Depreciable Lives (Years)	[3]	(1)
Mountain View Research Park
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Mountain View Research Park
Type		Office
Location		Mountain View, CA
Encumbrances		$ 0
Original Land		95,066
Original Building		68,373
Costs Capitalized Subsequent to Acquisition		6,491
Land and improvements		95,066
Buildings and Improvements		74,864
Land Held for Development		0
Development and Construction in Progress		0
Total		169,930
Accumulated Depreciation		$ 12,849
Year(s) built / renovated		1977-1981/2007-2013
Year(s) Acquired		2,013
Depreciable Lives (Years)	[3]	(1)
Reservoir Place
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Reservoir Place
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		18,605
Original Building		92,619
Costs Capitalized Subsequent to Acquisition		53,163
Land and improvements		20,118
Buildings and Improvements		129,712
Land Held for Development		0
Development and Construction in Progress		14,557
Total		164,387
Accumulated Depreciation		$ 61,362
Year(s) built / renovated		1955/1987
Year(s) Acquired		1997/1998
Depreciable Lives (Years)	[3]	(1)
1330 Connecticut Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		1330 Connecticut Avenue
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		25,982
Original Building		82,311
Costs Capitalized Subsequent to Acquisition		32,276
Land and improvements		27,135
Buildings and Improvements		113,434
Land Held for Development		0
Development and Construction in Progress		0
Total		140,569
Accumulated Depreciation		$ 34,137
Year(s) built / renovated		1,984
Year(s) Acquired		2,004
Depreciable Lives (Years)	[3]	(1)
1333 New Hampshire Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		1333 New Hampshire Avenue
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		34,032
Original Building		85,660
Costs Capitalized Subsequent to Acquisition		11,147
Land and improvements		35,382
Buildings and Improvements		95,457
Land Held for Development		0
Development and Construction in Progress		0
Total		130,839
Accumulated Depreciation		$ 37,996
Year(s) built / renovated		1,996
Year(s) Acquired		2,003
Depreciable Lives (Years)	[3]	(1)
Kingstowne Towne Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kingstowne Towne Center
Type		Office
Location		Alexandria, VA
Encumbrances		$ 0
Original Land		18,021
Original Building		109,038
Costs Capitalized Subsequent to Acquisition		1,083
Land and improvements		18,062
Buildings and Improvements		110,080
Land Held for Development		0
Development and Construction in Progress		0
Total		128,142
Accumulated Depreciation		$ 36,551
Year(s) built / renovated		2003-2006
Year(s) Acquired		2,007
Depreciable Lives (Years)	[3]	(1)
Capital Gallery
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Capital Gallery
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		4,725
Original Building		29,565
Costs Capitalized Subsequent to Acquisition		89,028
Land and improvements		8,662
Buildings and Improvements		114,656
Land Held for Development		0
Development and Construction in Progress		0
Total		123,318
Accumulated Depreciation		$ 61,569
Year(s) built / renovated		1981/2006
Year(s) Acquired		2,007
Depreciable Lives (Years)	[3]	(1)
One Freedom Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		One Freedom Square
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		9,929
Original Building		84,504
Costs Capitalized Subsequent to Acquisition		28,646
Land and improvements		11,293
Buildings and Improvements		111,786
Land Held for Development		0
Development and Construction in Progress		0
Total		123,079
Accumulated Depreciation		$ 45,550
Year(s) built / renovated		2,000
Year(s) Acquired		2,003
Depreciable Lives (Years)	[3]	(1)
Weston Corporate Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Weston Corporate Center
Type		Office
Location		Weston, MA
Encumbrances		$ 0
Original Land		25,753
Original Building		92,312
Costs Capitalized Subsequent to Acquisition		(123)
Land and improvements		25,854
Buildings and Improvements		92,088
Land Held for Development		0
Development and Construction in Progress		0
Total		117,942
Accumulated Depreciation		$ 20,074
Year(s) built / renovated		2,010
Year(s) Acquired		2,001
Depreciable Lives (Years)	[3]	(1)
Two Freedom Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Two Freedom Square
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		13,930
Original Building		77,739
Costs Capitalized Subsequent to Acquisition		22,756
Land and improvements		15,420
Buildings and Improvements		99,005
Land Held for Development		0
Development and Construction in Progress		0
Total		114,425
Accumulated Depreciation		$ 44,569
Year(s) built / renovated		2,001
Year(s) Acquired		2,003
Depreciable Lives (Years)	[3]	(1)
One and Two Reston Overlook
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		One and Two Reston Overlook
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		16,456
Original Building		66,192
Costs Capitalized Subsequent to Acquisition		24,634
Land and improvements		16,179
Buildings and Improvements		91,103
Land Held for Development		0
Development and Construction in Progress		0
Total		107,282
Accumulated Depreciation		$ 40,513
Year(s) built / renovated		1,999
Year(s) Acquired		2,000
Depreciable Lives (Years)	[3]	(1)
Discovery Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Discovery Square
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		11,198
Original Building		71,782
Costs Capitalized Subsequent to Acquisition		22,642
Land and improvements		12,533
Buildings and Improvements		93,089
Land Held for Development		0
Development and Construction in Progress		0
Total		105,622
Accumulated Depreciation		$ 39,605
Year(s) built / renovated		2,001
Year(s) Acquired		2,003
Depreciable Lives (Years)	[3]	(1)
140 Kendrick Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		140 Kendrick Street
Type		Office
Location		Needham, MA
Encumbrances		$ 0
Original Land		18,095
Original Building		66,905
Costs Capitalized Subsequent to Acquisition		15,466
Land and improvements		19,092
Buildings and Improvements		81,374
Land Held for Development		0
Development and Construction in Progress		0
Total		100,466
Accumulated Depreciation		$ 26,141
Year(s) built / renovated		2,000
Year(s) Acquired		2,004
Depreciable Lives (Years)	[3]	(1)
355 Main Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		355 Main Street
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		18,863
Original Building		53,346
Costs Capitalized Subsequent to Acquisition		27,658
Land and improvements		21,173
Buildings and Improvements		78,694
Land Held for Development		0
Development and Construction in Progress		0
Total		99,867
Accumulated Depreciation		$ 25,345
Year(s) built / renovated		1981/1996/2013
Year(s) Acquired		2,006
Depreciable Lives (Years)	[3]	(1)
90 Broadway
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		90 Broadway
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		19,104
Original Building		52,078
Costs Capitalized Subsequent to Acquisition		17,048
Land and improvements		20,785
Buildings and Improvements		67,445
Land Held for Development		0
Development and Construction in Progress		0
Total		88,230
Accumulated Depreciation		$ 17,087
Year(s) built / renovated		1983/1998/2013
Year(s) Acquired		2,006
Depreciable Lives (Years)	[3]	(1)
10 CityPoint
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		10 CityPoint
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		1,953
Original Building		85,752
Costs Capitalized Subsequent to Acquisition		163
Land and improvements		2,116
Buildings and Improvements		85,752
Land Held for Development		0
Development and Construction in Progress		0
Total		87,868
Accumulated Depreciation		$ 1,601
Year(s) built / renovated		2,016
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
230 CityPoint
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		230 CityPoint
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		13,189
Original Building		49,823
Costs Capitalized Subsequent to Acquisition		20,187
Land and improvements		13,593
Buildings and Improvements		69,606
Land Held for Development		0
Development and Construction in Progress		0
Total		83,199
Accumulated Depreciation		$ 23,437
Year(s) built / renovated		1,992
Year(s) Acquired		2,005
Depreciable Lives (Years)	[3]	(1)
Waltham Weston Corporate Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Waltham Weston Corporate Center
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		10,385
Original Building		60,694
Costs Capitalized Subsequent to Acquisition		10,889
Land and improvements		11,097
Buildings and Improvements		70,871
Land Held for Development		0
Development and Construction in Progress		0
Total		81,968
Accumulated Depreciation		$ 27,310
Year(s) built / renovated		2,003
Year(s) Acquired		1,999
Depreciable Lives (Years)	[3]	(1)
77 CityPoint
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		77 CityPoint
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		13,847
Original Building		60,383
Costs Capitalized Subsequent to Acquisition		5,703
Land and improvements		13,873
Buildings and Improvements		66,060
Land Held for Development		0
Development and Construction in Progress		0
Total		79,933
Accumulated Depreciation		$ 20,981
Year(s) built / renovated		2,008
Year(s) Acquired		2,001
Depreciable Lives (Years)	[3]	(1)
3625-3635 Peterson Way
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		3625-3635 Peterson Way
Type		Office
Location		Santa Clara, CA
Encumbrances		$ 0
Original Land		63,206
Original Building		14,879
Costs Capitalized Subsequent to Acquisition		31
Land and improvements		63,206
Buildings and Improvements		14,879
Land Held for Development		31
Development and Construction in Progress		0
Total		78,116
Accumulated Depreciation		$ 2,093
Year(s) built / renovated		1,979
Year(s) Acquired		2,016
Depreciable Lives (Years)	[3]	(1)
North First Business Park
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		North First Business Park
Type		Office
Location		San Jose, CA
Encumbrances		$ 0
Original Land		58,402
Original Building		13,069
Costs Capitalized Subsequent to Acquisition		3,932
Land and improvements		23,377
Buildings and Improvements		16,116
Land Held for Development		35,910
Development and Construction in Progress		0
Total		75,403
Accumulated Depreciation		$ 15,811
Year(s) built / renovated		1,981
Year(s) Acquired		2,007
Depreciable Lives (Years)	[3]	(1)
2440 West El Camino Real
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		2440 West El Camino Real
Type		Office
Location		Mountain View, CA
Encumbrances		$ 0
Original Land		16,741
Original Building		51,285
Costs Capitalized Subsequent to Acquisition		1,814
Land and improvements		16,741
Buildings and Improvements		53,099
Land Held for Development		0
Development and Construction in Progress		0
Total		69,840
Accumulated Depreciation		$ 9,817
Year(s) built / renovated		1987/2003
Year(s) Acquired		2,011
Depreciable Lives (Years)	[3]	(1)
300 Binney Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		300 Binney Street
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		18,080
Original Building		51,262
Costs Capitalized Subsequent to Acquisition		140
Land and improvements		18,080
Buildings and Improvements		51,402
Land Held for Development		0
Development and Construction in Progress		0
Total		69,482
Accumulated Depreciation		$ 6,059
Year(s) built / renovated		2,013
Year(s) Acquired		2,009
Depreciable Lives (Years)	[3]	(1)
Reston Corporate Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Reston Corporate Center
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		9,135
Original Building		50,857
Costs Capitalized Subsequent to Acquisition		6,256
Land and improvements		10,148
Buildings and Improvements		56,100
Land Held for Development		0
Development and Construction in Progress		0
Total		66,248
Accumulated Depreciation		$ 25,244
Year(s) built / renovated		1,984
Year(s) Acquired		1,998
Depreciable Lives (Years)	[3]	(1)
Wisconsin Place
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Wisconsin Place
Type		Office
Location		Chevy Chase, MD
Encumbrances		$ 0
Original Land		0
Original Building		53,349
Costs Capitalized Subsequent to Acquisition		9,884
Land and improvements		0
Buildings and Improvements		63,233
Land Held for Development		0
Development and Construction in Progress		0
Total		63,233
Accumulated Depreciation		$ 16,406
Year(s) built / renovated		2,009
Year(s) Acquired		2,004
Depreciable Lives (Years)	[3]	(1)
New Dominion Technology Park, Bldg. Two
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		New Dominion Technology Park, Bldg. Two
Type		Office
Location		Herndon, VA
Encumbrances		$ 0
Original Land		5,584
Original Building		51,868
Costs Capitalized Subsequent to Acquisition		4,094
Land and improvements		6,510
Buildings and Improvements		55,036
Land Held for Development		0
Development and Construction in Progress		0
Total		61,546
Accumulated Depreciation		$ 21,908
Year(s) built / renovated		2,004
Year(s) Acquired		1,998
Depreciable Lives (Years)	[3]	(1)
200 West Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		200 West Street
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		16,148
Original Building		24,983
Costs Capitalized Subsequent to Acquisition		10,102
Land and improvements		16,813
Buildings and Improvements		34,420
Land Held for Development		0
Development and Construction in Progress		0
Total		51,233
Accumulated Depreciation		$ 19,535
Year(s) built / renovated		1,999
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
New Dominion Technology Park, Bldg. One
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		New Dominion Technology Park, Bldg. One
Type		Office
Location		Herndon, VA
Encumbrances		$ 35,485
Original Land		3,880
Original Building		43,227
Costs Capitalized Subsequent to Acquisition		3,883
Land and improvements		4,583
Buildings and Improvements		46,407
Land Held for Development		0
Development and Construction in Progress		0
Total		50,990
Accumulated Depreciation		$ 24,362
Year(s) built / renovated		2,001
Year(s) Acquired		1,998
Depreciable Lives (Years)	[3]	(1)
Sumner Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Sumner Square
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		624
Original Building		28,745
Costs Capitalized Subsequent to Acquisition		19,428
Land and improvements		1,478
Buildings and Improvements		47,319
Land Held for Development		0
Development and Construction in Progress		0
Total		48,797
Accumulated Depreciation		$ 22,237
Year(s) built / renovated		1,985
Year(s) Acquired		1,999
Depreciable Lives (Years)	[3]	(1)
University Place
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		University Place
Type		Office
Location		Cambridge, MA
Encumbrances		$ 9,119
Original Land		0
Original Building		37,091
Costs Capitalized Subsequent to Acquisition		9,501
Land and improvements		390
Buildings and Improvements		46,202
Land Held for Development		0
Development and Construction in Progress		0
Total		46,592
Accumulated Depreciation		$ 25,207
Year(s) built / renovated		1,985
Year(s) Acquired		1,998
Depreciable Lives (Years)	[3]	(1)
2600 Tower Oaks Boulevard
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		2600 Tower Oaks Boulevard
Type		Office
Location		Rockville, MD
Encumbrances		$ 0
Original Land		4,243
Original Building		31,125
Costs Capitalized Subsequent to Acquisition		9,081
Land and improvements		4,785
Buildings and Improvements		39,664
Land Held for Development		0
Development and Construction in Progress		0
Total		44,449
Accumulated Depreciation		$ 19,801
Year(s) built / renovated		2,001
Year(s) Acquired		1,998
Depreciable Lives (Years)	[3]	(1)
255 Main Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		255 Main Street
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		134
Original Building		25,110
Costs Capitalized Subsequent to Acquisition		17,087
Land and improvements		548
Buildings and Improvements		41,783
Land Held for Development		0
Development and Construction in Progress		0
Total		42,331
Accumulated Depreciation		$ 27,499
Year(s) built / renovated		1,987
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
Quorum Office Park
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Quorum Office Park
Type		Office
Location		Chelmsford, MA
Encumbrances		$ 0
Original Land		3,750
Original Building		32,454
Costs Capitalized Subsequent to Acquisition		5,813
Land and improvements		5,187
Buildings and Improvements		36,830
Land Held for Development		0
Development and Construction in Progress		0
Total		42,017
Accumulated Depreciation		$ 15,633
Year(s) built / renovated		2,001
Year(s) Acquired		2,000
Depreciable Lives (Years)	[3]	(1)
500 E Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		500 E Street
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		109
Original Building		22,420
Costs Capitalized Subsequent to Acquisition		13,219
Land and improvements		2,379
Buildings and Improvements		33,369
Land Held for Development		0
Development and Construction in Progress		0
Total		35,748
Accumulated Depreciation		$ 22,987
Year(s) built / renovated		1,987
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
150 Broadway
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		150 Broadway
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		850
Original Building		25,042
Costs Capitalized Subsequent to Acquisition		8,623
Land and improvements		1,323
Buildings and Improvements		33,192
Land Held for Development		0
Development and Construction in Progress		0
Total		34,515
Accumulated Depreciation		$ 15,545
Year(s) built / renovated		1,999
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
325 Main Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		325 Main Street
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		174
Original Building		12,200
Costs Capitalized Subsequent to Acquisition		12,256
Land and improvements		965
Buildings and Improvements		23,665
Land Held for Development		0
Development and Construction in Progress		0
Total		24,630
Accumulated Depreciation		$ 12,266
Year(s) built / renovated		1987/2013
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
105 Broadway
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		105 Broadway
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		1,299
Original Building		12,943
Costs Capitalized Subsequent to Acquisition		7,198
Land and improvements		2,395
Buildings and Improvements		19,045
Land Held for Development		0
Development and Construction in Progress		0
Total		21,440
Accumulated Depreciation		$ 13,018
Year(s) built / renovated		1,990
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
Lexington Office Park
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Lexington Office Park
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		998
Original Building		1,426
Costs Capitalized Subsequent to Acquisition		17,481
Land and improvements		1,264
Buildings and Improvements		18,641
Land Held for Development		0
Development and Construction in Progress		0
Total		19,905
Accumulated Depreciation		$ 12,490
Year(s) built / renovated		1,982
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
40 Shattuck Road
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		40 Shattuck Road
Type		Office
Location		Andover, MA
Encumbrances		$ 0
Original Land		709
Original Building		14,740
Costs Capitalized Subsequent to Acquisition		3,368
Land and improvements		893
Buildings and Improvements		17,924
Land Held for Development		0
Development and Construction in Progress		0
Total		18,817
Accumulated Depreciation		$ 7,505
Year(s) built / renovated		2,001
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
201 Spring Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		201 Spring Street
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		2,849
Original Building		15,303
Costs Capitalized Subsequent to Acquisition		14
Land and improvements		3,124
Buildings and Improvements		15,042
Land Held for Development		0
Development and Construction in Progress		0
Total		18,166
Accumulated Depreciation		$ 7,462
Year(s) built / renovated		1,997
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
The Point
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		The Point
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		6,395
Original Building		10,040
Costs Capitalized Subsequent to Acquisition		408
Land and improvements		6,480
Buildings and Improvements		10,363
Land Held for Development		0
Development and Construction in Progress		0
Total		16,843
Accumulated Depreciation		$ 397
Year(s) built / renovated		2,015
Year(s) Acquired		2,007
Depreciable Lives (Years)	[3]	(1)
92-100 Hayden Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		92-100 Hayden Avenue
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		594
Original Building		6,748
Costs Capitalized Subsequent to Acquisition		8,181
Land and improvements		802
Buildings and Improvements		14,721
Land Held for Development		0
Development and Construction in Progress		0
Total		15,523
Accumulated Depreciation		$ 12,062
Year(s) built / renovated		1,985
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
91 Hartwell Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		91 Hartwell Avenue
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		784
Original Building		6,464
Costs Capitalized Subsequent to Acquisition		8,254
Land and improvements		941
Buildings and Improvements		14,561
Land Held for Development		0
Development and Construction in Progress		0
Total		15,502
Accumulated Depreciation		$ 9,062
Year(s) built / renovated		1,985
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
690 Folsom Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		690 Folsom Street
Type		Office
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		3,219
Original Building		11,038
Costs Capitalized Subsequent to Acquisition		1,157
Land and improvements		3,219
Buildings and Improvements		12,195
Land Held for Development		0
Development and Construction in Progress		0
Total		15,414
Accumulated Depreciation		$ 801
Year(s) built / renovated		2,015
Year(s) Acquired		2,012
Depreciable Lives (Years)	[3]	(1)
145 Broadway
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		145 Broadway
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		121
Original Building		5,535
Costs Capitalized Subsequent to Acquisition		7,173
Land and improvements		324
Buildings and Improvements		10,637
Land Held for Development		0
Development and Construction in Progress		1,868
Total		12,829
Accumulated Depreciation		$ 8,676
Year(s) built / renovated		1,984
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
181 Spring Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		181 Spring Street
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		1,066
Original Building		9,520
Costs Capitalized Subsequent to Acquisition		2,195
Land and improvements		1,160
Buildings and Improvements		11,621
Land Held for Development		0
Development and Construction in Progress		0
Total		12,781
Accumulated Depreciation		$ 4,876
Year(s) built / renovated		1,999
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
195 West Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		195 West Street
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		1,611
Original Building		6,652
Costs Capitalized Subsequent to Acquisition		4,340
Land and improvements		1,858
Buildings and Improvements		10,745
Land Held for Development		0
Development and Construction in Progress		0
Total		12,603
Accumulated Depreciation		$ 7,517
Year(s) built / renovated		1,990
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
33 Hayden Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		33 Hayden Avenue
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		266
Original Building		3,234
Costs Capitalized Subsequent to Acquisition		8,787
Land and improvements		425
Buildings and Improvements		11,862
Land Held for Development		0
Development and Construction in Progress		0
Total		12,287
Accumulated Depreciation		$ 7,612
Year(s) built / renovated		1,979
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
7501 Boston Boulevard, Building Seven
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7501 Boston Boulevard, Building Seven
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		665
Original Building		9,273
Costs Capitalized Subsequent to Acquisition		535
Land and improvements		791
Buildings and Improvements		9,682
Land Held for Development		0
Development and Construction in Progress		0
Total		10,473
Accumulated Depreciation		$ 4,596
Year(s) built / renovated		1,997
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
7435 Boston Boulevard, Building One
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7435 Boston Boulevard, Building One
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		392
Original Building		3,822
Costs Capitalized Subsequent to Acquisition		5,116
Land and improvements		659
Buildings and Improvements		8,671
Land Held for Development		0
Development and Construction in Progress		0
Total		9,330
Accumulated Depreciation		$ 6,356
Year(s) built / renovated		1,982
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
250 Binney Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		250 Binney Street
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		110
Original Building		4,483
Costs Capitalized Subsequent to Acquisition		3,593
Land and improvements		273
Buildings and Improvements		7,913
Land Held for Development		0
Development and Construction in Progress		0
Total		8,186
Accumulated Depreciation		$ 4,684
Year(s) built / renovated		1,983
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
7450 Boston Boulevard, Building Three
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7450 Boston Boulevard, Building Three
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		1,165
Original Building		4,681
Costs Capitalized Subsequent to Acquisition		1,807
Land and improvements		1,430
Buildings and Improvements		6,223
Land Held for Development		0
Development and Construction in Progress		0
Total		7,653
Accumulated Depreciation		$ 3,321
Year(s) built / renovated		1,987
Year(s) Acquired		1,998
Depreciable Lives (Years)	[3]	(1)
8000 Grainger Court, Building Five
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		8000 Grainger Court, Building Five
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		366
Original Building		4,282
Costs Capitalized Subsequent to Acquisition		2,607
Land and improvements		601
Buildings and Improvements		6,654
Land Held for Development		0
Development and Construction in Progress		0
Total		7,255
Accumulated Depreciation		$ 5,416
Year(s) built / renovated		1,984
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
453 Ravendale Drive
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		453 Ravendale Drive
Type		Office
Location		Mountain View, CA
Encumbrances		$ 0
Original Land		5,477
Original Building		1,090
Costs Capitalized Subsequent to Acquisition		408
Land and improvements		5,477
Buildings and Improvements		1,498
Land Held for Development		0
Development and Construction in Progress		0
Total		6,975
Accumulated Depreciation		$ 338
Year(s) built / renovated		1,977
Year(s) Acquired		2,012
Depreciable Lives (Years)	[3]	(1)
7500 Boston Boulevard, Building Six
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7500 Boston Boulevard, Building Six
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		138
Original Building		3,749
Costs Capitalized Subsequent to Acquisition		2,487
Land and improvements		406
Buildings and Improvements		5,968
Land Held for Development		0
Development and Construction in Progress		0
Total		6,374
Accumulated Depreciation		$ 4,538
Year(s) built / renovated		1,985
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
17 Hartwell Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		17 Hartwell Avenue
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		26
Original Building		150
Costs Capitalized Subsequent to Acquisition		6,109
Land and improvements		65
Buildings and Improvements		6,220
Land Held for Development		0
Development and Construction in Progress		0
Total		6,285
Accumulated Depreciation		$ 552
Year(s) built / renovated		1,968
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
7601 Boston Boulevard, Building Eight
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7601 Boston Boulevard, Building Eight
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		200
Original Building		878
Costs Capitalized Subsequent to Acquisition		5,047
Land and improvements		551
Buildings and Improvements		5,574
Land Held for Development		0
Development and Construction in Progress		0
Total		6,125
Accumulated Depreciation		$ 4,043
Year(s) built / renovated		1,986
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
7300 Boston Boulevard, Building Thirteen
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7300 Boston Boulevard, Building Thirteen
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		608
Original Building		4,773
Costs Capitalized Subsequent to Acquisition		709
Land and improvements		661
Buildings and Improvements		5,429
Land Held for Development		0
Development and Construction in Progress		0
Total		6,090
Accumulated Depreciation		$ 5,012
Year(s) built / renovated		2,002
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
8000 Corporate Court, Building Eleven
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		8000 Corporate Court, Building Eleven
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		136
Original Building		3,071
Costs Capitalized Subsequent to Acquisition		1,615
Land and improvements		775
Buildings and Improvements		4,047
Land Held for Development		0
Development and Construction in Progress		0
Total		4,822
Accumulated Depreciation		$ 2,784
Year(s) built / renovated		1,989
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
7375 Boston Boulevard, Building Ten
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7375 Boston Boulevard, Building Ten
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		23
Original Building		2,685
Costs Capitalized Subsequent to Acquisition		912
Land and improvements		93
Buildings and Improvements		3,527
Land Held for Development		0
Development and Construction in Progress		0
Total		3,620
Accumulated Depreciation		$ 2,472
Year(s) built / renovated		1,988
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
7374 Boston Boulevard, Building Four
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7374 Boston Boulevard, Building Four
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		241
Original Building		1,605
Costs Capitalized Subsequent to Acquisition		1,738
Land and improvements		398
Buildings and Improvements		3,186
Land Held for Development		0
Development and Construction in Progress		0
Total		3,584
Accumulated Depreciation		$ 2,452
Year(s) built / renovated		1,984
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
7451 Boston Boulevard, Building Two
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7451 Boston Boulevard, Building Two
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		249
Original Building		1,542
Costs Capitalized Subsequent to Acquisition		1,659
Land and improvements		613
Buildings and Improvements		2,837
Land Held for Development		0
Development and Construction in Progress		0
Total		3,450
Accumulated Depreciation		$ 2,330
Year(s) built / renovated		1,982
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
32 Hartwell Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		32 Hartwell Avenue
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		168
Original Building		1,943
Costs Capitalized Subsequent to Acquisition		1,012
Land and improvements		314
Buildings and Improvements		2,809
Land Held for Development		0
Development and Construction in Progress		0
Total		3,123
Accumulated Depreciation		$ 1,905
Year(s) built / renovated		1968/1979/1987
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
164 Lexington Road
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		164 Lexington Road
Type		Office
Location		Billerica, MA
Encumbrances		$ 0
Original Land		592
Original Building		1,370
Costs Capitalized Subsequent to Acquisition		319
Land and improvements		643
Buildings and Improvements		1,638
Land Held for Development		0
Development and Construction in Progress		0
Total		2,281
Accumulated Depreciation		$ 827
Year(s) built / renovated		1,982
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
The Avant at Reston Town Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		The Avant at Reston Town Center
Type		Residential
Location		Reston, VA
Encumbrances		$ 0
Original Land		20,350
Original Building		91,995
Costs Capitalized Subsequent to Acquisition		815
Land and improvements		20,350
Buildings and Improvements		92,810
Land Held for Development		0
Development and Construction in Progress		0
Total		113,160
Accumulated Depreciation		$ 7,306
Year(s) built / renovated		2,014
Year(s) Acquired		2,010
Depreciable Lives (Years)	[3]	(1)
The Lofts at Atlantic Wharf
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		The Lofts at Atlantic Wharf
Type		Residential
Location		Boston, MA
Encumbrances		$ 0
Original Land		3,529
Original Building		54,891
Costs Capitalized Subsequent to Acquisition		1,663
Land and improvements		3,529
Buildings and Improvements		56,554
Land Held for Development		0
Development and Construction in Progress		0
Total		60,083
Accumulated Depreciation		$ 8,105
Year(s) built / renovated		2,011
Year(s) Acquired		2,007
Depreciable Lives (Years)	[3]	(1)
Boston Marriott Cambridge
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Boston Marriott Cambridge
Type		Hotel
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		478
Original Building		37,918
Costs Capitalized Subsequent to Acquisition		37,067
Land and improvements		1,201
Buildings and Improvements		74,262
Land Held for Development		0
Development and Construction in Progress		0
Total		75,463
Accumulated Depreciation		$ 50,954
Year(s) built / renovated		1,986
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
Kendall Center Green Garage
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Green Garage
Type		Garage
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		0
Original Building		35,035
Costs Capitalized Subsequent to Acquisition		7,391
Land and improvements		103
Buildings and Improvements		42,323
Land Held for Development		0
Development and Construction in Progress		0
Total		42,426
Accumulated Depreciation		$ 9,334
Year(s) built / renovated		1,984
Year(s) Acquired		2,006
Depreciable Lives (Years)	[3]	(1)
Kendall Center Yellow Garage
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Yellow Garage
Type		Garage
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		1,256
Original Building		15,697
Costs Capitalized Subsequent to Acquisition		1,571
Land and improvements		1,434
Buildings and Improvements		17,090
Land Held for Development		0
Development and Construction in Progress		0
Total		18,524
Accumulated Depreciation		$ 4,723
Year(s) built / renovated		2,006
Year(s) Acquired		2,004
Depreciable Lives (Years)	[3]	(1)
Kendall Center Blue Garage
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Blue Garage
Type		Garage
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		1,163
Original Building		11,633
Costs Capitalized Subsequent to Acquisition		2,770
Land and improvements		1,579
Buildings and Improvements		13,987
Land Held for Development		0
Development and Construction in Progress		0
Total		15,566
Accumulated Depreciation		$ 9,325
Year(s) built / renovated		1,990
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
Salesforce Tower
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Salesforce Tower
Type		Development
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		723,866
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		0
Development and Construction in Progress		723,866
Total		723,866
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,013
Depreciable Lives (Years)		N/A
Signature at Reston (formerly Reston Signature Site)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Signature at Reston (formerly Reston Signature Site)
Type		Development
Location		Reston, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		96,444
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		0
Development and Construction in Progress		96,444
Total		96,444
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,013
Depreciable Lives (Years)		N/A
191 Spring Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		191 Spring Street
Type		Development
Location		Lexington, MA
Encumbrances		$ 0
Original Land		2,850
Original Building		27,166
Costs Capitalized Subsequent to Acquisition		3,134
Land and improvements		3,151
Buildings and Improvements		28,576
Land Held for Development		0
Development and Construction in Progress		1,423
Total		33,150
Accumulated Depreciation		$ 21,660
Year(s) built / renovated		1971/1995
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
Proto at Cambridge (formerly Cambridge Residential / 88 Ames)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Proto at Cambridge (formerly Cambridge Residential / 88 Ames)
Type		Development
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		24,334
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		0
Development and Construction in Progress		24,334
Total		24,334
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,015
Depreciable Lives (Years)		N/A
Springfield Metro Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Springfield Metro Center
Type		Land
Location		Springfield, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		35,430
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		35,430
Development and Construction in Progress		0
Total		35,430
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,007
Depreciable Lives (Years)		N/A
Tower Oaks Master Plan
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Tower Oaks Master Plan
Type		Land
Location		Rockville, MD
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		29,209
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		29,209
Development and Construction in Progress		0
Total		29,209
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		1,998
Depreciable Lives (Years)		N/A
Plaza at Almaden
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Plaza at Almaden
Type		Land
Location		San Jose, CA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		29,081
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		29,081
Development and Construction in Progress		0
Total		29,081
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,006
Depreciable Lives (Years)		N/A
6601 & 6605 Springfield Center Drive
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		6601 & 6605 Springfield Center Drive
Type		Land
Location		Springfield, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		13,866
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		13,866
Development and Construction in Progress		0
Total		13,866
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,007
Depreciable Lives (Years)		N/A
214 Third Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		214 Third Avenue
Type		Land
Location		Waltham, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		13,795
Land and improvements		0
Buildings and Improvements		146
Land Held for Development		13,649
Development and Construction in Progress		0
Total		13,795
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,006
Depreciable Lives (Years)		N/A
103 Fourth Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		103 Fourth Avenue
Type		Land
Location		Waltham, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		12,052
Land and improvements		0
Buildings and Improvements		49
Land Held for Development		12,003
Development and Construction in Progress		0
Total		12,052
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,007
Depreciable Lives (Years)		N/A
20 CityPoint
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		20 CityPoint
Type		Land
Location		Waltham, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		11,666
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		11,666
Development and Construction in Progress		0
Total		11,666
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,007
Depreciable Lives (Years)		N/A
Reston Gateway
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Reston Gateway
Type		Land
Location		Reston, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		10,841
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		10,841
Development and Construction in Progress		0
Total		10,841
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		1,998
Depreciable Lives (Years)		N/A
Reston Eastgate
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Reston Eastgate
Type		Land
Location		Reston, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		9,906
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		9,906
Development and Construction in Progress		0
Total		9,906
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,001
Depreciable Lives (Years)		N/A
Crane Meadow
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Crane Meadow
Type		Land
Location		Marlborough, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		8,754
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		8,754
Development and Construction in Progress		0
Total		8,754
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,000
Depreciable Lives (Years)		N/A
Washingtonian North
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Washingtonian North
Type		Land
Location		Gaithersburg, MD
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		7,697
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		7,697
Development and Construction in Progress		0
Total		7,697
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		1,998
Depreciable Lives (Years)		N/A
Kendall Center Master Plan
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Master Plan
Type		Land
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		4,062
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		4,062
Development and Construction in Progress		0
Total		4,062
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		N/A
Depreciable Lives (Years)		N/A
Fourth and Harrison
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Fourth and Harrison
Type		Land
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		3,936
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		3,936
Development and Construction in Progress		0
Total		3,936
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		N/A
Depreciable Lives (Years)		N/A
North First Master Plan
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		North First Master Plan
Type		Land
Location		San Jose, CA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		3,014
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		3,014
Development and Construction in Progress		0
Total		3,014
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,007
Depreciable Lives (Years)		N/A
Broad Run Business Park
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Broad Run Business Park
Type		Land
Location		Loudoun County, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		2,694
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		2,694
Development and Construction in Progress		0
Total		2,694
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		1,998
Depreciable Lives (Years)		N/A
MacArthur Station
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		MacArthur Station
Type		Land
Location		Oakland, CA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		1,316
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		1,316
Development and Construction in Progress		0
Total		1,316
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		N/A
Depreciable Lives (Years)		N/A
30 Shattuck Road
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		30 Shattuck Road
Type		Land
Location		Andover, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		1,214
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		1,214
Development and Construction in Progress		0
Total		1,214
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		1,997
Depreciable Lives (Years)		N/A
2100 Pennsylvania Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		2100 Pennsylvania Avenue
Type		Land
Location		Washington, DC
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		286
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		286
Development and Construction in Progress		0
Total		286
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		N/A
Depreciable Lives (Years)		N/A
Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Life Used for Depreciation		life of the lease
[1]	Includes the unamortized balance of the historical fair value adjustment and unamortized deferred financing costs totaling approximately $33.8 million and $(2.4) million, respectively.
[2]	Includes pre-development costs.
[3]	Depreciation of the buildings and improvements are calculated over lives ranging from the life of the lease to 40 years.

Real Estate and Accumulated 104

Real Estate and Accumulated Depreciation Activity of Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Real Estate, Balance at the beginning of the year	$ 19,451,683	$ 19,208,417	$ 18,953,601
Real Estate, Additions to / improvements of real estate	977,287	700,792	594,296
Real Estate, Assets sold / written off	(314,394)	(457,526)	(339,480)
Real Estate, Balance at the end of the year	20,114,576	19,451,683	19,208,417
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Accumulated depreciation, Balance at beginning of the year	3,905,940	3,529,978	3,145,701
Accumulated depreciation, Depreciation expense	560,024	486,450	456,176
Accumulated depreciation, Assets sold / written off	(264,073)	(110,488)	(71,899)
Accumulated depreciation, Balance at end of the year	$ 4,201,891	$ 3,905,940	$ 3,529,978

Real Estate and Accumulated 105

Real Estate and Accumulated Depreciation Schedule of Real Estate and Accumulated Depreciation (BPLP) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	[1]	$ 2,063,087
Original Land		4,759,821
Original Building		11,416,957
Costs Capitalized Subsequent to Acquisition		3,937,798
Land and improvements		4,879,020
Buildings and Improvements		13,950,941
Land Held for Development	[2]	246,656
Development and Construction in Progress		1,037,959
Total		20,114,576
Accumulated Depreciation		4,201,891
Furniture, fixtures and equipment		32,687	$ 29,852
Furniture, fixtures and equipment accumulated depreciation		20,344
Real Estate Aggregate Cost For Tax Purposes		15,800,000
Real Estate Aggregate Accumulated Depreciation For Tax Purposes		$ 3,200,000
Real Estate and Accumulated Depreciation, Life Used for Depreciation		40 years
Unamortized balance of historical fair value adjustments		$ 33,830
Unamortized deferred finance costs		$ 2,358
767 Fifth Avenue (the General Motors Building)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		767 Fifth Avenue (the General Motors Building)
Type		Office
Location		New York, NY
Encumbrances		$ 1,333,625
Original Land		1,796,252
Original Building		1,532,654
Costs Capitalized Subsequent to Acquisition		75,211
Land and improvements		1,796,252
Buildings and Improvements		1,607,865
Land Held for Development		0
Development and Construction in Progress		0
Total		3,404,117
Accumulated Depreciation		$ 189,209
Year(s) built / renovated		1,968
Year(s) Acquired		2,013
Depreciable Lives (Years)	[3]	(1)
Prudential Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Prudential Center
Type		Office
Location		Boston, MA
Encumbrances		$ 0
Original Land		92,077
Original Building		734,594
Costs Capitalized Subsequent to Acquisition		656,606
Land and improvements		115,638
Buildings and Improvements		1,214,787
Land Held for Development		0
Development and Construction in Progress		152,852
Total		1,483,277
Accumulated Depreciation		$ 482,661
Year(s) built / renovated		1965/1993/2002/2016
Year(s) Acquired		1998/1999/2000
Depreciable Lives (Years)	[3]	(1)
Embarcadero Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Embarcadero Center
Type		Office
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		179,697
Original Building		847,410
Costs Capitalized Subsequent to Acquisition		343,726
Land and improvements		195,987
Buildings and Improvements		1,174,846
Land Held for Development		0
Development and Construction in Progress		0
Total		1,370,833
Accumulated Depreciation		$ 560,416
Year(s) built / renovated		1970/1989
Year(s) Acquired		1998-1999
Depreciable Lives (Years)	[3]	(1)
399 Park Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		399 Park Avenue
Type		Office
Location		New York, NY
Encumbrances		$ 0
Original Land		339,200
Original Building		700,358
Costs Capitalized Subsequent to Acquisition		132,062
Land and improvements		354,107
Buildings and Improvements		817,513
Land Held for Development		0
Development and Construction in Progress		0
Total		1,171,620
Accumulated Depreciation		$ 287,748
Year(s) built / renovated		1,961
Year(s) Acquired		2,002
Depreciable Lives (Years)	[3]	(1)
200 Clarendon Street and Garage
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		200 Clarendon Street and Garage
Type		Office
Location		Boston, MA
Encumbrances		$ 0
Original Land		219,543
Original Building		667,884
Costs Capitalized Subsequent to Acquisition		115,996
Land and improvements		219,616
Buildings and Improvements		777,557
Land Held for Development		6,250
Development and Construction in Progress		0
Total		1,003,423
Accumulated Depreciation		$ 140,629
Year(s) built / renovated		1,976
Year(s) Acquired		2,010
Depreciable Lives (Years)	[3]	(1)
250 West 55th Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		250 West 55th Street
Type		Office
Location		New York, NY
Encumbrances		$ 0
Original Land		285,263
Original Building		603,167
Costs Capitalized Subsequent to Acquisition		35,668
Land and improvements		285,263
Buildings and Improvements		638,835
Land Held for Development		0
Development and Construction in Progress		0
Total		924,098
Accumulated Depreciation		$ 49,852
Year(s) built / renovated		2,014
Year(s) Acquired		2,007
Depreciable Lives (Years)	[3]	(1)
601 Lexington Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		601 Lexington Avenue
Type		Office
Location		New York, NY
Encumbrances		$ 684,858
Original Land		241,600
Original Building		494,782
Costs Capitalized Subsequent to Acquisition		196,359
Land and improvements		289,639
Buildings and Improvements		620,487
Land Held for Development		0
Development and Construction in Progress		22,615
Total		932,741
Accumulated Depreciation		$ 239,984
Year(s) built / renovated		1977/1997
Year(s) Acquired		2,001
Depreciable Lives (Years)	[3]	(1)
Carnegie Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Carnegie Center
Type		Office
Location		Princeton, NJ
Encumbrances		$ 0
Original Land		105,107
Original Building		377,259
Costs Capitalized Subsequent to Acquisition		149,576
Land and improvements		106,734
Buildings and Improvements		522,654
Land Held for Development		2,554
Development and Construction in Progress		0
Total		631,942
Accumulated Depreciation		$ 211,035
Year(s) built / renovated		1983-2016
Year(s) Acquired		1998/1999/2000/2007/2014
Depreciable Lives (Years)	[3]	(1)
100 Federal Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		100 Federal Street
Type		Office
Location		Boston, MA
Encumbrances		$ 0
Original Land		131,067
Original Building		435,954
Costs Capitalized Subsequent to Acquisition		38,611
Land and improvements		131,067
Buildings and Improvements		474,565
Land Held for Development		0
Development and Construction in Progress		0
Total		605,632
Accumulated Depreciation		$ 77,409
Year(s) built / renovated		1971-1975
Year(s) Acquired		2,012
Depreciable Lives (Years)	[3]	(1)
Times Square Tower
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Times Square Tower
Type		Office
Location		New York, NY
Encumbrances		$ 0
Original Land		165,413
Original Building		380,438
Costs Capitalized Subsequent to Acquisition		87,583
Land and improvements		169,193
Buildings and Improvements		464,241
Land Held for Development		0
Development and Construction in Progress		0
Total		633,434
Accumulated Depreciation		$ 178,904
Year(s) built / renovated		2,004
Year(s) Acquired		2,000
Depreciable Lives (Years)	[3]	(1)
Atlantic Wharf
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Atlantic Wharf
Type		Office
Location		Boston, MA
Encumbrances		$ 0
Original Land		63,988
Original Building		454,537
Costs Capitalized Subsequent to Acquisition		17,442
Land and improvements		63,988
Buildings and Improvements		471,979
Land Held for Development		0
Development and Construction in Progress		0
Total		535,967
Accumulated Depreciation		$ 85,984
Year(s) built / renovated		2,011
Year(s) Acquired		2,007
Depreciable Lives (Years)	[3]	(1)
Fountain Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Fountain Square
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		56,853
Original Building		306,298
Costs Capitalized Subsequent to Acquisition		17,748
Land and improvements		56,853
Buildings and Improvements		320,759
Land Held for Development		3,287
Development and Construction in Progress		0
Total		380,899
Accumulated Depreciation		$ 50,106
Year(s) built / renovated		1986-1990
Year(s) Acquired		2,012
Depreciable Lives (Years)	[3]	(1)
510 Madison Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		510 Madison Avenue
Type		Office
Location		New York, NY
Encumbrances		$ 0
Original Land		103,000
Original Building		253,665
Costs Capitalized Subsequent to Acquisition		21,952
Land and improvements		103,000
Buildings and Improvements		275,617
Land Held for Development		0
Development and Construction in Progress		0
Total		378,617
Accumulated Depreciation		$ 44,515
Year(s) built / renovated		2,012
Year(s) Acquired		2,010
Depreciable Lives (Years)	[3]	(1)
599 Lexington Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		599 Lexington Avenue
Type		Office
Location		New York, NY
Encumbrances		$ 0
Original Land		81,040
Original Building		100,507
Costs Capitalized Subsequent to Acquisition		169,222
Land and improvements		87,852
Buildings and Improvements		262,917
Land Held for Development		0
Development and Construction in Progress		0
Total		350,769
Accumulated Depreciation		$ 168,776
Year(s) built / renovated		1,986
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
680 Folsom Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		680 Folsom Street
Type		Office
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		72,545
Original Building		219,766
Costs Capitalized Subsequent to Acquisition		7,352
Land and improvements		72,545
Buildings and Improvements		227,118
Land Held for Development		0
Development and Construction in Progress		0
Total		299,663
Accumulated Depreciation		$ 21,845
Year(s) built / renovated		2,014
Year(s) Acquired		2,012
Depreciable Lives (Years)	[3]	(1)
South of Market and Democracy Tower
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		South of Market and Democracy Tower
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		13,603
Original Building		237,479
Costs Capitalized Subsequent to Acquisition		15,455
Land and improvements		13,687
Buildings and Improvements		252,850
Land Held for Development		0
Development and Construction in Progress		0
Total		266,537
Accumulated Depreciation		$ 79,868
Year(s) built / renovated		2008-2009
Year(s) Acquired		2,003
Depreciable Lives (Years)	[3]	(1)
601 Massachusetts Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		601 Massachusetts Avenue
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		95,310
Original Building		165,173
Costs Capitalized Subsequent to Acquisition		12
Land and improvements		95,322
Buildings and Improvements		165,173
Land Held for Development		0
Development and Construction in Progress		0
Total		260,495
Accumulated Depreciation		$ 6,534
Year(s) built / renovated		2,016
Year(s) Acquired		2,008
Depreciable Lives (Years)	[3]	(1)
Bay Colony Corporate Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Bay Colony Corporate Center
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		18,789
Original Building		148,451
Costs Capitalized Subsequent to Acquisition		68,371
Land and improvements		18,789
Buildings and Improvements		216,822
Land Held for Development		0
Development and Construction in Progress		0
Total		235,611
Accumulated Depreciation		$ 46,015
Year(s) built / renovated		1985-1989
Year(s) Acquired		2,011
Depreciable Lives (Years)	[3]	(1)
Gateway Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Gateway Center
Type		Office
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		28,255
Original Building		139,245
Costs Capitalized Subsequent to Acquisition		55,680
Land and improvements		30,627
Buildings and Improvements		192,553
Land Held for Development		0
Development and Construction in Progress		0
Total		223,180
Accumulated Depreciation		$ 98,003
Year(s) built / renovated		1984/1986/2002
Year(s) Acquired		1,999
Depreciable Lives (Years)	[3]	(1)
535 Mission Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		535 Mission Street
Type		Office
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		40,933
Original Building		148,378
Costs Capitalized Subsequent to Acquisition		2,015
Land and improvements		40,933
Buildings and Improvements		150,393
Land Held for Development		0
Development and Construction in Progress		0
Total		191,326
Accumulated Depreciation		$ 8,844
Year(s) built / renovated		2,015
Year(s) Acquired		2,013
Depreciable Lives (Years)	[3]	(1)
2200 Pennsylvania Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		2200 Pennsylvania Avenue
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		0
Original Building		183,541
Costs Capitalized Subsequent to Acquisition		5,047
Land and improvements		0
Buildings and Improvements		188,588
Land Held for Development		0
Development and Construction in Progress		0
Total		188,588
Accumulated Depreciation		$ 39,956
Year(s) built / renovated		2,011
Year(s) Acquired		2,008
Depreciable Lives (Years)	[3]	(1)
Mountain View Research Park
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Mountain View Research Park
Type		Office
Location		Mountain View, CA
Encumbrances		$ 0
Original Land		95,066
Original Building		68,373
Costs Capitalized Subsequent to Acquisition		6,491
Land and improvements		95,066
Buildings and Improvements		74,864
Land Held for Development		0
Development and Construction in Progress		0
Total		169,930
Accumulated Depreciation		$ 12,849
Year(s) built / renovated		1977-1981/2007-2013
Year(s) Acquired		2,013
Depreciable Lives (Years)	[3]	(1)
Reservoir Place
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Reservoir Place
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		18,605
Original Building		92,619
Costs Capitalized Subsequent to Acquisition		53,163
Land and improvements		20,118
Buildings and Improvements		129,712
Land Held for Development		0
Development and Construction in Progress		14,557
Total		164,387
Accumulated Depreciation		$ 61,362
Year(s) built / renovated		1955/1987
Year(s) Acquired		1997/1998
Depreciable Lives (Years)	[3]	(1)
1330 Connecticut Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		1330 Connecticut Avenue
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		25,982
Original Building		82,311
Costs Capitalized Subsequent to Acquisition		32,276
Land and improvements		27,135
Buildings and Improvements		113,434
Land Held for Development		0
Development and Construction in Progress		0
Total		140,569
Accumulated Depreciation		$ 34,137
Year(s) built / renovated		1,984
Year(s) Acquired		2,004
Depreciable Lives (Years)	[3]	(1)
Kingstowne Towne Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kingstowne Towne Center
Type		Office
Location		Alexandria, VA
Encumbrances		$ 0
Original Land		18,021
Original Building		109,038
Costs Capitalized Subsequent to Acquisition		1,083
Land and improvements		18,062
Buildings and Improvements		110,080
Land Held for Development		0
Development and Construction in Progress		0
Total		128,142
Accumulated Depreciation		$ 36,551
Year(s) built / renovated		2003-2006
Year(s) Acquired		2,007
Depreciable Lives (Years)	[3]	(1)
1333 New Hampshire Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		1333 New Hampshire Avenue
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		34,032
Original Building		85,660
Costs Capitalized Subsequent to Acquisition		11,147
Land and improvements		35,382
Buildings and Improvements		95,457
Land Held for Development		0
Development and Construction in Progress		0
Total		130,839
Accumulated Depreciation		$ 37,996
Year(s) built / renovated		1,996
Year(s) Acquired		2,003
Depreciable Lives (Years)	[3]	(1)
Weston Corporate Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Weston Corporate Center
Type		Office
Location		Weston, MA
Encumbrances		$ 0
Original Land		25,753
Original Building		92,312
Costs Capitalized Subsequent to Acquisition		(123)
Land and improvements		25,854
Buildings and Improvements		92,088
Land Held for Development		0
Development and Construction in Progress		0
Total		117,942
Accumulated Depreciation		$ 20,074
Year(s) built / renovated		2,010
Year(s) Acquired		2,001
Depreciable Lives (Years)	[3]	(1)
One Freedom Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		One Freedom Square
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		9,929
Original Building		84,504
Costs Capitalized Subsequent to Acquisition		28,646
Land and improvements		11,293
Buildings and Improvements		111,786
Land Held for Development		0
Development and Construction in Progress		0
Total		123,079
Accumulated Depreciation		$ 45,550
Year(s) built / renovated		2,000
Year(s) Acquired		2,003
Depreciable Lives (Years)	[3]	(1)
Capital Gallery
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Capital Gallery
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		4,725
Original Building		29,565
Costs Capitalized Subsequent to Acquisition		89,028
Land and improvements		8,662
Buildings and Improvements		114,656
Land Held for Development		0
Development and Construction in Progress		0
Total		123,318
Accumulated Depreciation		$ 61,569
Year(s) built / renovated		1981/2006
Year(s) Acquired		2,007
Depreciable Lives (Years)	[3]	(1)
Two Freedom Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Two Freedom Square
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		13,930
Original Building		77,739
Costs Capitalized Subsequent to Acquisition		22,756
Land and improvements		15,420
Buildings and Improvements		99,005
Land Held for Development		0
Development and Construction in Progress		0
Total		114,425
Accumulated Depreciation		$ 44,569
Year(s) built / renovated		2,001
Year(s) Acquired		2,003
Depreciable Lives (Years)	[3]	(1)
One and Two Reston Overlook
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		One and Two Reston Overlook
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		16,456
Original Building		66,192
Costs Capitalized Subsequent to Acquisition		24,634
Land and improvements		16,179
Buildings and Improvements		91,103
Land Held for Development		0
Development and Construction in Progress		0
Total		107,282
Accumulated Depreciation		$ 40,513
Year(s) built / renovated		1,999
Year(s) Acquired		2,000
Depreciable Lives (Years)	[3]	(1)
Discovery Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Discovery Square
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		11,198
Original Building		71,782
Costs Capitalized Subsequent to Acquisition		22,642
Land and improvements		12,533
Buildings and Improvements		93,089
Land Held for Development		0
Development and Construction in Progress		0
Total		105,622
Accumulated Depreciation		$ 39,605
Year(s) built / renovated		2,001
Year(s) Acquired		2,003
Depreciable Lives (Years)	[3]	(1)
355 Main Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		355 Main Street
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		18,863
Original Building		53,346
Costs Capitalized Subsequent to Acquisition		27,658
Land and improvements		21,173
Buildings and Improvements		78,694
Land Held for Development		0
Development and Construction in Progress		0
Total		99,867
Accumulated Depreciation		$ 25,345
Year(s) built / renovated		1981/1996/2013
Year(s) Acquired		2,006
Depreciable Lives (Years)	[3]	(1)
140 Kendrick Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		140 Kendrick Street
Type		Office
Location		Needham, MA
Encumbrances		$ 0
Original Land		18,095
Original Building		66,905
Costs Capitalized Subsequent to Acquisition		15,466
Land and improvements		19,092
Buildings and Improvements		81,374
Land Held for Development		0
Development and Construction in Progress		0
Total		100,466
Accumulated Depreciation		$ 26,141
Year(s) built / renovated		2,000
Year(s) Acquired		2,004
Depreciable Lives (Years)	[3]	(1)
90 Broadway
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		90 Broadway
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		19,104
Original Building		52,078
Costs Capitalized Subsequent to Acquisition		17,048
Land and improvements		20,785
Buildings and Improvements		67,445
Land Held for Development		0
Development and Construction in Progress		0
Total		88,230
Accumulated Depreciation		$ 17,087
Year(s) built / renovated		1983/1998/2013
Year(s) Acquired		2,006
Depreciable Lives (Years)	[3]	(1)
10 CityPoint
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		10 CityPoint
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		1,953
Original Building		85,752
Costs Capitalized Subsequent to Acquisition		163
Land and improvements		2,116
Buildings and Improvements		85,752
Land Held for Development		0
Development and Construction in Progress		0
Total		87,868
Accumulated Depreciation		$ 1,601
Year(s) built / renovated		2,016
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
230 CityPoint
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		230 CityPoint
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		13,189
Original Building		49,823
Costs Capitalized Subsequent to Acquisition		20,187
Land and improvements		13,593
Buildings and Improvements		69,606
Land Held for Development		0
Development and Construction in Progress		0
Total		83,199
Accumulated Depreciation		$ 23,437
Year(s) built / renovated		1,992
Year(s) Acquired		2,005
Depreciable Lives (Years)	[3]	(1)
77 CityPoint
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		77 CityPoint
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		13,847
Original Building		60,383
Costs Capitalized Subsequent to Acquisition		5,703
Land and improvements		13,873
Buildings and Improvements		66,060
Land Held for Development		0
Development and Construction in Progress		0
Total		79,933
Accumulated Depreciation		$ 20,981
Year(s) built / renovated		2,008
Year(s) Acquired		2,001
Depreciable Lives (Years)	[3]	(1)
Waltham Weston Corporate Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Waltham Weston Corporate Center
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		10,385
Original Building		60,694
Costs Capitalized Subsequent to Acquisition		10,889
Land and improvements		11,097
Buildings and Improvements		70,871
Land Held for Development		0
Development and Construction in Progress		0
Total		81,968
Accumulated Depreciation		$ 27,310
Year(s) built / renovated		2,003
Year(s) Acquired		1,999
Depreciable Lives (Years)	[3]	(1)
3625-3635 Peterson Way
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		3625-3635 Peterson Way
Type		Office
Location		Santa Clara, CA
Encumbrances		$ 0
Original Land		63,206
Original Building		14,879
Costs Capitalized Subsequent to Acquisition		31
Land and improvements		63,206
Buildings and Improvements		14,879
Land Held for Development		31
Development and Construction in Progress		0
Total		78,116
Accumulated Depreciation		$ 2,093
Year(s) built / renovated		1,979
Year(s) Acquired		2,016
Depreciable Lives (Years)	[3]	(1)
North First Business Park
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		North First Business Park
Type		Office
Location		San Jose, CA
Encumbrances		$ 0
Original Land		58,402
Original Building		13,069
Costs Capitalized Subsequent to Acquisition		3,932
Land and improvements		23,377
Buildings and Improvements		16,116
Land Held for Development		35,910
Development and Construction in Progress		0
Total		75,403
Accumulated Depreciation		$ 15,811
Year(s) built / renovated		1,981
Year(s) Acquired		2,007
Depreciable Lives (Years)	[3]	(1)
2440 West El Camino Real
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		2440 West El Camino Real
Type		Office
Location		Mountain View, CA
Encumbrances		$ 0
Original Land		16,741
Original Building		51,285
Costs Capitalized Subsequent to Acquisition		1,814
Land and improvements		16,741
Buildings and Improvements		53,099
Land Held for Development		0
Development and Construction in Progress		0
Total		69,840
Accumulated Depreciation		$ 9,817
Year(s) built / renovated		1987/2003
Year(s) Acquired		2,011
Depreciable Lives (Years)	[3]	(1)
300 Binney Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		300 Binney Street
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		18,080
Original Building		51,262
Costs Capitalized Subsequent to Acquisition		140
Land and improvements		18,080
Buildings and Improvements		51,402
Land Held for Development		0
Development and Construction in Progress		0
Total		69,482
Accumulated Depreciation		$ 6,059
Year(s) built / renovated		2,013
Year(s) Acquired		2,009
Depreciable Lives (Years)	[3]	(1)
Reston Corporate Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Reston Corporate Center
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		9,135
Original Building		50,857
Costs Capitalized Subsequent to Acquisition		6,256
Land and improvements		10,148
Buildings and Improvements		56,100
Land Held for Development		0
Development and Construction in Progress		0
Total		66,248
Accumulated Depreciation		$ 25,244
Year(s) built / renovated		1,984
Year(s) Acquired		1,998
Depreciable Lives (Years)	[3]	(1)
Wisconsin Place
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Wisconsin Place
Type		Office
Location		Chevy Chase, MD
Encumbrances		$ 0
Original Land		0
Original Building		53,349
Costs Capitalized Subsequent to Acquisition		9,884
Land and improvements		0
Buildings and Improvements		63,233
Land Held for Development		0
Development and Construction in Progress		0
Total		63,233
Accumulated Depreciation		$ 16,406
Year(s) built / renovated		2,009
Year(s) Acquired		2,004
Depreciable Lives (Years)	[3]	(1)
New Dominion Technology Park, Bldg. Two
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		New Dominion Technology Park, Bldg. Two
Type		Office
Location		Herndon, VA
Encumbrances		$ 0
Original Land		5,584
Original Building		51,868
Costs Capitalized Subsequent to Acquisition		4,094
Land and improvements		6,510
Buildings and Improvements		55,036
Land Held for Development		0
Development and Construction in Progress		0
Total		61,546
Accumulated Depreciation		$ 21,908
Year(s) built / renovated		2,004
Year(s) Acquired		1,998
Depreciable Lives (Years)	[3]	(1)
200 West Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		200 West Street
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		16,148
Original Building		24,983
Costs Capitalized Subsequent to Acquisition		10,102
Land and improvements		16,813
Buildings and Improvements		34,420
Land Held for Development		0
Development and Construction in Progress		0
Total		51,233
Accumulated Depreciation		$ 19,535
Year(s) built / renovated		1,999
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
New Dominion Technology Park, Bldg. One
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		New Dominion Technology Park, Bldg. One
Type		Office
Location		Herndon, VA
Encumbrances		$ 35,485
Original Land		3,880
Original Building		43,227
Costs Capitalized Subsequent to Acquisition		3,883
Land and improvements		4,583
Buildings and Improvements		46,407
Land Held for Development		0
Development and Construction in Progress		0
Total		50,990
Accumulated Depreciation		$ 24,362
Year(s) built / renovated		2,001
Year(s) Acquired		1,998
Depreciable Lives (Years)	[3]	(1)
Sumner Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Sumner Square
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		624
Original Building		28,745
Costs Capitalized Subsequent to Acquisition		19,428
Land and improvements		1,478
Buildings and Improvements		47,319
Land Held for Development		0
Development and Construction in Progress		0
Total		48,797
Accumulated Depreciation		$ 22,237
Year(s) built / renovated		1,985
Year(s) Acquired		1,999
Depreciable Lives (Years)	[3]	(1)
University Place
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		University Place
Type		Office
Location		Cambridge, MA
Encumbrances		$ 9,119
Original Land		0
Original Building		37,091
Costs Capitalized Subsequent to Acquisition		9,501
Land and improvements		390
Buildings and Improvements		46,202
Land Held for Development		0
Development and Construction in Progress		0
Total		46,592
Accumulated Depreciation		$ 25,207
Year(s) built / renovated		1,985
Year(s) Acquired		1,998
Depreciable Lives (Years)	[3]	(1)
2600 Tower Oaks Boulevard
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		2600 Tower Oaks Boulevard
Type		Office
Location		Rockville, MD
Encumbrances		$ 0
Original Land		4,243
Original Building		31,125
Costs Capitalized Subsequent to Acquisition		9,081
Land and improvements		4,785
Buildings and Improvements		39,664
Land Held for Development		0
Development and Construction in Progress		0
Total		44,449
Accumulated Depreciation		$ 19,801
Year(s) built / renovated		2,001
Year(s) Acquired		1,998
Depreciable Lives (Years)	[3]	(1)
255 Main Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		255 Main Street
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		134
Original Building		25,110
Costs Capitalized Subsequent to Acquisition		17,087
Land and improvements		548
Buildings and Improvements		41,783
Land Held for Development		0
Development and Construction in Progress		0
Total		42,331
Accumulated Depreciation		$ 27,499
Year(s) built / renovated		1,987
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
Quorum Office Park
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Quorum Office Park
Type		Office
Location		Chelmsford, MA
Encumbrances		$ 0
Original Land		3,750
Original Building		32,454
Costs Capitalized Subsequent to Acquisition		5,813
Land and improvements		5,187
Buildings and Improvements		36,830
Land Held for Development		0
Development and Construction in Progress		0
Total		42,017
Accumulated Depreciation		$ 15,633
Year(s) built / renovated		2,001
Year(s) Acquired		2,000
Depreciable Lives (Years)	[3]	(1)
150 Broadway
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		150 Broadway
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		850
Original Building		25,042
Costs Capitalized Subsequent to Acquisition		8,623
Land and improvements		1,323
Buildings and Improvements		33,192
Land Held for Development		0
Development and Construction in Progress		0
Total		34,515
Accumulated Depreciation		$ 15,545
Year(s) built / renovated		1,999
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
500 E Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		500 E Street
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		109
Original Building		22,420
Costs Capitalized Subsequent to Acquisition		13,219
Land and improvements		2,379
Buildings and Improvements		33,369
Land Held for Development		0
Development and Construction in Progress		0
Total		35,748
Accumulated Depreciation		$ 22,987
Year(s) built / renovated		1,987
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
325 Main Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		325 Main Street
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		174
Original Building		12,200
Costs Capitalized Subsequent to Acquisition		12,256
Land and improvements		965
Buildings and Improvements		23,665
Land Held for Development		0
Development and Construction in Progress		0
Total		24,630
Accumulated Depreciation		$ 12,266
Year(s) built / renovated		1987/2013
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
105 Broadway
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		105 Broadway
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		1,299
Original Building		12,943
Costs Capitalized Subsequent to Acquisition		7,198
Land and improvements		2,395
Buildings and Improvements		19,045
Land Held for Development		0
Development and Construction in Progress		0
Total		21,440
Accumulated Depreciation		$ 13,018
Year(s) built / renovated		1,990
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
Lexington Office Park
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Lexington Office Park
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		998
Original Building		1,426
Costs Capitalized Subsequent to Acquisition		17,481
Land and improvements		1,264
Buildings and Improvements		18,641
Land Held for Development		0
Development and Construction in Progress		0
Total		19,905
Accumulated Depreciation		$ 12,490
Year(s) built / renovated		1,982
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
40 Shattuck Road
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		40 Shattuck Road
Type		Office
Location		Andover, MA
Encumbrances		$ 0
Original Land		709
Original Building		14,740
Costs Capitalized Subsequent to Acquisition		3,368
Land and improvements		893
Buildings and Improvements		17,924
Land Held for Development		0
Development and Construction in Progress		0
Total		18,817
Accumulated Depreciation		$ 7,505
Year(s) built / renovated		2,001
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
201 Spring Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		201 Spring Street
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		2,849
Original Building		15,303
Costs Capitalized Subsequent to Acquisition		14
Land and improvements		3,124
Buildings and Improvements		15,042
Land Held for Development		0
Development and Construction in Progress		0
Total		18,166
Accumulated Depreciation		$ 7,462
Year(s) built / renovated		1,997
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
The Point
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		The Point
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		6,395
Original Building		10,040
Costs Capitalized Subsequent to Acquisition		408
Land and improvements		6,480
Buildings and Improvements		10,363
Land Held for Development		0
Development and Construction in Progress		0
Total		16,843
Accumulated Depreciation		$ 397
Year(s) built / renovated		2,015
Year(s) Acquired		2,007
Depreciable Lives (Years)	[3]	(1)
690 Folsom Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		690 Folsom Street
Type		Office
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		3,219
Original Building		11,038
Costs Capitalized Subsequent to Acquisition		1,157
Land and improvements		3,219
Buildings and Improvements		12,195
Land Held for Development		0
Development and Construction in Progress		0
Total		15,414
Accumulated Depreciation		$ 801
Year(s) built / renovated		2,015
Year(s) Acquired		2,012
Depreciable Lives (Years)	[3]	(1)
91 Hartwell Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		91 Hartwell Avenue
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		784
Original Building		6,464
Costs Capitalized Subsequent to Acquisition		8,254
Land and improvements		941
Buildings and Improvements		14,561
Land Held for Development		0
Development and Construction in Progress		0
Total		15,502
Accumulated Depreciation		$ 9,062
Year(s) built / renovated		1,985
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
92-100 Hayden Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		92-100 Hayden Avenue
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		594
Original Building		6,748
Costs Capitalized Subsequent to Acquisition		8,181
Land and improvements		802
Buildings and Improvements		14,721
Land Held for Development		0
Development and Construction in Progress		0
Total		15,523
Accumulated Depreciation		$ 12,062
Year(s) built / renovated		1,985
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
181 Spring Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		181 Spring Street
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		1,066
Original Building		9,520
Costs Capitalized Subsequent to Acquisition		2,195
Land and improvements		1,160
Buildings and Improvements		11,621
Land Held for Development		0
Development and Construction in Progress		0
Total		12,781
Accumulated Depreciation		$ 4,876
Year(s) built / renovated		1,999
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
145 Broadway
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		145 Broadway
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		121
Original Building		5,535
Costs Capitalized Subsequent to Acquisition		7,173
Land and improvements		324
Buildings and Improvements		10,637
Land Held for Development		0
Development and Construction in Progress		1,868
Total		12,829
Accumulated Depreciation		$ 8,676
Year(s) built / renovated		1,984
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
33 Hayden Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		33 Hayden Avenue
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		266
Original Building		3,234
Costs Capitalized Subsequent to Acquisition		8,787
Land and improvements		425
Buildings and Improvements		11,862
Land Held for Development		0
Development and Construction in Progress		0
Total		12,287
Accumulated Depreciation		$ 7,612
Year(s) built / renovated		1,979
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
195 West Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		195 West Street
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		1,611
Original Building		6,652
Costs Capitalized Subsequent to Acquisition		4,340
Land and improvements		1,858
Buildings and Improvements		10,745
Land Held for Development		0
Development and Construction in Progress		0
Total		12,603
Accumulated Depreciation		$ 7,517
Year(s) built / renovated		1,990
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
7501 Boston Boulevard, Building Seven
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7501 Boston Boulevard, Building Seven
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		665
Original Building		9,273
Costs Capitalized Subsequent to Acquisition		535
Land and improvements		791
Buildings and Improvements		9,682
Land Held for Development		0
Development and Construction in Progress		0
Total		10,473
Accumulated Depreciation		$ 4,596
Year(s) built / renovated		1,997
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
7435 Boston Boulevard, Building One
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7435 Boston Boulevard, Building One
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		392
Original Building		3,822
Costs Capitalized Subsequent to Acquisition		5,116
Land and improvements		659
Buildings and Improvements		8,671
Land Held for Development		0
Development and Construction in Progress		0
Total		9,330
Accumulated Depreciation		$ 6,356
Year(s) built / renovated		1,982
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
250 Binney Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		250 Binney Street
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		110
Original Building		4,483
Costs Capitalized Subsequent to Acquisition		3,593
Land and improvements		273
Buildings and Improvements		7,913
Land Held for Development		0
Development and Construction in Progress		0
Total		8,186
Accumulated Depreciation		$ 4,684
Year(s) built / renovated		1,983
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
7450 Boston Boulevard, Building Three
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7450 Boston Boulevard, Building Three
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		1,165
Original Building		4,681
Costs Capitalized Subsequent to Acquisition		1,807
Land and improvements		1,430
Buildings and Improvements		6,223
Land Held for Development		0
Development and Construction in Progress		0
Total		7,653
Accumulated Depreciation		$ 3,321
Year(s) built / renovated		1,987
Year(s) Acquired		1,998
Depreciable Lives (Years)	[3]	(1)
453 Ravendale Drive
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		453 Ravendale Drive
Type		Office
Location		Mountain View, CA
Encumbrances		$ 0
Original Land		5,477
Original Building		1,090
Costs Capitalized Subsequent to Acquisition		408
Land and improvements		5,477
Buildings and Improvements		1,498
Land Held for Development		0
Development and Construction in Progress		0
Total		6,975
Accumulated Depreciation		$ 338
Year(s) built / renovated		1,977
Year(s) Acquired		2,012
Depreciable Lives (Years)	[3]	(1)
8000 Grainger Court, Building Five
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		8000 Grainger Court, Building Five
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		366
Original Building		4,282
Costs Capitalized Subsequent to Acquisition		2,607
Land and improvements		601
Buildings and Improvements		6,654
Land Held for Development		0
Development and Construction in Progress		0
Total		7,255
Accumulated Depreciation		$ 5,416
Year(s) built / renovated		1,984
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
17 Hartwell Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		17 Hartwell Avenue
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		26
Original Building		150
Costs Capitalized Subsequent to Acquisition		6,109
Land and improvements		65
Buildings and Improvements		6,220
Land Held for Development		0
Development and Construction in Progress		0
Total		6,285
Accumulated Depreciation		$ 552
Year(s) built / renovated		1,968
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
7300 Boston Boulevard, Building Thirteen
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7300 Boston Boulevard, Building Thirteen
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		608
Original Building		4,773
Costs Capitalized Subsequent to Acquisition		709
Land and improvements		661
Buildings and Improvements		5,429
Land Held for Development		0
Development and Construction in Progress		0
Total		6,090
Accumulated Depreciation		$ 5,012
Year(s) built / renovated		2,002
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
7500 Boston Boulevard, Building Six
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7500 Boston Boulevard, Building Six
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		138
Original Building		3,749
Costs Capitalized Subsequent to Acquisition		2,487
Land and improvements		406
Buildings and Improvements		5,968
Land Held for Development		0
Development and Construction in Progress		0
Total		6,374
Accumulated Depreciation		$ 4,538
Year(s) built / renovated		1,985
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
7601 Boston Boulevard, Building Eight
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7601 Boston Boulevard, Building Eight
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		200
Original Building		878
Costs Capitalized Subsequent to Acquisition		5,047
Land and improvements		551
Buildings and Improvements		5,574
Land Held for Development		0
Development and Construction in Progress		0
Total		6,125
Accumulated Depreciation		$ 4,043
Year(s) built / renovated		1,986
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
8000 Corporate Court, Building Eleven
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		8000 Corporate Court, Building Eleven
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		136
Original Building		3,071
Costs Capitalized Subsequent to Acquisition		1,615
Land and improvements		775
Buildings and Improvements		4,047
Land Held for Development		0
Development and Construction in Progress		0
Total		4,822
Accumulated Depreciation		$ 2,784
Year(s) built / renovated		1,989
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
7375 Boston Boulevard, Building Ten
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7375 Boston Boulevard, Building Ten
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		23
Original Building		2,685
Costs Capitalized Subsequent to Acquisition		912
Land and improvements		93
Buildings and Improvements		3,527
Land Held for Development		0
Development and Construction in Progress		0
Total		3,620
Accumulated Depreciation		$ 2,472
Year(s) built / renovated		1,988
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
7374 Boston Boulevard, Building Four
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7374 Boston Boulevard, Building Four
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		241
Original Building		1,605
Costs Capitalized Subsequent to Acquisition		1,738
Land and improvements		398
Buildings and Improvements		3,186
Land Held for Development		0
Development and Construction in Progress		0
Total		3,584
Accumulated Depreciation		$ 2,452
Year(s) built / renovated		1,984
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
7451 Boston Boulevard, Building Two
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7451 Boston Boulevard, Building Two
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		249
Original Building		1,542
Costs Capitalized Subsequent to Acquisition		1,659
Land and improvements		613
Buildings and Improvements		2,837
Land Held for Development		0
Development and Construction in Progress		0
Total		3,450
Accumulated Depreciation		$ 2,330
Year(s) built / renovated		1,982
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
32 Hartwell Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		32 Hartwell Avenue
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		168
Original Building		1,943
Costs Capitalized Subsequent to Acquisition		1,012
Land and improvements		314
Buildings and Improvements		2,809
Land Held for Development		0
Development and Construction in Progress		0
Total		3,123
Accumulated Depreciation		$ 1,905
Year(s) built / renovated		1968/1979/1987
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
164 Lexington Road
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		164 Lexington Road
Type		Office
Location		Billerica, MA
Encumbrances		$ 0
Original Land		592
Original Building		1,370
Costs Capitalized Subsequent to Acquisition		319
Land and improvements		643
Buildings and Improvements		1,638
Land Held for Development		0
Development and Construction in Progress		0
Total		2,281
Accumulated Depreciation		$ 827
Year(s) built / renovated		1,982
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
The Avant at Reston Town Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		The Avant at Reston Town Center
Type		Residential
Location		Reston, VA
Encumbrances		$ 0
Original Land		20,350
Original Building		91,995
Costs Capitalized Subsequent to Acquisition		815
Land and improvements		20,350
Buildings and Improvements		92,810
Land Held for Development		0
Development and Construction in Progress		0
Total		113,160
Accumulated Depreciation		$ 7,306
Year(s) built / renovated		2,014
Year(s) Acquired		2,010
Depreciable Lives (Years)	[3]	(1)
The Lofts at Atlantic Wharf
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		The Lofts at Atlantic Wharf
Type		Residential
Location		Boston, MA
Encumbrances		$ 0
Original Land		3,529
Original Building		54,891
Costs Capitalized Subsequent to Acquisition		1,663
Land and improvements		3,529
Buildings and Improvements		56,554
Land Held for Development		0
Development and Construction in Progress		0
Total		60,083
Accumulated Depreciation		$ 8,105
Year(s) built / renovated		2,011
Year(s) Acquired		2,007
Depreciable Lives (Years)	[3]	(1)
Boston Marriott Cambridge
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Boston Marriott Cambridge
Type		Hotel
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		478
Original Building		37,918
Costs Capitalized Subsequent to Acquisition		37,067
Land and improvements		1,201
Buildings and Improvements		74,262
Land Held for Development		0
Development and Construction in Progress		0
Total		75,463
Accumulated Depreciation		$ 50,954
Year(s) built / renovated		1,986
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
Kendall Center Green Garage
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Green Garage
Type		Garage
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		0
Original Building		35,035
Costs Capitalized Subsequent to Acquisition		7,391
Land and improvements		103
Buildings and Improvements		42,323
Land Held for Development		0
Development and Construction in Progress		0
Total		42,426
Accumulated Depreciation		$ 9,334
Year(s) built / renovated		1,984
Year(s) Acquired		2,006
Depreciable Lives (Years)	[3]	(1)
Kendall Center Yellow Garage
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Yellow Garage
Type		Garage
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		1,256
Original Building		15,697
Costs Capitalized Subsequent to Acquisition		1,571
Land and improvements		1,434
Buildings and Improvements		17,090
Land Held for Development		0
Development and Construction in Progress		0
Total		18,524
Accumulated Depreciation		$ 4,723
Year(s) built / renovated		2,006
Year(s) Acquired		2,004
Depreciable Lives (Years)	[3]	(1)
Kendall Center Blue Garage
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Blue Garage
Type		Garage
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		1,163
Original Building		11,633
Costs Capitalized Subsequent to Acquisition		2,770
Land and improvements		1,579
Buildings and Improvements		13,987
Land Held for Development		0
Development and Construction in Progress		0
Total		15,566
Accumulated Depreciation		$ 9,325
Year(s) built / renovated		1,990
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
Salesforce Tower
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Salesforce Tower
Type		Development
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		723,866
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		0
Development and Construction in Progress		723,866
Total		723,866
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,013
Depreciable Lives (Years)		N/A
Signature at Reston (formerly Reston Signature Site)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Signature at Reston (formerly Reston Signature Site)
Type		Development
Location		Reston, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		96,444
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		0
Development and Construction in Progress		96,444
Total		96,444
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,013
Depreciable Lives (Years)		N/A
191 Spring Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		191 Spring Street
Type		Development
Location		Lexington, MA
Encumbrances		$ 0
Original Land		2,850
Original Building		27,166
Costs Capitalized Subsequent to Acquisition		3,134
Land and improvements		3,151
Buildings and Improvements		28,576
Land Held for Development		0
Development and Construction in Progress		1,423
Total		33,150
Accumulated Depreciation		$ 21,660
Year(s) built / renovated		1971/1995
Year(s) Acquired		1,997
Depreciable Lives (Years)	[3]	(1)
Proto at Cambridge (formerly Cambridge Residential / 88 Ames)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Proto at Cambridge (formerly Cambridge Residential / 88 Ames)
Type		Development
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		24,334
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		0
Development and Construction in Progress		24,334
Total		24,334
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,015
Depreciable Lives (Years)		N/A
Springfield Metro Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Springfield Metro Center
Type		Land
Location		Springfield, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		35,430
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		35,430
Development and Construction in Progress		0
Total		35,430
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,007
Depreciable Lives (Years)		N/A
Tower Oaks Master Plan
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Tower Oaks Master Plan
Type		Land
Location		Rockville, MD
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		29,209
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		29,209
Development and Construction in Progress		0
Total		29,209
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		1,998
Depreciable Lives (Years)		N/A
Plaza at Almaden
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Plaza at Almaden
Type		Land
Location		San Jose, CA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		29,081
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		29,081
Development and Construction in Progress		0
Total		29,081
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,006
Depreciable Lives (Years)		N/A
6601 & 6605 Springfield Center Drive
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		6601 & 6605 Springfield Center Drive
Type		Land
Location		Springfield, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		13,866
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		13,866
Development and Construction in Progress		0
Total		13,866
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,007
Depreciable Lives (Years)		N/A
214 Third Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		214 Third Avenue
Type		Land
Location		Waltham, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		13,795
Land and improvements		0
Buildings and Improvements		146
Land Held for Development		13,649
Development and Construction in Progress		0
Total		13,795
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,006
Depreciable Lives (Years)		N/A
103 Fourth Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		103 Fourth Avenue
Type		Land
Location		Waltham, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		12,052
Land and improvements		0
Buildings and Improvements		49
Land Held for Development		12,003
Development and Construction in Progress		0
Total		12,052
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,007
Depreciable Lives (Years)		N/A
20 CityPoint
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		20 CityPoint
Type		Land
Location		Waltham, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		11,666
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		11,666
Development and Construction in Progress		0
Total		11,666
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,007
Depreciable Lives (Years)		N/A
Reston Gateway
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Reston Gateway
Type		Land
Location		Reston, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		10,841
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		10,841
Development and Construction in Progress		0
Total		10,841
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		1,998
Depreciable Lives (Years)		N/A
Reston Eastgate
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Reston Eastgate
Type		Land
Location		Reston, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		9,906
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		9,906
Development and Construction in Progress		0
Total		9,906
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,001
Depreciable Lives (Years)		N/A
Crane Meadow
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Crane Meadow
Type		Land
Location		Marlborough, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		8,754
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		8,754
Development and Construction in Progress		0
Total		8,754
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,000
Depreciable Lives (Years)		N/A
Washingtonian North
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Washingtonian North
Type		Land
Location		Gaithersburg, MD
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		7,697
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		7,697
Development and Construction in Progress		0
Total		7,697
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		1,998
Depreciable Lives (Years)		N/A
Kendall Center Master Plan
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Master Plan
Type		Land
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		4,062
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		4,062
Development and Construction in Progress		0
Total		4,062
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		N/A
Depreciable Lives (Years)		N/A
Fourth and Harrison
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Fourth and Harrison
Type		Land
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		3,936
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		3,936
Development and Construction in Progress		0
Total		3,936
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		N/A
Depreciable Lives (Years)		N/A
North First Master Plan
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		North First Master Plan
Type		Land
Location		San Jose, CA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		3,014
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		3,014
Development and Construction in Progress		0
Total		3,014
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,007
Depreciable Lives (Years)		N/A
Broad Run Business Park
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Broad Run Business Park
Type		Land
Location		Loudoun County, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		2,694
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		2,694
Development and Construction in Progress		0
Total		2,694
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		1,998
Depreciable Lives (Years)		N/A
MacArthur Station
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		MacArthur Station
Type		Land
Location		Oakland, CA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		1,316
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		1,316
Development and Construction in Progress		0
Total		1,316
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		N/A
Depreciable Lives (Years)		N/A
30 Shattuck Road
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		30 Shattuck Road
Type		Land
Location		Andover, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		1,214
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		1,214
Development and Construction in Progress		0
Total		1,214
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		1,997
Depreciable Lives (Years)		N/A
2100 Pennsylvania Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		2100 Pennsylvania Avenue
Type		Land
Location		Washington, DC
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		286
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		286
Development and Construction in Progress		0
Total		286
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	[4]	$ 2,063,087
Original Land		4,759,821
Original Building		11,416,957
Costs Capitalized Subsequent to Acquisition		3,524,407
Land and improvements		4,774,460
Buildings and Improvements		13,642,110
Land Held for Development	[5]	246,656
Development and Construction in Progress		1,037,959
Total		19,701,185
Accumulated Depreciation		4,116,020
Furniture, fixtures and equipment		32,687	$ 29,852
Furniture, fixtures and equipment accumulated depreciation		20,344
Real Estate Aggregate Cost For Tax Purposes		17,600,000
Real Estate Aggregate Accumulated Depreciation For Tax Purposes		$ 3,600,000
Real Estate and Accumulated Depreciation, Life Used for Depreciation		40 years
Unamortized balance of historical fair value adjustments		$ 33,800
Unamortized deferred finance costs		$ (2,400)
Boston Properties Limited Partnership | 767 Fifth Avenue (the General Motors Building)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		767 Fifth Avenue (the General Motors Building)
Type		Office
Location		New York, NY
Encumbrances		$ 1,333,625
Original Land		1,796,252
Original Building		1,532,654
Costs Capitalized Subsequent to Acquisition		75,211
Land and improvements		1,796,252
Buildings and Improvements		1,607,865
Land Held for Development		0
Development and Construction in Progress		0
Total		3,404,117
Accumulated Depreciation		$ 189,209
Year(s) built / renovated		1,968
Year(s) Acquired		2,013
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Prudential Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Prudential Center
Type		Office
Location		Boston, MA
Encumbrances		$ 0
Original Land		92,077
Original Building		734,594
Costs Capitalized Subsequent to Acquisition		596,236
Land and improvements		100,540
Buildings and Improvements		1,169,515
Land Held for Development		0
Development and Construction in Progress		152,852
Total		1,422,907
Accumulated Depreciation		$ 470,161
Year(s) built / renovated		1965/1993/2002/2016
Year(s) Acquired		1998/1999/2000
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Embarcadero Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Embarcadero Center
Type		Office
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		179,697
Original Building		847,410
Costs Capitalized Subsequent to Acquisition		281,345
Land and improvements		180,420
Buildings and Improvements		1,128,032
Land Held for Development		0
Development and Construction in Progress		0
Total		1,308,452
Accumulated Depreciation		$ 547,434
Year(s) built / renovated		1970/1989
Year(s) Acquired		1998-1999
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 399 Park Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		399 Park Avenue
Type		Office
Location		New York, NY
Encumbrances		$ 0
Original Land		339,200
Original Building		700,358
Costs Capitalized Subsequent to Acquisition		72,454
Land and improvements		339,200
Buildings and Improvements		772,812
Land Held for Development		0
Development and Construction in Progress		0
Total		1,112,012
Accumulated Depreciation		$ 275,380
Year(s) built / renovated		1,961
Year(s) Acquired		2,002
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 200 Clarendon Street and Garage
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		200 Clarendon Street and Garage
Type		Office
Location		Boston, MA
Encumbrances		$ 0
Original Land		219,543
Original Building		667,884
Costs Capitalized Subsequent to Acquisition		115,996
Land and improvements		219,616
Buildings and Improvements		777,557
Land Held for Development		6,250
Development and Construction in Progress		0
Total		1,003,423
Accumulated Depreciation		$ 140,629
Year(s) built / renovated		1,976
Year(s) Acquired		2,010
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 250 West 55th Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		250 West 55th Street
Type		Office
Location		New York, NY
Encumbrances		$ 0
Original Land		285,263
Original Building		603,167
Costs Capitalized Subsequent to Acquisition		35,668
Land and improvements		285,263
Buildings and Improvements		638,835
Land Held for Development		0
Development and Construction in Progress		0
Total		924,098
Accumulated Depreciation		$ 49,852
Year(s) built / renovated		2,014
Year(s) Acquired		2,007
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 601 Lexington Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		601 Lexington Avenue
Type		Office
Location		New York, NY
Encumbrances		$ 684,858
Original Land		241,600
Original Building		494,782
Costs Capitalized Subsequent to Acquisition		159,273
Land and improvements		279,281
Buildings and Improvements		593,759
Land Held for Development		0
Development and Construction in Progress		22,615
Total		895,655
Accumulated Depreciation		$ 232,590
Year(s) built / renovated		1977/1997
Year(s) Acquired		2,001
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Carnegie Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Carnegie Center
Type		Office
Location		Princeton, NJ
Encumbrances		$ 0
Original Land		105,107
Original Building		377,259
Costs Capitalized Subsequent to Acquisition		132,258
Land and improvements		102,403
Buildings and Improvements		509,667
Land Held for Development		2,554
Development and Construction in Progress		0
Total		614,624
Accumulated Depreciation		$ 207,448
Year(s) built / renovated		1983-2016
Year(s) Acquired		1998/1999/2000/2007/2014
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 100 Federal Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		100 Federal Street
Type		Office
Location		Boston, MA
Encumbrances		$ 0
Original Land		131,067
Original Building		435,954
Costs Capitalized Subsequent to Acquisition		38,611
Land and improvements		131,067
Buildings and Improvements		474,565
Land Held for Development		0
Development and Construction in Progress		0
Total		605,632
Accumulated Depreciation		$ 77,409
Year(s) built / renovated		1971-1975
Year(s) Acquired		2,012
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Times Square Tower
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Times Square Tower
Type		Office
Location		New York, NY
Encumbrances		$ 0
Original Land		165,413
Original Building		380,438
Costs Capitalized Subsequent to Acquisition		49,604
Land and improvements		159,694
Buildings and Improvements		435,761
Land Held for Development		0
Development and Construction in Progress		0
Total		595,455
Accumulated Depreciation		$ 171,039
Year(s) built / renovated		2,004
Year(s) Acquired		2,000
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Atlantic Wharf
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Atlantic Wharf
Type		Office
Location		Boston, MA
Encumbrances		$ 0
Original Land		63,988
Original Building		454,537
Costs Capitalized Subsequent to Acquisition		17,442
Land and improvements		63,988
Buildings and Improvements		471,979
Land Held for Development		0
Development and Construction in Progress		0
Total		535,967
Accumulated Depreciation		$ 85,984
Year(s) built / renovated		2,011
Year(s) Acquired		2,007
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Fountain Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Fountain Square
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		56,853
Original Building		306,298
Costs Capitalized Subsequent to Acquisition		17,748
Land and improvements		56,853
Buildings and Improvements		320,759
Land Held for Development		3,287
Development and Construction in Progress		0
Total		380,899
Accumulated Depreciation		$ 50,106
Year(s) built / renovated		1986-1990
Year(s) Acquired		2,012
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 510 Madison Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		510 Madison Avenue
Type		Office
Location		New York, NY
Encumbrances		$ 0
Original Land		103,000
Original Building		253,665
Costs Capitalized Subsequent to Acquisition		21,952
Land and improvements		103,000
Buildings and Improvements		275,617
Land Held for Development		0
Development and Construction in Progress		0
Total		378,617
Accumulated Depreciation		$ 44,515
Year(s) built / renovated		2,012
Year(s) Acquired		2,010
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 599 Lexington Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		599 Lexington Avenue
Type		Office
Location		New York, NY
Encumbrances		$ 0
Original Land		81,040
Original Building		100,507
Costs Capitalized Subsequent to Acquisition		141,980
Land and improvements		81,040
Buildings and Improvements		242,487
Land Held for Development		0
Development and Construction in Progress		0
Total		323,527
Accumulated Depreciation		$ 163,140
Year(s) built / renovated		1,986
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 680 Folsom Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		680 Folsom Street
Type		Office
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		72,545
Original Building		219,766
Costs Capitalized Subsequent to Acquisition		7,352
Land and improvements		72,545
Buildings and Improvements		227,118
Land Held for Development		0
Development and Construction in Progress		0
Total		299,663
Accumulated Depreciation		$ 21,845
Year(s) built / renovated		2,014
Year(s) Acquired		2,012
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | South of Market and Democracy Tower
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		South of Market and Democracy Tower
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		13,603
Original Building		237,479
Costs Capitalized Subsequent to Acquisition		15,119
Land and improvements		13,603
Buildings and Improvements		252,598
Land Held for Development		0
Development and Construction in Progress		0
Total		266,201
Accumulated Depreciation		$ 79,814
Year(s) built / renovated		2008-2009
Year(s) Acquired		2,003
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 601 Massachusetts Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		601 Massachusetts Avenue
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		95,310
Original Building		165,173
Costs Capitalized Subsequent to Acquisition		0
Land and improvements		95,310
Buildings and Improvements		165,173
Land Held for Development		0
Development and Construction in Progress		0
Total		260,483
Accumulated Depreciation		$ 6,534
Year(s) built / renovated		2,016
Year(s) Acquired		2,008
Depreciable Lives (Years)		(1)
Boston Properties Limited Partnership | Bay Colony Corporate Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Bay Colony Corporate Center
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		18,789
Original Building		148,451
Costs Capitalized Subsequent to Acquisition		68,371
Land and improvements		18,789
Buildings and Improvements		216,822
Land Held for Development		0
Development and Construction in Progress		0
Total		235,611
Accumulated Depreciation		$ 46,015
Year(s) built / renovated		1985-1989
Year(s) Acquired		2,011
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Gateway Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Gateway Center
Type		Office
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		28,255
Original Building		139,245
Costs Capitalized Subsequent to Acquisition		49,291
Land and improvements		29,029
Buildings and Improvements		187,762
Land Held for Development		0
Development and Construction in Progress		0
Total		216,791
Accumulated Depreciation		$ 96,681
Year(s) built / renovated		1984/1986/2002
Year(s) Acquired		1,999
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 535 Mission Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		535 Mission Street
Type		Office
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		40,933
Original Building		148,378
Costs Capitalized Subsequent to Acquisition		2,015
Land and improvements		40,933
Buildings and Improvements		150,393
Land Held for Development		0
Development and Construction in Progress		0
Total		191,326
Accumulated Depreciation		$ 8,844
Year(s) built / renovated		2,015
Year(s) Acquired		2,013
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 2200 Pennsylvania Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		2200 Pennsylvania Avenue
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		0
Original Building		183,541
Costs Capitalized Subsequent to Acquisition		5,047
Land and improvements		0
Buildings and Improvements		188,588
Land Held for Development		0
Development and Construction in Progress		0
Total		188,588
Accumulated Depreciation		$ 39,956
Year(s) built / renovated		2,011
Year(s) Acquired		2,008
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Mountain View Research Park
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Mountain View Research Park
Type		Office
Location		Mountain View, CA
Encumbrances		$ 0
Original Land		95,066
Original Building		68,373
Costs Capitalized Subsequent to Acquisition		6,491
Land and improvements		95,066
Buildings and Improvements		74,864
Land Held for Development		0
Development and Construction in Progress		0
Total		169,930
Accumulated Depreciation		$ 12,849
Year(s) built / renovated		1977-1981/2007-2013
Year(s) Acquired		2,013
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Reservoir Place
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Reservoir Place
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		18,605
Original Building		92,619
Costs Capitalized Subsequent to Acquisition		49,088
Land and improvements		19,099
Buildings and Improvements		126,656
Land Held for Development		0
Development and Construction in Progress		14,557
Total		160,312
Accumulated Depreciation		$ 60,518
Year(s) built / renovated		1955/1987
Year(s) Acquired		1997/1998
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 1330 Connecticut Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		1330 Connecticut Avenue
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		25,982
Original Building		82,311
Costs Capitalized Subsequent to Acquisition		27,663
Land and improvements		25,982
Buildings and Improvements		109,974
Land Held for Development		0
Development and Construction in Progress		0
Total		135,956
Accumulated Depreciation		$ 33,179
Year(s) built / renovated		1,984
Year(s) Acquired		2,004
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Kingstowne Towne Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kingstowne Towne Center
Type		Office
Location		Alexandria, VA
Encumbrances		$ 0
Original Land		18,021
Original Building		109,038
Costs Capitalized Subsequent to Acquisition		919
Land and improvements		18,021
Buildings and Improvements		109,957
Land Held for Development		0
Development and Construction in Progress		0
Total		127,978
Accumulated Depreciation		$ 36,524
Year(s) built / renovated		2003-2006
Year(s) Acquired		2,007
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 1333 New Hampshire Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		1333 New Hampshire Avenue
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		34,032
Original Building		85,660
Costs Capitalized Subsequent to Acquisition		5,753
Land and improvements		34,032
Buildings and Improvements		91,413
Land Held for Development		0
Development and Construction in Progress		0
Total		125,445
Accumulated Depreciation		$ 36,878
Year(s) built / renovated		1,996
Year(s) Acquired		2,003
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Weston Corporate Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Weston Corporate Center
Type		Office
Location		Weston, MA
Encumbrances		$ 0
Original Land		25,753
Original Building		92,312
Costs Capitalized Subsequent to Acquisition		(123)
Land and improvements		25,854
Buildings and Improvements		92,088
Land Held for Development		0
Development and Construction in Progress		0
Total		117,942
Accumulated Depreciation		$ 20,074
Year(s) built / renovated		2,010
Year(s) Acquired		2,001
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | One Freedom Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		One Freedom Square
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		9,929
Original Building		84,504
Costs Capitalized Subsequent to Acquisition		23,009
Land and improvements		9,883
Buildings and Improvements		107,559
Land Held for Development		0
Development and Construction in Progress		0
Total		117,442
Accumulated Depreciation		$ 44,381
Year(s) built / renovated		2,000
Year(s) Acquired		2,003
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Capital Gallery
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Capital Gallery
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		4,725
Original Building		29,565
Costs Capitalized Subsequent to Acquisition		78,897
Land and improvements		6,128
Buildings and Improvements		107,059
Land Held for Development		0
Development and Construction in Progress		0
Total		113,187
Accumulated Depreciation		$ 59,469
Year(s) built / renovated		1981/2006
Year(s) Acquired		2,007
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Two Freedom Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Two Freedom Square
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		13,930
Original Building		77,739
Costs Capitalized Subsequent to Acquisition		16,544
Land and improvements		13,866
Buildings and Improvements		94,347
Land Held for Development		0
Development and Construction in Progress		0
Total		108,213
Accumulated Depreciation		$ 43,283
Year(s) built / renovated		2,001
Year(s) Acquired		2,003
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | One and Two Reston Overlook
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		One and Two Reston Overlook
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		16,456
Original Building		66,192
Costs Capitalized Subsequent to Acquisition		20,216
Land and improvements		15,074
Buildings and Improvements		87,790
Land Held for Development		0
Development and Construction in Progress		0
Total		102,864
Accumulated Depreciation		$ 39,598
Year(s) built / renovated		1,999
Year(s) Acquired		2,000
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Discovery Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Discovery Square
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		11,198
Original Building		71,782
Costs Capitalized Subsequent to Acquisition		17,097
Land and improvements		11,146
Buildings and Improvements		88,931
Land Held for Development		0
Development and Construction in Progress		0
Total		100,077
Accumulated Depreciation		$ 38,454
Year(s) built / renovated		2,001
Year(s) Acquired		2,003
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 355 Main Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		355 Main Street
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		18,863
Original Building		53,346
Costs Capitalized Subsequent to Acquisition		27,360
Land and improvements		21,098
Buildings and Improvements		78,471
Land Held for Development		0
Development and Construction in Progress		0
Total		99,569
Accumulated Depreciation		$ 25,286
Year(s) built / renovated		1981/1996/2013
Year(s) Acquired		2,006
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 140 Kendrick Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		140 Kendrick Street
Type		Office
Location		Needham, MA
Encumbrances		$ 0
Original Land		18,095
Original Building		66,905
Costs Capitalized Subsequent to Acquisition		11,476
Land and improvements		18,095
Buildings and Improvements		78,381
Land Held for Development		0
Development and Construction in Progress		0
Total		96,476
Accumulated Depreciation		$ 25,315
Year(s) built / renovated		2,000
Year(s) Acquired		2,004
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 90 Broadway
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		90 Broadway
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		19,104
Original Building		52,078
Costs Capitalized Subsequent to Acquisition		16,869
Land and improvements		20,741
Buildings and Improvements		67,310
Land Held for Development		0
Development and Construction in Progress		0
Total		88,051
Accumulated Depreciation		$ 17,056
Year(s) built / renovated		1983/1998/2013
Year(s) Acquired		2,006
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 10 CityPoint
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		10 CityPoint
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		1,953
Original Building		85,752
Costs Capitalized Subsequent to Acquisition		0
Land and improvements		1,953
Buildings and Improvements		85,752
Land Held for Development		0
Development and Construction in Progress		0
Total		87,705
Accumulated Depreciation		$ 1,601
Year(s) built / renovated		2,016
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 230 CityPoint
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		230 CityPoint
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		13,189
Original Building		49,823
Costs Capitalized Subsequent to Acquisition		18,570
Land and improvements		13,189
Buildings and Improvements		68,393
Land Held for Development		0
Development and Construction in Progress		0
Total		81,582
Accumulated Depreciation		$ 23,106
Year(s) built / renovated		1,992
Year(s) Acquired		2,005
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 77 CityPoint
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		77 CityPoint
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		13,847
Original Building		60,383
Costs Capitalized Subsequent to Acquisition		5,598
Land and improvements		13,847
Buildings and Improvements		65,981
Land Held for Development		0
Development and Construction in Progress		0
Total		79,828
Accumulated Depreciation		$ 20,963
Year(s) built / renovated		2,008
Year(s) Acquired		2,001
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Waltham Weston Corporate Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Waltham Weston Corporate Center
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		10,385
Original Building		60,694
Costs Capitalized Subsequent to Acquisition		7,902
Land and improvements		10,350
Buildings and Improvements		68,631
Land Held for Development		0
Development and Construction in Progress		0
Total		78,981
Accumulated Depreciation		$ 26,690
Year(s) built / renovated		2,003
Year(s) Acquired		1,999
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 3625-3635 Peterson Way
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		3625-3635 Peterson Way
Type		Office
Location		Santa Clara, CA
Encumbrances		$ 0
Original Land		63,206
Original Building		14,879
Costs Capitalized Subsequent to Acquisition		31
Land and improvements		63,206
Buildings and Improvements		14,879
Land Held for Development		31
Development and Construction in Progress		0
Total		78,116
Accumulated Depreciation		$ 2,093
Year(s) built / renovated		1,979
Year(s) Acquired		2,016
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | North First Business Park
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		North First Business Park
Type		Office
Location		San Jose, CA
Encumbrances		$ 0
Original Land		58,402
Original Building		13,069
Costs Capitalized Subsequent to Acquisition		3,909
Land and improvements		23,371
Buildings and Improvements		16,099
Land Held for Development		35,910
Development and Construction in Progress		0
Total		75,380
Accumulated Depreciation		$ 15,811
Year(s) built / renovated		1,981
Year(s) Acquired		2,007
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 2440 West El Camino Real
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		2440 West El Camino Real
Type		Office
Location		Mountain View, CA
Encumbrances		$ 0
Original Land		16,741
Original Building		51,285
Costs Capitalized Subsequent to Acquisition		1,814
Land and improvements		16,741
Buildings and Improvements		53,099
Land Held for Development		0
Development and Construction in Progress		0
Total		69,840
Accumulated Depreciation		$ 9,817
Year(s) built / renovated		1987/2003
Year(s) Acquired		2,011
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 300 Binney Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		300 Binney Street
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		18,080
Original Building		51,262
Costs Capitalized Subsequent to Acquisition		140
Land and improvements		18,080
Buildings and Improvements		51,402
Land Held for Development		0
Development and Construction in Progress		0
Total		69,482
Accumulated Depreciation		$ 6,059
Year(s) built / renovated		2,013
Year(s) Acquired		2,009
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Reston Corporate Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Reston Corporate Center
Type		Office
Location		Reston, VA
Encumbrances		$ 0
Original Land		9,135
Original Building		50,857
Costs Capitalized Subsequent to Acquisition		3,645
Land and improvements		9,496
Buildings and Improvements		54,141
Land Held for Development		0
Development and Construction in Progress		0
Total		63,637
Accumulated Depreciation		$ 24,703
Year(s) built / renovated		1,984
Year(s) Acquired		1,998
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Wisconsin Place
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Wisconsin Place
Type		Office
Location		Chevy Chase, MD
Encumbrances		$ 0
Original Land		0
Original Building		53,349
Costs Capitalized Subsequent to Acquisition		9,884
Land and improvements		0
Buildings and Improvements		63,233
Land Held for Development		0
Development and Construction in Progress		0
Total		63,233
Accumulated Depreciation		$ 16,406
Year(s) built / renovated		2,009
Year(s) Acquired		2,004
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | New Dominion Technology Park, Bldg. Two
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		New Dominion Technology Park, Bldg. Two
Type		Office
Location		Herndon, VA
Encumbrances		$ 0
Original Land		5,584
Original Building		51,868
Costs Capitalized Subsequent to Acquisition		349
Land and improvements		5,574
Buildings and Improvements		52,227
Land Held for Development		0
Development and Construction in Progress		0
Total		57,801
Accumulated Depreciation		$ 21,128
Year(s) built / renovated		2,004
Year(s) Acquired		1,998
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 200 West Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		200 West Street
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		16,148
Original Building		24,983
Costs Capitalized Subsequent to Acquisition		7,441
Land and improvements		16,148
Buildings and Improvements		32,424
Land Held for Development		0
Development and Construction in Progress		0
Total		48,572
Accumulated Depreciation		$ 18,983
Year(s) built / renovated		1,999
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | New Dominion Technology Park, Bldg. One
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		New Dominion Technology Park, Bldg. One
Type		Office
Location		Herndon, VA
Encumbrances		$ 35,485
Original Land		3,880
Original Building		43,227
Costs Capitalized Subsequent to Acquisition		1,073
Land and improvements		3,880
Buildings and Improvements		44,300
Land Held for Development		0
Development and Construction in Progress		0
Total		48,180
Accumulated Depreciation		$ 23,779
Year(s) built / renovated		2,001
Year(s) Acquired		1,998
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Sumner Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Sumner Square
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		624
Original Building		28,745
Costs Capitalized Subsequent to Acquisition		17,348
Land and improvements		958
Buildings and Improvements		45,759
Land Held for Development		0
Development and Construction in Progress		0
Total		46,717
Accumulated Depreciation		$ 21,809
Year(s) built / renovated		1,985
Year(s) Acquired		1,999
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | University Place
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		University Place
Type		Office
Location		Cambridge, MA
Encumbrances		$ 9,119
Original Land		0
Original Building		37,091
Costs Capitalized Subsequent to Acquisition		8,051
Land and improvements		27
Buildings and Improvements		45,115
Land Held for Development		0
Development and Construction in Progress		0
Total		45,142
Accumulated Depreciation		$ 24,910
Year(s) built / renovated		1,985
Year(s) Acquired		1,998
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 2600 Tower Oaks Boulevard
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		2600 Tower Oaks Boulevard
Type		Office
Location		Rockville, MD
Encumbrances		$ 0
Original Land		4,243
Original Building		31,125
Costs Capitalized Subsequent to Acquisition		6,918
Land and improvements		4,244
Buildings and Improvements		38,042
Land Held for Development		0
Development and Construction in Progress		0
Total		42,286
Accumulated Depreciation		$ 19,351
Year(s) built / renovated		2,001
Year(s) Acquired		1,998
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 255 Main Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		255 Main Street
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		134
Original Building		25,110
Costs Capitalized Subsequent to Acquisition		15,431
Land and improvements		134
Buildings and Improvements		40,541
Land Held for Development		0
Development and Construction in Progress		0
Total		40,675
Accumulated Depreciation		$ 27,158
Year(s) built / renovated		1,987
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Quorum Office Park
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Quorum Office Park
Type		Office
Location		Chelmsford, MA
Encumbrances		$ 0
Original Land		3,750
Original Building		32,454
Costs Capitalized Subsequent to Acquisition		4,115
Land and improvements		4,762
Buildings and Improvements		35,557
Land Held for Development		0
Development and Construction in Progress		0
Total		40,319
Accumulated Depreciation		$ 15,282
Year(s) built / renovated		2,001
Year(s) Acquired		2,000
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 150 Broadway
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		150 Broadway
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		850
Original Building		25,042
Costs Capitalized Subsequent to Acquisition		6,618
Land and improvements		822
Buildings and Improvements		31,688
Land Held for Development		0
Development and Construction in Progress		0
Total		32,510
Accumulated Depreciation		$ 15,127
Year(s) built / renovated		1,999
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 500 E Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		500 E Street
Type		Office
Location		Washington, DC
Encumbrances		$ 0
Original Land		109
Original Building		22,420
Costs Capitalized Subsequent to Acquisition		9,979
Land and improvements		1,569
Buildings and Improvements		30,939
Land Held for Development		0
Development and Construction in Progress		0
Total		32,508
Accumulated Depreciation		$ 22,318
Year(s) built / renovated		1,987
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 325 Main Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		325 Main Street
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		174
Original Building		12,200
Costs Capitalized Subsequent to Acquisition		11,485
Land and improvements		772
Buildings and Improvements		23,087
Land Held for Development		0
Development and Construction in Progress		0
Total		23,859
Accumulated Depreciation		$ 12,104
Year(s) built / renovated		1987/2013
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 105 Broadway
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		105 Broadway
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		1,299
Original Building		12,943
Costs Capitalized Subsequent to Acquisition		5,092
Land and improvements		1,868
Buildings and Improvements		17,466
Land Held for Development		0
Development and Construction in Progress		0
Total		19,334
Accumulated Depreciation		$ 12,580
Year(s) built / renovated		1,990
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Lexington Office Park
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Lexington Office Park
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		998
Original Building		1,426
Costs Capitalized Subsequent to Acquisition		16,717
Land and improvements		1,073
Buildings and Improvements		18,068
Land Held for Development		0
Development and Construction in Progress		0
Total		19,141
Accumulated Depreciation		$ 12,335
Year(s) built / renovated		1,982
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 40 Shattuck Road
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		40 Shattuck Road
Type		Office
Location		Andover, MA
Encumbrances		$ 0
Original Land		709
Original Building		14,740
Costs Capitalized Subsequent to Acquisition		2,632
Land and improvements		709
Buildings and Improvements		17,372
Land Held for Development		0
Development and Construction in Progress		0
Total		18,081
Accumulated Depreciation		$ 7,352
Year(s) built / renovated		2,001
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 201 Spring Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		201 Spring Street
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		2,849
Original Building		15,303
Costs Capitalized Subsequent to Acquisition		(1,085)
Land and improvements		2,849
Buildings and Improvements		14,218
Land Held for Development		0
Development and Construction in Progress		0
Total		17,067
Accumulated Depreciation		$ 7,233
Year(s) built / renovated		1,997
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | The Point
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		The Point
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		6,395
Original Building		10,040
Costs Capitalized Subsequent to Acquisition		408
Land and improvements		6,480
Buildings and Improvements		10,363
Land Held for Development		0
Development and Construction in Progress		0
Total		16,843
Accumulated Depreciation		$ 397
Year(s) built / renovated		2,015
Year(s) Acquired		2,007
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 690 Folsom Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		690 Folsom Street
Type		Office
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		3,219
Original Building		11,038
Costs Capitalized Subsequent to Acquisition		1,157
Land and improvements		3,219
Buildings and Improvements		12,195
Land Held for Development		0
Development and Construction in Progress		0
Total		15,414
Accumulated Depreciation		$ 801
Year(s) built / renovated		2,015
Year(s) Acquired		2,012
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 91 Hartwell Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		91 Hartwell Avenue
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		784
Original Building		6,464
Costs Capitalized Subsequent to Acquisition		7,627
Land and improvements		784
Buildings and Improvements		14,091
Land Held for Development		0
Development and Construction in Progress		0
Total		14,875
Accumulated Depreciation		$ 8,930
Year(s) built / renovated		1,985
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 92-100 Hayden Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		92-100 Hayden Avenue
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		594
Original Building		6,748
Costs Capitalized Subsequent to Acquisition		7,452
Land and improvements		619
Buildings and Improvements		14,175
Land Held for Development		0
Development and Construction in Progress		0
Total		14,794
Accumulated Depreciation		$ 11,910
Year(s) built / renovated		1,985
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 181 Spring Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		181 Spring Street
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		1,066
Original Building		9,520
Costs Capitalized Subsequent to Acquisition		1,818
Land and improvements		1,066
Buildings and Improvements		11,338
Land Held for Development		0
Development and Construction in Progress		0
Total		12,404
Accumulated Depreciation		$ 4,798
Year(s) built / renovated		1,999
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 145 Broadway
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		145 Broadway
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		121
Original Building		5,535
Costs Capitalized Subsequent to Acquisition		6,360
Land and improvements		121
Buildings and Improvements		10,027
Land Held for Development		0
Development and Construction in Progress		1,868
Total		12,016
Accumulated Depreciation		$ 8,385
Year(s) built / renovated		1,984
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 33 Hayden Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		33 Hayden Avenue
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		266
Original Building		3,234
Costs Capitalized Subsequent to Acquisition		8,150
Land and improvements		266
Buildings and Improvements		11,384
Land Held for Development		0
Development and Construction in Progress		0
Total		11,650
Accumulated Depreciation		$ 7,480
Year(s) built / renovated		1,979
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 195 West Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		195 West Street
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		1,611
Original Building		6,652
Costs Capitalized Subsequent to Acquisition		3,351
Land and improvements		1,611
Buildings and Improvements		10,003
Land Held for Development		0
Development and Construction in Progress		0
Total		11,614
Accumulated Depreciation		$ 7,309
Year(s) built / renovated		1,990
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 7501 Boston Boulevard, Building Seven
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7501 Boston Boulevard, Building Seven
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		665
Original Building		9,273
Costs Capitalized Subsequent to Acquisition		30
Land and improvements		665
Buildings and Improvements		9,303
Land Held for Development		0
Development and Construction in Progress		0
Total		9,968
Accumulated Depreciation		$ 4,490
Year(s) built / renovated		1,997
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 7435 Boston Boulevard, Building One
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7435 Boston Boulevard, Building One
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		392
Original Building		3,822
Costs Capitalized Subsequent to Acquisition		4,423
Land and improvements		486
Buildings and Improvements		8,151
Land Held for Development		0
Development and Construction in Progress		0
Total		8,637
Accumulated Depreciation		$ 6,213
Year(s) built / renovated		1,982
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 250 Binney Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		250 Binney Street
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		110
Original Building		4,483
Costs Capitalized Subsequent to Acquisition		2,939
Land and improvements		110
Buildings and Improvements		7,422
Land Held for Development		0
Development and Construction in Progress		0
Total		7,532
Accumulated Depreciation		$ 4,552
Year(s) built / renovated		1,983
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 7450 Boston Boulevard, Building Three
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7450 Boston Boulevard, Building Three
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		1,165
Original Building		4,681
Costs Capitalized Subsequent to Acquisition		1,393
Land and improvements		1,327
Buildings and Improvements		5,912
Land Held for Development		0
Development and Construction in Progress		0
Total		7,239
Accumulated Depreciation		$ 3,232
Year(s) built / renovated		1,987
Year(s) Acquired		1,998
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 453 Ravendale Drive
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		453 Ravendale Drive
Type		Office
Location		Mountain View, CA
Encumbrances		$ 0
Original Land		5,477
Original Building		1,090
Costs Capitalized Subsequent to Acquisition		408
Land and improvements		5,477
Buildings and Improvements		1,498
Land Held for Development		0
Development and Construction in Progress		0
Total		6,975
Accumulated Depreciation		$ 338
Year(s) built / renovated		1,977
Year(s) Acquired		2,012
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 8000 Grainger Court, Building Five
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		8000 Grainger Court, Building Five
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		366
Original Building		4,282
Costs Capitalized Subsequent to Acquisition		2,013
Land and improvements		453
Buildings and Improvements		6,208
Land Held for Development		0
Development and Construction in Progress		0
Total		6,661
Accumulated Depreciation		$ 5,294
Year(s) built / renovated		1,984
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 17 Hartwell Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		17 Hartwell Avenue
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		26
Original Building		150
Costs Capitalized Subsequent to Acquisition		5,952
Land and improvements		26
Buildings and Improvements		6,102
Land Held for Development		0
Development and Construction in Progress		0
Total		6,128
Accumulated Depreciation		$ 519
Year(s) built / renovated		1,968
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 7300 Boston Boulevard, Building Thirteen
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7300 Boston Boulevard, Building Thirteen
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		608
Original Building		4,773
Costs Capitalized Subsequent to Acquisition		497
Land and improvements		608
Buildings and Improvements		5,270
Land Held for Development		0
Development and Construction in Progress		0
Total		5,878
Accumulated Depreciation		$ 4,968
Year(s) built / renovated		2,002
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 7500 Boston Boulevard, Building Six
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7500 Boston Boulevard, Building Six
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		138
Original Building		3,749
Costs Capitalized Subsequent to Acquisition		1,954
Land and improvements		273
Buildings and Improvements		5,568
Land Held for Development		0
Development and Construction in Progress		0
Total		5,841
Accumulated Depreciation		$ 4,428
Year(s) built / renovated		1,985
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 7601 Boston Boulevard, Building Eight
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7601 Boston Boulevard, Building Eight
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		200
Original Building		878
Costs Capitalized Subsequent to Acquisition		4,354
Land and improvements		378
Buildings and Improvements		5,054
Land Held for Development		0
Development and Construction in Progress		0
Total		5,432
Accumulated Depreciation		$ 3,900
Year(s) built / renovated		1,986
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 8000 Corporate Court, Building Eleven
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		8000 Corporate Court, Building Eleven
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		136
Original Building		3,071
Costs Capitalized Subsequent to Acquisition		1,264
Land and improvements		687
Buildings and Improvements		3,784
Land Held for Development		0
Development and Construction in Progress		0
Total		4,471
Accumulated Depreciation		$ 2,708
Year(s) built / renovated		1,989
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 7375 Boston Boulevard, Building Ten
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7375 Boston Boulevard, Building Ten
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		23
Original Building		2,685
Costs Capitalized Subsequent to Acquisition		731
Land and improvements		47
Buildings and Improvements		3,392
Land Held for Development		0
Development and Construction in Progress		0
Total		3,439
Accumulated Depreciation		$ 2,437
Year(s) built / renovated		1,988
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 7374 Boston Boulevard, Building Four
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7374 Boston Boulevard, Building Four
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		241
Original Building		1,605
Costs Capitalized Subsequent to Acquisition		1,355
Land and improvements		303
Buildings and Improvements		2,898
Land Held for Development		0
Development and Construction in Progress		0
Total		3,201
Accumulated Depreciation		$ 2,375
Year(s) built / renovated		1,984
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 7451 Boston Boulevard, Building Two
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		7451 Boston Boulevard, Building Two
Type		Office
Location		Springfield, VA
Encumbrances		$ 0
Original Land		249
Original Building		1,542
Costs Capitalized Subsequent to Acquisition		1,346
Land and improvements		535
Buildings and Improvements		2,602
Land Held for Development		0
Development and Construction in Progress		0
Total		3,137
Accumulated Depreciation		$ 2,264
Year(s) built / renovated		1,982
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 32 Hartwell Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		32 Hartwell Avenue
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		168
Original Building		1,943
Costs Capitalized Subsequent to Acquisition		426
Land and improvements		168
Buildings and Improvements		2,369
Land Held for Development		0
Development and Construction in Progress		0
Total		2,537
Accumulated Depreciation		$ 1,782
Year(s) built / renovated		1968/1979/1987
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | 164 Lexington Road
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		164 Lexington Road
Type		Office
Location		Billerica, MA
Encumbrances		$ 0
Original Land		592
Original Building		1,370
Costs Capitalized Subsequent to Acquisition		117
Land and improvements		592
Buildings and Improvements		1,487
Land Held for Development		0
Development and Construction in Progress		0
Total		2,079
Accumulated Depreciation		$ 782
Year(s) built / renovated		1,982
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | The Avant at Reston Town Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		The Avant at Reston Town Center
Type		Residential
Location		Reston, VA
Encumbrances		$ 0
Original Land		20,350
Original Building		91,995
Costs Capitalized Subsequent to Acquisition		815
Land and improvements		20,350
Buildings and Improvements		92,810
Land Held for Development		0
Development and Construction in Progress		0
Total		113,160
Accumulated Depreciation		$ 7,306
Year(s) built / renovated		2,014
Year(s) Acquired		2,010
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | The Lofts at Atlantic Wharf
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		The Lofts at Atlantic Wharf
Type		Residential
Location		Boston, MA
Encumbrances		$ 0
Original Land		3,529
Original Building		54,891
Costs Capitalized Subsequent to Acquisition		1,663
Land and improvements		3,529
Buildings and Improvements		56,554
Land Held for Development		0
Development and Construction in Progress		0
Total		60,083
Accumulated Depreciation		$ 8,105
Year(s) built / renovated		2,011
Year(s) Acquired		2,007
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Boston Marriott Cambridge
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Boston Marriott Cambridge
Type		Hotel
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		478
Original Building		37,918
Costs Capitalized Subsequent to Acquisition		34,176
Land and improvements		478
Buildings and Improvements		72,094
Land Held for Development		0
Development and Construction in Progress		0
Total		72,572
Accumulated Depreciation		$ 50,357
Year(s) built / renovated		1,986
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Kendall Center Green Garage
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Green Garage
Type		Garage
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		0
Original Building		35,035
Costs Capitalized Subsequent to Acquisition		6,977
Land and improvements		0
Buildings and Improvements		42,012
Land Held for Development		0
Development and Construction in Progress		0
Total		42,012
Accumulated Depreciation		$ 9,250
Year(s) built / renovated		1,984
Year(s) Acquired		2,006
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Kendall Center Yellow Garage
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Yellow Garage
Type		Garage
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		1,256
Original Building		15,697
Costs Capitalized Subsequent to Acquisition		859
Land and improvements		1,256
Buildings and Improvements		16,556
Land Held for Development		0
Development and Construction in Progress		0
Total		17,812
Accumulated Depreciation		$ 4,580
Year(s) built / renovated		2,006
Year(s) Acquired		2,004
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Kendall Center Blue Garage
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Blue Garage
Type		Garage
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		1,163
Original Building		11,633
Costs Capitalized Subsequent to Acquisition		1,105
Land and improvements		1,163
Buildings and Improvements		12,738
Land Held for Development		0
Development and Construction in Progress		0
Total		13,901
Accumulated Depreciation		$ 8,982
Year(s) built / renovated		1,990
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Salesforce Tower
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Salesforce Tower
Type		Development
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		723,866
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		0
Development and Construction in Progress		723,866
Total		723,866
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,013
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | Signature at Reston (formerly Reston Signature Site)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Signature at Reston (formerly Reston Signature Site)
Type		Development
Location		Reston, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		96,444
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		0
Development and Construction in Progress		96,444
Total		96,444
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,013
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | 191 Spring Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		191 Spring Street
Type		Development
Location		Lexington, MA
Encumbrances		$ 0
Original Land		2,850
Original Building		27,166
Costs Capitalized Subsequent to Acquisition		1,935
Land and improvements		2,850
Buildings and Improvements		27,678
Land Held for Development		0
Development and Construction in Progress		1,423
Total		31,951
Accumulated Depreciation		$ 21,001
Year(s) built / renovated		1971/1995
Year(s) Acquired		1,997
Depreciable Lives (Years)	[6]	(1)
Boston Properties Limited Partnership | Proto at Cambridge (formerly Cambridge Residential / 88 Ames)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Proto at Cambridge (formerly Cambridge Residential / 88 Ames)
Type		Development
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		24,334
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		0
Development and Construction in Progress		24,334
Total		24,334
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,015
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | Springfield Metro Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Springfield Metro Center
Type		Land
Location		Springfield, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		35,430
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		35,430
Development and Construction in Progress		0
Total		35,430
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,007
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | Tower Oaks Master Plan
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Tower Oaks Master Plan
Type		Land
Location		Rockville, MD
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		29,209
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		29,209
Development and Construction in Progress		0
Total		29,209
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		1,998
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | Plaza at Almaden
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Plaza at Almaden
Type		Land
Location		San Jose, CA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		29,081
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		29,081
Development and Construction in Progress		0
Total		29,081
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,006
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | 6601 & 6605 Springfield Center Drive
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		6601 & 6605 Springfield Center Drive
Type		Land
Location		Springfield, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		13,866
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		13,866
Development and Construction in Progress		0
Total		13,866
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,007
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | 214 Third Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		214 Third Avenue
Type		Land
Location		Waltham, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		13,795
Land and improvements		0
Buildings and Improvements		146
Land Held for Development		13,649
Development and Construction in Progress		0
Total		13,795
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,006
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | 103 Fourth Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		103 Fourth Avenue
Type		Land
Location		Waltham, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		12,052
Land and improvements		0
Buildings and Improvements		49
Land Held for Development		12,003
Development and Construction in Progress		0
Total		12,052
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,007
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | 20 CityPoint
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		20 CityPoint
Type		Land
Location		Waltham, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		11,666
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		11,666
Development and Construction in Progress		0
Total		11,666
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,007
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | Reston Gateway
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Reston Gateway
Type		Land
Location		Reston, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		10,841
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		10,841
Development and Construction in Progress		0
Total		10,841
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		1,998
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | Reston Eastgate
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Reston Eastgate
Type		Land
Location		Reston, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		9,906
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		9,906
Development and Construction in Progress		0
Total		9,906
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,001
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | Crane Meadow
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Crane Meadow
Type		Land
Location		Marlborough, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		8,754
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		8,754
Development and Construction in Progress		0
Total		8,754
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,000
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | Washingtonian North
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Washingtonian North
Type		Land
Location		Gaithersburg, MD
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		7,697
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		7,697
Development and Construction in Progress		0
Total		7,697
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		1,998
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | Kendall Center Master Plan
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Master Plan
Type		Land
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		4,062
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		4,062
Development and Construction in Progress		0
Total		4,062
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | Fourth and Harrison
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Fourth and Harrison
Type		Land
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		3,936
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		3,936
Development and Construction in Progress		0
Total		3,936
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | North First Master Plan
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		North First Master Plan
Type		Land
Location		San Jose, CA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		3,014
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		3,014
Development and Construction in Progress		0
Total		3,014
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		2,007
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | Broad Run Business Park
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Broad Run Business Park
Type		Land
Location		Loudoun County, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		2,694
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		2,694
Development and Construction in Progress		0
Total		2,694
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		1,998
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | MacArthur Station
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		MacArthur Station
Type		Land
Location		Oakland, CA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		1,316
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		1,316
Development and Construction in Progress		0
Total		1,316
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | 30 Shattuck Road
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		30 Shattuck Road
Type		Land
Location		Andover, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		1,214
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		1,214
Development and Construction in Progress		0
Total		1,214
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		1,997
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership | 2100 Pennsylvania Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		2100 Pennsylvania Avenue
Type		Land
Location		Washington, DC
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		286
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		286
Development and Construction in Progress		0
Total		286
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Year(s) Acquired		N/A
Depreciable Lives (Years)		N/A
Minimum [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Life Used for Depreciation		life of the lease
Minimum [Member] | Boston Properties Limited Partnership
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Life Used for Depreciation		life of the lease
[1]	Includes the unamortized balance of the historical fair value adjustment and unamortized deferred financing costs totaling approximately $33.8 million and $(2.4) million, respectively.
[2]	Includes pre-development costs.
[3]	Depreciation of the buildings and improvements are calculated over lives ranging from the life of the lease to 40 years.
[4]	Includes the unamortized balance of the historical fair value adjustment and unamortized deferred financing costs totaling approximately $33.8 million and $(2.4) million, respectively.
[5]	Includes pre-development costs.
[6]	Depreciation of the buildings and improvements are calculated over lives ranging from the life of the lease to 40 years.

Real Estate and Accumulated 106

Real Estate and Accumulated Depreciation Activity of Real Estate and Accumulated Depreciation (BPLP) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Real Estate, Balance at the beginning of the year	$ 19,451,683	$ 19,208,417	$ 18,953,601
Real Estate, Additions to / improvements of real estate	977,287	700,792	594,296
Real Estate, Assets sold / written off	(314,394)	(457,526)	(339,480)
Real Estate, Balance at the end of the year	20,114,576	19,451,683	19,208,417
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Accumulated depreciation, Balance at beginning of the year	3,905,940	3,529,978	3,145,701
Accumulated depreciation, Depreciation expense	560,024	486,450	456,176
Accumulated depreciation, Assets sold / written off	(264,073)	(110,488)	(71,899)
Accumulated depreciation, Balance at end of the year	4,201,891	3,905,940	3,529,978
Boston Properties Limited Partnership
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]
Real Estate, Balance at the beginning of the year	19,031,289	18,786,572	18,523,277
Real Estate, Additions to / improvements of real estate	977,287	700,792	594,296
Real Estate, Assets sold / written off	(307,391)	(456,075)	(331,001)
Real Estate, Balance at the end of the year	19,701,185	19,031,289	18,786,572
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Accumulated depreciation, Balance at beginning of the year	3,826,862	3,458,640	3,081,040
Accumulated depreciation, Depreciation expense	548,397	478,457	447,667
Accumulated depreciation, Assets sold / written off	(259,239)	(110,235)	(70,067)
Accumulated depreciation, Balance at end of the year	$ 4,116,020	$ 3,826,862	$ 3,458,640