Real Estate and Accumulated Depreciation Schedule of Real Estate and Accumulated Depreciation (BPLP) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	[1]	$ 3,438,714
Original Land		4,602,809
Original Building		11,248,289
Costs Capitalized Subsequent to Acquisition		3,600,585
Land and improvements		4,806,021
Buildings and Improvements		13,629,532
Land Held for Development		252,195
Development and Construction in Progress		763,935
Total		19,451,683
Accumulated Depreciation		3,905,940
Furniture, fixtures and equipment		29,852	$ 27,986
Furniture, fixtures and equipment accumulated depreciation		19,954
Real Estate Aggregate Cost For Tax Purposes		15,000,000
Real Estate Aggregate Accumulated Depreciation For Tax Purposes		$ 3,000,000
Real Estate and Accumulated Depreciation, Life Used for Depreciation		40 years
Unamortized balance of historical fair value adjustments		$ 80,235
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		$ 1,377,986
Original Land		1,796,252
Original Building		1,532,654
Costs Capitalized Subsequent to Acquisition		45,800
Land and improvements		1,796,252
Buildings and Improvements		1,578,454
Land Held for Development		0
Development and Construction in Progress		0
Total		3,374,706
Accumulated Depreciation		$ 128,488
Year(s) built / renovated		1968
Depreciable Lives (Years)	[2]	-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		526,740
Land and improvements		107,426
Buildings and Improvements		1,082,583
Land Held for Development		1,714
Development and Construction in Progress		161,688
Total		1,353,411
Accumulated Depreciation		$ 446,792
Year(s) built / renovated		1965/1993/2002
Depreciable Lives (Years)	[2]	-1
Embarcadero Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Embarcadero Center
Type		Office
Location		San Francisco, CA
Encumbrances		$ 348,886
Original Land		179,697
Original Building		847,410
Costs Capitalized Subsequent to Acquisition		332,276
Land and improvements		195,987
Buildings and Improvements		1,163,396
Land Held for Development		0
Development and Construction in Progress		0
Total		1,359,383
Accumulated Depreciation		$ 542,103
Year(s) built / renovated		1970/1989
Depreciable Lives (Years)	[2]	-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		110,972
Land and improvements		354,107
Buildings and Improvements		796,423
Land Held for Development		0
Development and Construction in Progress		0
Total		1,150,530
Accumulated Depreciation		$ 265,266
Year(s) built / renovated		1961
Depreciable Lives (Years)	[2]	-1
200 Clarendon Street and Garage (formerly The John Hancock Tower and Garage)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		200 Clarendon Street and Garage (formerly the John Hancock Tower and Garage)
Type		Office
Location		Boston, MA
Encumbrances		$ 0
Original Land		219,543
Original Building		667,884
Costs Capitalized Subsequent to Acquisition		112,229
Land and improvements		219,616
Buildings and Improvements		776,755
Land Held for Development		3,285
Development and Construction in Progress		0
Total		999,656
Accumulated Depreciation		$ 128,815
Year(s) built / renovated		1976
Depreciable Lives (Years)	[2]	-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		$ 699,061
Original Land		241,600
Original Building		494,782
Costs Capitalized Subsequent to Acquisition		231,812
Land and improvements		289,639
Buildings and Improvements		677,238
Land Held for Development		1,317
Development and Construction in Progress		0
Total		968,194
Accumulated Depreciation		$ 250,128
Year(s) built / renovated		1977/1997
Depreciable Lives (Years)	[2]	-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		16,488
Land and improvements		285,263
Buildings and Improvements		619,655
Land Held for Development		0
Development and Construction in Progress		0
Total		904,918
Accumulated Depreciation		$ 28,349
Year(s) built / renovated		2014
Depreciable Lives (Years)	[2]	-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		128,069
Land and improvements		103,064
Buildings and Improvements		464,086
Land Held for Development		2,475
Development and Construction in Progress		40,810
Total		610,435
Accumulated Depreciation		$ 198,387
Year(s) built / renovated		1983-1999
Depreciable Lives (Years)	[2]	-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		84,722
Land and improvements		169,193
Buildings and Improvements		461,380
Land Held for Development		0
Development and Construction in Progress		0
Total		630,573
Accumulated Depreciation		$ 164,767
Year(s) built / renovated		2004
Depreciable Lives (Years)	[2]	-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		15,555
Land and improvements		131,067
Buildings and Improvements		450,933
Land Held for Development		576
Development and Construction in Progress		0
Total		582,576
Accumulated Depreciation		$ 60,125
Year(s) built / renovated		1971-1975
Depreciable Lives (Years)	[2]	-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		16,376
Land and improvements		63,988
Buildings and Improvements		470,913
Land Held for Development		0
Development and Construction in Progress		0
Total		534,901
Accumulated Depreciation		$ 70,552
Year(s) built / renovated		2011
Depreciable Lives (Years)	[2]	-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		19,575
Land and improvements		103,000
Buildings and Improvements		273,240
Land Held for Development		0
Development and Construction in Progress		0
Total		376,240
Accumulated Depreciation		$ 34,640
Year(s) built / renovated		2012
Depreciable Lives (Years)	[2]	-1
Fountain Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Fountain Square
Type		Office
Location		Reston, VA
Encumbrances		$ 213,499
Original Land		56,853
Original Building		306,298
Costs Capitalized Subsequent to Acquisition		12,459
Land and improvements		56,853
Buildings and Improvements		318,757
Land Held for Development		0
Development and Construction in Progress		0
Total		375,610
Accumulated Depreciation		$ 39,508
Year(s) built / renovated		1986-1990
Depreciable Lives (Years)	[2]	-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		$ 750,000
Original Land		81,040
Original Building		100,507
Costs Capitalized Subsequent to Acquisition		149,551
Land and improvements		87,852
Buildings and Improvements		243,246
Land Held for Development		0
Development and Construction in Progress		0
Total		331,098
Accumulated Depreciation		$ 160,354
Year(s) built / renovated		1986
Depreciable Lives (Years)	[2]	-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		7,348
Land and improvements		72,545
Buildings and Improvements		227,114
Land Held for Development		0
Development and Construction in Progress		0
Total		299,659
Accumulated Depreciation		$ 13,091
Year(s) built / renovated		2014
Depreciable Lives (Years)	[2]	-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		11,977
Land and improvements		13,687
Buildings and Improvements		249,372
Land Held for Development		0
Development and Construction in Progress		0
Total		263,059
Accumulated Depreciation		$ 70,437
Year(s) built / renovated		2008-2009
Depreciable Lives (Years)	[2]	-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		65,997
Land and improvements		18,789
Buildings and Improvements		214,448
Land Held for Development		0
Development and Construction in Progress		0
Total		233,237
Accumulated Depreciation		$ 40,812
Year(s) built / renovated		1985-1989
Depreciable Lives (Years)	[2]	-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		54,027
Land and improvements		30,627
Buildings and Improvements		190,900
Land Held for Development		0
Development and Construction in Progress		0
Total		221,527
Accumulated Depreciation		$ 94,083
Year(s) built / renovated		1984/1986/2002
Depreciable Lives (Years)	[2]	-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		0
Land and improvements		40,933
Buildings and Improvements		148,378
Land Held for Development		0
Development and Construction in Progress		0
Total		189,311
Accumulated Depreciation		$ 3,221
Year(s) built / renovated		2015
Depreciable Lives (Years)	[2]	-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		5,230
Land and improvements		0
Buildings and Improvements		188,771
Land Held for Development		0
Development and Construction in Progress		0
Total		188,771
Accumulated Depreciation		$ 33,039
Year(s) built / renovated		2011
Depreciable Lives (Years)	[2]	-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		5,581
Land and improvements		95,066
Buildings and Improvements		73,954
Land Held for Development		0
Development and Construction in Progress		0
Total		169,020
Accumulated Depreciation		$ 9,581
Year(s) built / renovated		1977-1981/2007-2013
Depreciable Lives (Years)	[2]	-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		46,547
Land and improvements		20,118
Buildings and Improvements		128,975
Land Held for Development		0
Development and Construction in Progress		8,678
Total		157,771
Accumulated Depreciation		$ 57,706
Year(s) built / renovated		1955/1987
Depreciable Lives (Years)	[2]	-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		1,276
Land and improvements		18,062
Buildings and Improvements		110,273
Land Held for Development		0
Development and Construction in Progress		0
Total		128,335
Accumulated Depreciation		$ 33,374
Year(s) built / renovated		2003-2006
Depreciable Lives (Years)	[2]	-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		10,841
Land and improvements		35,382
Buildings and Improvements		95,151
Land Held for Development		0
Development and Construction in Progress		0
Total		130,533
Accumulated Depreciation		$ 35,457
Year(s) built / renovated		1996
Depreciable Lives (Years)	[2]	-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		19,098
Land and improvements		27,135
Buildings and Improvements		100,256
Land Held for Development		0
Development and Construction in Progress		0
Total		127,391
Accumulated Depreciation		$ 45,063
Year(s) built / renovated		1984
Depreciable Lives (Years)	[2]	-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		$ 17,023
Year(s) built / renovated		2010
Depreciable Lives (Years)	[2]	-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		88,569
Land and improvements		8,662
Buildings and Improvements		114,197
Land Held for Development		0
Development and Construction in Progress		0
Total		122,859
Accumulated Depreciation		$ 57,489
Year(s) built / renovated		1981/2006
Depreciable Lives (Years)	[2]	-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		19,613
Land and improvements		11,293
Buildings and Improvements		102,753
Land Held for Development		0
Development and Construction in Progress		0
Total		114,046
Accumulated Depreciation		$ 41,106
Year(s) built / renovated		2000
Depreciable Lives (Years)	[2]	-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		21,374
Land and improvements		15,420
Buildings and Improvements		97,623
Land Held for Development		0
Development and Construction in Progress		0
Total		113,043
Accumulated Depreciation		$ 41,164
Year(s) built / renovated		2001
Depreciable Lives (Years)	[2]	-1
415 Main Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		415 Main Street
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		3,457
Original Building		97,136
Costs Capitalized Subsequent to Acquisition		2,986
Land and improvements		4,125
Buildings and Improvements		99,454
Land Held for Development		0
Development and Construction in Progress		0
Total		103,579
Accumulated Depreciation		$ 59,405
Year(s) built / renovated		2006
Depreciable Lives (Years)	[2]	-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		28,822
Land and improvements		21,173
Buildings and Improvements		79,858
Land Held for Development		0
Development and Construction in Progress		0
Total		101,031
Accumulated Depreciation		$ 23,372
Year(s) built / renovated		1981/1996/2013
Depreciable Lives (Years)	[2]	-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		22,385
Land and improvements		16,179
Buildings and Improvements		88,854
Land Held for Development		0
Development and Construction in Progress		0
Total		105,033
Accumulated Depreciation		$ 37,165
Year(s) built / renovated		1999
Depreciable Lives (Years)	[2]	-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		21,234
Land and improvements		12,533
Buildings and Improvements		91,681
Land Held for Development		0
Development and Construction in Progress		0
Total		104,214
Accumulated Depreciation		$ 35,835
Year(s) built / renovated		2001
Depreciable Lives (Years)	[2]	-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		15,075
Land and improvements		19,092
Buildings and Improvements		80,983
Land Held for Development		0
Development and Construction in Progress		0
Total		100,075
Accumulated Depreciation		$ 23,191
Year(s) built / renovated		2000
Depreciable Lives (Years)	[2]	-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		17,386
Land and improvements		20,785
Buildings and Improvements		67,783
Land Held for Development		0
Development and Construction in Progress		0
Total		88,568
Accumulated Depreciation		$ 14,394
Year(s) built / renovated		1983/1998/2013
Depreciable Lives (Years)	[2]	-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		18,800
Land and improvements		13,593
Buildings and Improvements		68,219
Land Held for Development		0
Development and Construction in Progress		0
Total		81,812
Accumulated Depreciation		$ 20,265
Year(s) built / renovated		1992
Depreciable Lives (Years)	[2]	-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		5,605
Land and improvements		13,873
Buildings and Improvements		65,962
Land Held for Development		0
Development and Construction in Progress		0
Total		79,835
Accumulated Depreciation		$ 18,930
Year(s) built / renovated		2008
Depreciable Lives (Years)	[2]	-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		8,907
Land and improvements		11,097
Buildings and Improvements		68,889
Land Held for Development		0
Development and Construction in Progress		0
Total		79,986
Accumulated Depreciation		$ 24,699
Year(s) built / renovated		2003
Depreciable Lives (Years)	[2]	-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		4,028
Land and improvements		23,377
Buildings and Improvements		16,214
Land Held for Development		35,908
Development and Construction in Progress		0
Total		75,499
Accumulated Depreciation		$ 14,139
Year(s) built / renovated		1981
Depreciable Lives (Years)	[2]	-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		$ 4,375
Year(s) built / renovated		2013
Depreciable Lives (Years)	[2]	(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		1,422
Land and improvements		16,741
Buildings and Improvements		52,707
Land Held for Development		0
Development and Construction in Progress		0
Total		69,448
Accumulated Depreciation		$ 8,185
Year(s) built / renovated		1987/2003
Depreciable Lives (Years)	[2]	-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		12,787
Land and improvements		0
Buildings and Improvements		66,136
Land Held for Development		0
Development and Construction in Progress		0
Total		66,136
Accumulated Depreciation		$ 18,272
Year(s) built / renovated		2009
Depreciable Lives (Years)	[2]	-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		6,464
Land and improvements		10,148
Buildings and Improvements		56,308
Land Held for Development		0
Development and Construction in Progress		0
Total		66,456
Accumulated Depreciation		$ 23,962
Year(s) built / renovated		1984
Depreciable Lives (Years)	[2]	-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		3,911
Land and improvements		6,510
Buildings and Improvements		54,853
Land Held for Development		0
Development and Construction in Progress		0
Total		61,363
Accumulated Depreciation		$ 20,110
Year(s) built / renovated		2004
Depreciable Lives (Years)	[2]	-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		26,196
Land and improvements		1,478
Buildings and Improvements		54,087
Land Held for Development		0
Development and Construction in Progress		0
Total		55,565
Accumulated Depreciation		$ 26,923
Year(s) built / renovated		1985
Depreciable Lives (Years)	[2]	-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		$ 18,034
Year(s) built / renovated		1999
Depreciable Lives (Years)	[2]	-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		$ 38,494
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		$ 22,760
Year(s) built / renovated		2001
Depreciable Lives (Years)	[2]	-1
191 Spring Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		191 Spring Street
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		2,850
Original Building		27,166
Costs Capitalized Subsequent to Acquisition		18,610
Land and improvements		3,151
Buildings and Improvements		45,475
Land Held for Development		0
Development and Construction in Progress		0
Total		48,626
Accumulated Depreciation		$ 32,535
Year(s) built / renovated		1971/1995
Depreciable Lives (Years)	[2]	-1
University Place
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		University Place
Type		Office
Location		Cambridge, MA
Encumbrances		$ 10,788
Original Land		0
Original Building		37,091
Costs Capitalized Subsequent to Acquisition		9,483
Land and improvements		390
Buildings and Improvements		46,184
Land Held for Development		0
Development and Construction in Progress		0
Total		46,574
Accumulated Depreciation		$ 23,635
Year(s) built / renovated		1985
Depreciable Lives (Years)	[2]	-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		18,559
Land and improvements		548
Buildings and Improvements		43,255
Land Held for Development		0
Development and Construction in Progress		0
Total		43,803
Accumulated Depreciation		$ 27,153
Year(s) built / renovated		1987
Depreciable Lives (Years)	[2]	-1
Quorum Office Park
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		8,656
Land and improvements		4,785
Buildings and Improvements		39,239
Land Held for Development		0
Development and Construction in Progress		0
Total		44,024
Accumulated Depreciation		$ 18,386
Year(s) built / renovated		2001
Depreciable Lives (Years)	[2]	-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		5,814
Land and improvements		5,187
Buildings and Improvements		36,831
Land Held for Development		0
Development and Construction in Progress		0
Total		42,018
Accumulated Depreciation		$ 14,671
Year(s) built / renovated		2001
Depreciable Lives (Years)	[2]	-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		$ 14,073
Year(s) built / renovated		1999
Depreciable Lives (Years)	[2]	-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		13,144
Land and improvements		2,379
Buildings and Improvements		33,294
Land Held for Development		0
Development and Construction in Progress		0
Total		35,673
Accumulated Depreciation		$ 22,616
Year(s) built / renovated		1987
Depreciable Lives (Years)	[2]	-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		12,368
Land and improvements		965
Buildings and Improvements		23,777
Land Held for Development		0
Development and Construction in Progress		0
Total		24,742
Accumulated Depreciation		$ 11,339
Year(s) built / renovated		1987/2013
Depreciable Lives (Years)	[2]	-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		7,177
Land and improvements		2,395
Buildings and Improvements		19,024
Land Held for Development		0
Development and Construction in Progress		0
Total		21,419
Accumulated Depreciation		$ 12,556
Year(s) built / renovated		1990
Depreciable Lives (Years)	[2]	-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		3,184
Land and improvements		893
Buildings and Improvements		17,740
Land Held for Development		0
Development and Construction in Progress		0
Total		18,633
Accumulated Depreciation		$ 6,846
Year(s) built / renovated		2001
Depreciable Lives (Years)	[2]	-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		16,099
Land and improvements		1,264
Buildings and Improvements		17,259
Land Held for Development		0
Development and Construction in Progress		0
Total		18,523
Accumulated Depreciation		$ 11,730
Year(s) built / renovated		1982
Depreciable Lives (Years)	[2]	-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		(154)
Land and improvements		3,124
Buildings and Improvements		14,874
Land Held for Development		0
Development and Construction in Progress		0
Total		17,998
Accumulated Depreciation		$ 6,987
Year(s) built / renovated		1997
Depreciable Lives (Years)	[2]	-1
The Point (formerly 99 Third Avenue Retail)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		The Point (formerly 99 Third Avenue Retail)
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		6,395
Original Building		10,040
Costs Capitalized Subsequent to Acquisition		0
Land and improvements		6,395
Buildings and Improvements		10,040
Land Held for Development		0
Development and Construction in Progress		0
Total		16,435
Accumulated Depreciation		$ 76
Year(s) built / renovated		2015
Depreciable Lives (Years)	[2]	-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		8,192
Land and improvements		941
Buildings and Improvements		14,499
Land Held for Development		0
Development and Construction in Progress		0
Total		15,440
Accumulated Depreciation		$ 8,525
Year(s) built / renovated		1985
Depreciable Lives (Years)	[2]	-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		8,034
Land and improvements		802
Buildings and Improvements		14,574
Land Held for Development		0
Development and Construction in Progress		0
Total		15,376
Accumulated Depreciation		$ 11,412
Year(s) built / renovated		1985
Depreciable Lives (Years)	[2]	-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		0
Land and improvements		3,219
Buildings and Improvements		11,038
Land Held for Development		0
Development and Construction in Progress		0
Total		14,257
Accumulated Depreciation		$ 334
Year(s) built / renovated		2015
Depreciable Lives (Years)	[2]	-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		1,993
Land and improvements		1,160
Buildings and Improvements		11,419
Land Held for Development		0
Development and Construction in Progress		0
Total		12,579
Accumulated Depreciation		$ 4,580
Year(s) built / renovated		1999
Depreciable Lives (Years)	[2]	-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		$ 6,586
Year(s) built / renovated		1979
Depreciable Lives (Years)	[2]	-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		$ 7,071
Year(s) built / renovated		1990
Depreciable Lives (Years)	[2]	-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		5,305
Land and improvements		324
Buildings and Improvements		10,637
Land Held for Development		0
Development and Construction in Progress		0
Total		10,961
Accumulated Depreciation		$ 7,864
Year(s) built / renovated		1984
Depreciable Lives (Years)	[2]	-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		520
Land and improvements		791
Buildings and Improvements		9,667
Land Held for Development		0
Development and Construction in Progress		0
Total		10,458
Accumulated Depreciation		$ 4,355
Year(s) built / renovated		1997
Depreciable Lives (Years)	[2]	-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		4,218
Land and improvements		659
Buildings and Improvements		7,773
Land Held for Development		0
Development and Construction in Progress		0
Total		8,432
Accumulated Depreciation		$ 6,052
Year(s) built / renovated		1982
Depreciable Lives (Years)	[2]	-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		$ 4,303
Year(s) built / renovated		1983
Depreciable Lives (Years)	[2]	-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		1,880
Land and improvements		1,430
Buildings and Improvements		6,296
Land Held for Development		0
Development and Construction in Progress		0
Total		7,726
Accumulated Depreciation		$ 3,226
Year(s) built / renovated		1987
Depreciable Lives (Years)	[2]	-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		235
Land and improvements		5,479
Buildings and Improvements		1,323
Land Held for Development		0
Development and Construction in Progress		0
Total		6,802
Accumulated Depreciation		$ 265
Year(s) built / renovated		1977
Depreciable Lives (Years)	[2]	-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		2,684
Land and improvements		601
Buildings and Improvements		6,731
Land Held for Development		0
Development and Construction in Progress		0
Total		7,332
Accumulated Depreciation		$ 5,336
Year(s) built / renovated		1984
Depreciable Lives (Years)	[2]	-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		2,617
Land and improvements		406
Buildings and Improvements		6,098
Land Held for Development		0
Development and Construction in Progress		0
Total		6,504
Accumulated Depreciation		$ 4,499
Year(s) built / renovated		1985
Depreciable Lives (Years)	[2]	-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		$ 4,626
Year(s) built / renovated		2002
Depreciable Lives (Years)	[2]	-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		4,924
Land and improvements		551
Buildings and Improvements		5,451
Land Held for Development		0
Development and Construction in Progress		0
Total		6,002
Accumulated Depreciation		$ 3,849
Year(s) built / renovated		1986
Depreciable Lives (Years)	[2]	-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		$ 2,639
Year(s) built / renovated		1989
Depreciable Lives (Years)	[2]	-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		1,003
Land and improvements		93
Buildings and Improvements		3,618
Land Held for Development		0
Development and Construction in Progress		0
Total		3,711
Accumulated Depreciation		$ 2,464
Year(s) built / renovated		1988
Depreciable Lives (Years)	[2]	-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		1,735
Land and improvements		398
Buildings and Improvements		3,183
Land Held for Development		0
Development and Construction in Progress		0
Total		3,581
Accumulated Depreciation		$ 2,345
Year(s) built / renovated		1984
Depreciable Lives (Years)	[2]	-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		1,661
Land and improvements		613
Buildings and Improvements		2,839
Land Held for Development		0
Development and Construction in Progress		0
Total		3,452
Accumulated Depreciation		$ 2,233
Year(s) built / renovated		1982
Depreciable Lives (Years)	[2]	-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		1,193
Land and improvements		314
Buildings and Improvements		2,990
Land Held for Development		0
Development and Construction in Progress		0
Total		3,304
Accumulated Depreciation		$ 1,786
Year(s) built / renovated		1968-1979/1987
Depreciable Lives (Years)	[2]	-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		$ 786
Year(s) built / renovated		1982
Depreciable Lives (Years)	[2]	-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		614
Land and improvements		65
Buildings and Improvements		725
Land Held for Development		0
Development and Construction in Progress		0
Total		790
Accumulated Depreciation		$ 323
Year(s) built / renovated		1968
Depreciable Lives (Years)	[2]	-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		813
Land and improvements		20,350
Buildings and Improvements		92,808
Land Held for Development		0
Development and Construction in Progress		0
Total		113,158
Accumulated Depreciation		$ 4,833
Year(s) built / renovated		2014
Depreciable Lives (Years)	[2]	-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		1,579
Land and improvements		3,529
Buildings and Improvements		56,470
Land Held for Development		0
Development and Construction in Progress		0
Total		59,999
Accumulated Depreciation		$ 6,596
Year(s) built / renovated		2011
Depreciable Lives (Years)	[2]	-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		35,665
Land and improvements		1,201
Buildings and Improvements		72,860
Land Held for Development		0
Development and Construction in Progress		0
Total		74,061
Accumulated Depreciation		$ 48,162
Year(s) built / renovated		1986
Depreciable Lives (Years)	[2]	-1
Kendall Center Green Garage (formerly Cambridge Center East Garage)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Green Garage (formerly Cambridge Center East Garage)
Type		Garage
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		0
Original Building		35,035
Costs Capitalized Subsequent to Acquisition		4,254
Land and improvements		103
Buildings and Improvements		39,186
Land Held for Development		0
Development and Construction in Progress		0
Total		39,289
Accumulated Depreciation		$ 8,610
Year(s) built / renovated		1984
Depreciable Lives (Years)	[2]	-1
Kendall Center Yellow Garage (formerly Cambridge Center West Garage)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Yellow Garage (formerly Cambridge Center West 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		$ 4,269
Year(s) built / renovated		2006
Depreciable Lives (Years)	[2]	-1
Kendall Center Blue Garage (formerly Cambridge Center North Garage)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Blue Garage (formerly Cambridge Center North 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		$ 8,941
Year(s) built / renovated		1990
Depreciable Lives (Years)	[2]	-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		429,767
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		0
Development and Construction in Progress		429,767
Total		429,767
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
601 Massachusetts Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		601 Massachusetts Avenue
Type		Development
Location		Washington, DC
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		253,176
Land and improvements		95,322
Buildings and Improvements		140,791
Land Held for Development		0
Development and Construction in Progress		17,063
Total		253,176
Accumulated Depreciation		$ 1,531
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
10 CityPoint
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		10 CityPoint
Type		Development
Location		Waltham, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		70,389
Land and improvements		163
Buildings and Improvements		0
Land Held for Development		0
Development and Construction in Progress		70,226
Total		70,389
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Reston Signature Site
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Reston Signature Site
Type		Development
Location		Reston, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		38,886
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		12,678
Development and Construction in Progress		26,208
Total		38,886
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Cambridge Residential / 88 Ames
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Cambridge Residential / 88 Ames
Type		Development
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		9,495
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		0
Development and Construction in Progress		9,495
Total		9,495
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
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		34,870
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		34,870
Development and Construction in Progress		0
Total		34,870
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
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		29,022
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		29,022
Development and Construction in Progress		0
Total		29,022
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
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		29,010
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		29,010
Development and Construction in Progress		0
Total		29,010
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
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
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		13,415
Land and improvements		0
Buildings and Improvements		132
Land Held for Development		13,283
Development and Construction in Progress		0
Total		13,415
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
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		11,927
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		11,927
Development and Construction in Progress		0
Total		11,927
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
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		10,294
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		10,294
Development and Construction in Progress		0
Total		10,294
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
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		10,258
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		10,258
Development and Construction in Progress		0
Total		10,258
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
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		9,215
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		9,215
Development and Construction in Progress		0
Total		9,215
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
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		8,836
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		8,836
Development and Construction in Progress		0
Total		8,836
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
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		8,727
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		8,727
Development and Construction in Progress		0
Total		8,727
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
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		6,399
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		6,399
Development and Construction in Progress		0
Total		6,399
Accumulated Depreciation		$ 0
Year(s) built / renovated		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		2,999
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		2,999
Development and Construction in Progress		0
Total		2,999
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Fourth and Harrison (formerly 425 Fourth Street)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Fourth and Harrison (formerly 425 Fourth Street)
Type		Land
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		2,920
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		2,920
Development and Construction in Progress		0
Total		2,920
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Kendall Center Master Plan (formerly Cambridge Master Plan)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Master Plan (formerly Cambridge Master Plan)
Type		Land
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		1,403
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		1,403
Development and Construction in Progress		0
Total		1,403
Accumulated Depreciation		$ 0
Year(s) built / renovated		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		1,213
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		1,213
Development and Construction in Progress		0
Total		1,213
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Encumbrances	[3]	$ 3,438,714
Original Land		4,602,809
Original Building		11,248,289
Costs Capitalized Subsequent to Acquisition		3,180,191
Land and improvements		4,700,793
Buildings and Improvements		13,314,366
Land Held for Development		252,195
Development and Construction in Progress		763,935
Total		19,031,289
Accumulated Depreciation		3,826,862
Furniture, fixtures and equipment		29,852	$ 27,986
Furniture, fixtures and equipment accumulated depreciation		19,954
Real Estate Aggregate Cost For Tax Purposes		16,800,000
Real Estate Aggregate Accumulated Depreciation For Tax Purposes		$ 3,400,000
Real Estate and Accumulated Depreciation, Life Used for Depreciation		40 years
Unamortized balance of historical fair value adjustments		$ 80,200
Boston Properties Limited Partnership [Member] | 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		$ 1,377,986
Original Land		1,796,252
Original Building		1,532,654
Costs Capitalized Subsequent to Acquisition		45,800
Land and improvements		1,796,252
Buildings and Improvements		1,578,454
Land Held for Development		0
Development and Construction in Progress		0
Total		3,374,706
Accumulated Depreciation		$ 128,488
Year(s) built / renovated		1968
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		466,370
Land and improvements		92,328
Buildings and Improvements		1,037,311
Land Held for Development		1,714
Development and Construction in Progress		161,688
Total		1,293,041
Accumulated Depreciation		$ 435,437
Year(s) built / renovated		1965/1993/2002
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | Embarcadero Center
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Embarcadero Center
Type		Office
Location		San Francisco, CA
Encumbrances		$ 348,886
Original Land		179,697
Original Building		847,410
Costs Capitalized Subsequent to Acquisition		269,895
Land and improvements		180,420
Buildings and Improvements		1,116,582
Land Held for Development		0
Development and Construction in Progress		0
Total		1,297,002
Accumulated Depreciation		$ 530,307
Year(s) built / renovated		1970/1989
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		51,364
Land and improvements		339,200
Buildings and Improvements		751,722
Land Held for Development		0
Development and Construction in Progress		0
Total		1,090,922
Accumulated Depreciation		$ 254,028
Year(s) built / renovated		1961
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 200 Clarendon Street and Garage (formerly The John Hancock Tower and Garage)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		200 Clarendon Street and Garage (formerly the John Hancock Tower and Garage)
Type		Office
Location		Boston, MA
Encumbrances		$ 0
Original Land		219,543
Original Building		667,884
Costs Capitalized Subsequent to Acquisition		112,229
Land and improvements		219,616
Buildings and Improvements		776,755
Land Held for Development		3,285
Development and Construction in Progress		0
Total		999,656
Accumulated Depreciation		$ 128,815
Year(s) built / renovated		1976
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		$ 699,061
Original Land		241,600
Original Building		494,782
Costs Capitalized Subsequent to Acquisition		190,393
Land and improvements		279,281
Buildings and Improvements		646,177
Land Held for Development		1,317
Development and Construction in Progress		0
Total		926,775
Accumulated Depreciation		$ 242,358
Year(s) built / renovated		1977/1997
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		16,488
Land and improvements		285,263
Buildings and Improvements		619,655
Land Held for Development		0
Development and Construction in Progress		0
Total		904,918
Accumulated Depreciation		$ 28,349
Year(s) built / renovated		2014
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		110,751
Land and improvements		98,733
Buildings and Improvements		451,099
Land Held for Development		2,475
Development and Construction in Progress		40,810
Total		593,117
Accumulated Depreciation		$ 195,128
Year(s) built / renovated		1983-1999
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		46,743
Land and improvements		159,694
Buildings and Improvements		432,900
Land Held for Development		0
Development and Construction in Progress		0
Total		592,594
Accumulated Depreciation		$ 157,622
Year(s) built / renovated		2004
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		15,555
Land and improvements		131,067
Buildings and Improvements		450,933
Land Held for Development		576
Development and Construction in Progress		0
Total		582,576
Accumulated Depreciation		$ 60,125
Year(s) built / renovated		1971-1975
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		16,376
Land and improvements		63,988
Buildings and Improvements		470,913
Land Held for Development		0
Development and Construction in Progress		0
Total		534,901
Accumulated Depreciation		$ 70,552
Year(s) built / renovated		2011
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		19,575
Land and improvements		103,000
Buildings and Improvements		273,240
Land Held for Development		0
Development and Construction in Progress		0
Total		376,240
Accumulated Depreciation		$ 34,640
Year(s) built / renovated		2012
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | Fountain Square
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Fountain Square
Type		Office
Location		Reston, VA
Encumbrances		$ 213,499
Original Land		56,853
Original Building		306,298
Costs Capitalized Subsequent to Acquisition		12,459
Land and improvements		56,853
Buildings and Improvements		318,757
Land Held for Development		0
Development and Construction in Progress		0
Total		375,610
Accumulated Depreciation		$ 39,508
Year(s) built / renovated		1986-1990
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		$ 750,000
Original Land		81,040
Original Building		100,507
Costs Capitalized Subsequent to Acquisition		122,309
Land and improvements		81,040
Buildings and Improvements		222,816
Land Held for Development		0
Development and Construction in Progress		0
Total		303,856
Accumulated Depreciation		$ 155,235
Year(s) built / renovated		1986
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		7,348
Land and improvements		72,545
Buildings and Improvements		227,114
Land Held for Development		0
Development and Construction in Progress		0
Total		299,659
Accumulated Depreciation		$ 13,091
Year(s) built / renovated		2014
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		11,641
Land and improvements		13,603
Buildings and Improvements		249,120
Land Held for Development		0
Development and Construction in Progress		0
Total		262,723
Accumulated Depreciation		$ 70,389
Year(s) built / renovated		2008-2009
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		65,997
Land and improvements		18,789
Buildings and Improvements		214,448
Land Held for Development		0
Development and Construction in Progress		0
Total		233,237
Accumulated Depreciation		$ 40,812
Year(s) built / renovated		1985-1989
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		47,638
Land and improvements		29,029
Buildings and Improvements		186,109
Land Held for Development		0
Development and Construction in Progress		0
Total		215,138
Accumulated Depreciation		$ 92,882
Year(s) built / renovated		1984/1986/2002
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		0
Land and improvements		40,933
Buildings and Improvements		148,378
Land Held for Development		0
Development and Construction in Progress		0
Total		189,311
Accumulated Depreciation		$ 3,221
Year(s) built / renovated		2015
Depreciable Lives (Years)	[4]	(1)
Boston Properties Limited Partnership [Member] | 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		5,230
Land and improvements		0
Buildings and Improvements		188,771
Land Held for Development		0
Development and Construction in Progress		0
Total		188,771
Accumulated Depreciation		$ 33,039
Year(s) built / renovated		2011
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		5,581
Land and improvements		95,066
Buildings and Improvements		73,954
Land Held for Development		0
Development and Construction in Progress		0
Total		169,020
Accumulated Depreciation		$ 9,581
Year(s) built / renovated		1977-1981/2007-2013
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		42,472
Land and improvements		19,099
Buildings and Improvements		125,919
Land Held for Development		0
Development and Construction in Progress		8,678
Total		153,696
Accumulated Depreciation		$ 56,939
Year(s) built / renovated		1955/1987
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		1,112
Land and improvements		18,021
Buildings and Improvements		110,150
Land Held for Development		0
Development and Construction in Progress		0
Total		128,171
Accumulated Depreciation		$ 33,350
Year(s) built / renovated		2003-2006
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		5,447
Land and improvements		34,032
Buildings and Improvements		91,107
Land Held for Development		0
Development and Construction in Progress		0
Total		125,139
Accumulated Depreciation		$ 34,441
Year(s) built / renovated		1996
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		14,485
Land and improvements		25,982
Buildings and Improvements		96,796
Land Held for Development		0
Development and Construction in Progress		0
Total		122,778
Accumulated Depreciation		$ 44,193
Year(s) built / renovated		1984
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		$ 17,023
Year(s) built / renovated		2010
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		78,438
Land and improvements		6,128
Buildings and Improvements		106,600
Land Held for Development		0
Development and Construction in Progress		0
Total		112,728
Accumulated Depreciation		$ 55,581
Year(s) built / renovated		1981/2006
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		13,976
Land and improvements		9,883
Buildings and Improvements		98,526
Land Held for Development		0
Development and Construction in Progress		0
Total		108,409
Accumulated Depreciation		$ 40,044
Year(s) built / renovated		2000
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		15,162
Land and improvements		13,866
Buildings and Improvements		92,965
Land Held for Development		0
Development and Construction in Progress		0
Total		106,831
Accumulated Depreciation		$ 39,996
Year(s) built / renovated		2001
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 415 Main Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		415 Main Street
Type		Office
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		3,457
Original Building		97,136
Costs Capitalized Subsequent to Acquisition		316
Land and improvements		3,457
Buildings and Improvements		97,452
Land Held for Development		0
Development and Construction in Progress		0
Total		100,909
Accumulated Depreciation		$ 58,907
Year(s) built / renovated		2006
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		28,524
Land and improvements		21,098
Buildings and Improvements		79,635
Land Held for Development		0
Development and Construction in Progress		0
Total		100,733
Accumulated Depreciation		$ 23,319
Year(s) built / renovated		1981/1996/2013
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		17,967
Land and improvements		15,074
Buildings and Improvements		85,541
Land Held for Development		0
Development and Construction in Progress		0
Total		100,615
Accumulated Depreciation		$ 36,334
Year(s) built / renovated		1999
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		15,689
Land and improvements		11,146
Buildings and Improvements		87,523
Land Held for Development		0
Development and Construction in Progress		0
Total		98,669
Accumulated Depreciation		$ 34,789
Year(s) built / renovated		2001
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		11,085
Land and improvements		18,095
Buildings and Improvements		77,990
Land Held for Development		0
Development and Construction in Progress		0
Total		96,085
Accumulated Depreciation		$ 22,441
Year(s) built / renovated		2000
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		17,207
Land and improvements		20,741
Buildings and Improvements		67,648
Land Held for Development		0
Development and Construction in Progress		0
Total		88,389
Accumulated Depreciation		$ 14,366
Year(s) built / renovated		1983/1998/2013
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		17,183
Land and improvements		13,189
Buildings and Improvements		67,006
Land Held for Development		0
Development and Construction in Progress		0
Total		80,195
Accumulated Depreciation		$ 19,965
Year(s) built / renovated		1992
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		5,500
Land and improvements		13,847
Buildings and Improvements		65,883
Land Held for Development		0
Development and Construction in Progress		0
Total		79,730
Accumulated Depreciation		$ 18,914
Year(s) built / renovated		2008
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		5,920
Land and improvements		10,350
Buildings and Improvements		66,649
Land Held for Development		0
Development and Construction in Progress		0
Total		76,999
Accumulated Depreciation		$ 24,136
Year(s) built / renovated		2003
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		4,005
Land and improvements		23,371
Buildings and Improvements		16,197
Land Held for Development		35,908
Development and Construction in Progress		0
Total		75,476
Accumulated Depreciation		$ 14,139
Year(s) built / renovated		1981
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		$ 4,375
Year(s) built / renovated		2013
Depreciable Lives (Years)	[4]	(1)
Boston Properties Limited Partnership [Member] | 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		1,422
Land and improvements		16,741
Buildings and Improvements		52,707
Land Held for Development		0
Development and Construction in Progress		0
Total		69,448
Accumulated Depreciation		$ 8,185
Year(s) built / renovated		1987/2003
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		12,787
Land and improvements		0
Buildings and Improvements		66,136
Land Held for Development		0
Development and Construction in Progress		0
Total		66,136
Accumulated Depreciation		$ 18,272
Year(s) built / renovated		2009
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		3,853
Land and improvements		9,496
Buildings and Improvements		54,349
Land Held for Development		0
Development and Construction in Progress		0
Total		63,845
Accumulated Depreciation		$ 23,471
Year(s) built / renovated		1984
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		166
Land and improvements		5,574
Buildings and Improvements		52,044
Land Held for Development		0
Development and Construction in Progress		0
Total		57,618
Accumulated Depreciation		$ 19,401
Year(s) built / renovated		2004
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		24,116
Land and improvements		958
Buildings and Improvements		52,527
Land Held for Development		0
Development and Construction in Progress		0
Total		53,485
Accumulated Depreciation		$ 26,534
Year(s) built / renovated		1985
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		$ 17,532
Year(s) built / renovated		1999
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		$ 38,494
Original Land		3,880
Original Building		43,227
Costs Capitalized Subsequent to Acquisition		1,074
Land and improvements		3,880
Buildings and Improvements		44,301
Land Held for Development		0
Development and Construction in Progress		0
Total		48,181
Accumulated Depreciation		$ 22,230
Year(s) built / renovated		2001
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 191 Spring Street
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		191 Spring Street
Type		Office
Location		Lexington, MA
Encumbrances		$ 0
Original Land		2,850
Original Building		27,166
Costs Capitalized Subsequent to Acquisition		17,411
Land and improvements		2,850
Buildings and Improvements		44,577
Land Held for Development		0
Development and Construction in Progress		0
Total		47,427
Accumulated Depreciation		$ 32,307
Year(s) built / renovated		1971/1995
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | University Place
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		University Place
Type		Office
Location		Cambridge, MA
Encumbrances		$ 10,788
Original Land		0
Original Building		37,091
Costs Capitalized Subsequent to Acquisition		8,033
Land and improvements		27
Buildings and Improvements		45,097
Land Held for Development		0
Development and Construction in Progress		0
Total		45,124
Accumulated Depreciation		$ 23,365
Year(s) built / renovated		1985
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		16,903
Land and improvements		134
Buildings and Improvements		42,013
Land Held for Development		0
Development and Construction in Progress		0
Total		42,147
Accumulated Depreciation		$ 26,843
Year(s) built / renovated		1987
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | Quorum Office Park
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		6,493
Land and improvements		4,244
Buildings and Improvements		37,617
Land Held for Development		0
Development and Construction in Progress		0
Total		41,861
Accumulated Depreciation		$ 17,977
Year(s) built / renovated		2001
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		$ 14,352
Year(s) built / renovated		2001
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		$ 13,693
Year(s) built / renovated		1999
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		9,904
Land and improvements		1,569
Buildings and Improvements		30,864
Land Held for Development		0
Development and Construction in Progress		0
Total		32,433
Accumulated Depreciation		$ 22,008
Year(s) built / renovated		1987
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		11,597
Land and improvements		772
Buildings and Improvements		23,199
Land Held for Development		0
Development and Construction in Progress		0
Total		23,971
Accumulated Depreciation		$ 11,192
Year(s) built / renovated		1987/2013
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		5,071
Land and improvements		1,868
Buildings and Improvements		17,445
Land Held for Development		0
Development and Construction in Progress		0
Total		19,313
Accumulated Depreciation		$ 12,158
Year(s) built / renovated		1990
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		2,448
Land and improvements		709
Buildings and Improvements		17,188
Land Held for Development		0
Development and Construction in Progress		0
Total		17,897
Accumulated Depreciation		$ 6,707
Year(s) built / renovated		2001
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		15,335
Land and improvements		1,073
Buildings and Improvements		16,686
Land Held for Development		0
Development and Construction in Progress		0
Total		17,759
Accumulated Depreciation		$ 11,589
Year(s) built / renovated		1982
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		(1,253)
Land and improvements		2,849
Buildings and Improvements		14,050
Land Held for Development		0
Development and Construction in Progress		0
Total		16,899
Accumulated Depreciation		$ 6,779
Year(s) built / renovated		1997
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | The Point (formerly 99 Third Avenue Retail)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		The Point (formerly 99 Third Avenue Retail)
Type		Office
Location		Waltham, MA
Encumbrances		$ 0
Original Land		6,395
Original Building		10,040
Costs Capitalized Subsequent to Acquisition		0
Land and improvements		6,395
Buildings and Improvements		10,040
Land Held for Development		0
Development and Construction in Progress		0
Total		16,435
Accumulated Depreciation		$ 76
Year(s) built / renovated		2015
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		7,565
Land and improvements		784
Buildings and Improvements		14,029
Land Held for Development		0
Development and Construction in Progress		0
Total		14,813
Accumulated Depreciation		$ 8,405
Year(s) built / renovated		1985
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		7,305
Land and improvements		619
Buildings and Improvements		14,028
Land Held for Development		0
Development and Construction in Progress		0
Total		14,647
Accumulated Depreciation		$ 11,274
Year(s) built / renovated		1985
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		0
Land and improvements		3,219
Buildings and Improvements		11,038
Land Held for Development		0
Development and Construction in Progress		0
Total		14,257
Accumulated Depreciation		$ 334
Year(s) built / renovated		2015
Depreciable Lives (Years)	[4]	(1)
Boston Properties Limited Partnership [Member] | 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		1,616
Land and improvements		1,066
Buildings and Improvements		11,136
Land Held for Development		0
Development and Construction in Progress		0
Total		12,202
Accumulated Depreciation		$ 4,509
Year(s) built / renovated		1999
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		$ 6,466
Year(s) built / renovated		1979
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		$ 6,882
Year(s) built / renovated		1990
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		4,492
Land and improvements		121
Buildings and Improvements		10,027
Land Held for Development		0
Development and Construction in Progress		0
Total		10,148
Accumulated Depreciation		$ 7,713
Year(s) built / renovated		1984
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		15
Land and improvements		665
Buildings and Improvements		9,288
Land Held for Development		0
Development and Construction in Progress		0
Total		9,953
Accumulated Depreciation		$ 4,259
Year(s) built / renovated		1997
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		3,525
Land and improvements		486
Buildings and Improvements		7,253
Land Held for Development		0
Development and Construction in Progress		0
Total		7,739
Accumulated Depreciation		$ 5,922
Year(s) built / renovated		1982
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		$ 4,183
Year(s) built / renovated		1983
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		1,466
Land and improvements		1,327
Buildings and Improvements		5,985
Land Held for Development		0
Development and Construction in Progress		0
Total		7,312
Accumulated Depreciation		$ 3,145
Year(s) built / renovated		1987
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		233
Land and improvements		5,477
Buildings and Improvements		1,323
Land Held for Development		0
Development and Construction in Progress		0
Total		6,800
Accumulated Depreciation		$ 265
Year(s) built / renovated		1977
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		2,090
Land and improvements		453
Buildings and Improvements		6,285
Land Held for Development		0
Development and Construction in Progress		0
Total		6,738
Accumulated Depreciation		$ 5,225
Year(s) built / renovated		1984
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		2,084
Land and improvements		273
Buildings and Improvements		5,698
Land Held for Development		0
Development and Construction in Progress		0
Total		5,971
Accumulated Depreciation		$ 4,399
Year(s) built / renovated		1985
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		$ 4,586
Year(s) built / renovated		2002
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		4,231
Land and improvements		378
Buildings and Improvements		4,931
Land Held for Development		0
Development and Construction in Progress		0
Total		5,309
Accumulated Depreciation		$ 3,719
Year(s) built / renovated		1986
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		$ 2,570
Year(s) built / renovated		1989
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		822
Land and improvements		47
Buildings and Improvements		3,483
Land Held for Development		0
Development and Construction in Progress		0
Total		3,530
Accumulated Depreciation		$ 2,432
Year(s) built / renovated		1988
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		1,352
Land and improvements		303
Buildings and Improvements		2,895
Land Held for Development		0
Development and Construction in Progress		0
Total		3,198
Accumulated Depreciation		$ 2,275
Year(s) built / renovated		1984
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		1,348
Land and improvements		535
Buildings and Improvements		2,604
Land Held for Development		0
Development and Construction in Progress		0
Total		3,139
Accumulated Depreciation		$ 2,173
Year(s) built / renovated		1982
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		607
Land and improvements		168
Buildings and Improvements		2,550
Land Held for Development		0
Development and Construction in Progress		0
Total		2,718
Accumulated Depreciation		$ 1,674
Year(s) built / renovated		1968-1979/1987
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		$ 745
Year(s) built / renovated		1982
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		457
Land and improvements		26
Buildings and Improvements		607
Land Held for Development		0
Development and Construction in Progress		0
Total		633
Accumulated Depreciation		$ 293
Year(s) built / renovated		1968
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		813
Land and improvements		20,350
Buildings and Improvements		92,808
Land Held for Development		0
Development and Construction in Progress		0
Total		113,158
Accumulated Depreciation		$ 4,833
Year(s) built / renovated		2014
Depreciable Lives (Years)	[4]	(1)
Boston Properties Limited Partnership [Member] | 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		1,579
Land and improvements		3,529
Buildings and Improvements		56,470
Land Held for Development		0
Development and Construction in Progress		0
Total		59,999
Accumulated Depreciation		$ 6,596
Year(s) built / renovated		2011
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		32,774
Land and improvements		478
Buildings and Improvements		70,692
Land Held for Development		0
Development and Construction in Progress		0
Total		71,170
Accumulated Depreciation		$ 47,620
Year(s) built / renovated		1986
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | Kendall Center Green Garage (formerly Cambridge Center East Garage)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Green Garage (formerly Cambridge Center East Garage)
Type		Garage
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		0
Original Building		35,035
Costs Capitalized Subsequent to Acquisition		3,840
Land and improvements		0
Buildings and Improvements		38,875
Land Held for Development		0
Development and Construction in Progress		0
Total		38,875
Accumulated Depreciation		$ 8,534
Year(s) built / renovated		1984
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | Kendall Center Yellow Garage (formerly Cambridge Center West Garage)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Yellow Garage (formerly Cambridge Center West 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		$ 4,140
Year(s) built / renovated		2006
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | Kendall Center Blue Garage (formerly Cambridge Center North Garage)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Blue Garage (formerly Cambridge Center North 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		$ 8,630
Year(s) built / renovated		1990
Depreciable Lives (Years)	[4]	-1
Boston Properties Limited Partnership [Member] | 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		429,767
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		0
Development and Construction in Progress		429,767
Total		429,767
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | 601 Massachusetts Avenue
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		601 Massachusetts Avenue
Type		Development
Location		Washington, DC
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		253,166
Land and improvements		95,312
Buildings and Improvements		140,791
Land Held for Development		0
Development and Construction in Progress		17,063
Total		253,166
Accumulated Depreciation		$ 1,531
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | 10 CityPoint
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		10 CityPoint
Type		Development
Location		Waltham, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		70,226
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		0
Development and Construction in Progress		70,226
Total		70,226
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | Reston Signature Site
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Reston Signature Site
Type		Development
Location		Reston, VA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		38,886
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		12,678
Development and Construction in Progress		26,208
Total		38,886
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | Cambridge Residential / 88 Ames
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Cambridge Residential / 88 Ames
Type		Development
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		9,495
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		0
Development and Construction in Progress		9,495
Total		9,495
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | 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		34,870
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		34,870
Development and Construction in Progress		0
Total		34,870
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | 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		29,022
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		29,022
Development and Construction in Progress		0
Total		29,022
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | 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		29,010
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		29,010
Development and Construction in Progress		0
Total		29,010
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | 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
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | 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		13,415
Land and improvements		0
Buildings and Improvements		132
Land Held for Development		13,283
Development and Construction in Progress		0
Total		13,415
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | 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		11,927
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		11,927
Development and Construction in Progress		0
Total		11,927
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | 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		10,294
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		10,294
Development and Construction in Progress		0
Total		10,294
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | 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		10,258
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		10,258
Development and Construction in Progress		0
Total		10,258
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | 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		9,215
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		9,215
Development and Construction in Progress		0
Total		9,215
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | 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		8,836
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		8,836
Development and Construction in Progress		0
Total		8,836
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | 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		8,727
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		8,727
Development and Construction in Progress		0
Total		8,727
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | 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		6,399
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		6,399
Development and Construction in Progress		0
Total		6,399
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | 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		2,999
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		2,999
Development and Construction in Progress		0
Total		2,999
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | Fourth and Harrison (formerly 425 Fourth Street)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Fourth and Harrison (formerly 425 Fourth Street)
Type		Land
Location		San Francisco, CA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		2,920
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		2,920
Development and Construction in Progress		0
Total		2,920
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | Kendall Center Master Plan (formerly Cambridge Master Plan)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Property Name		Kendall Center Master Plan (formerly Cambridge Master Plan)
Type		Land
Location		Cambridge, MA
Encumbrances		$ 0
Original Land		0
Original Building		0
Costs Capitalized Subsequent to Acquisition		1,403
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		1,403
Development and Construction in Progress		0
Total		1,403
Accumulated Depreciation		$ 0
Year(s) built / renovated		N/A
Depreciable Lives (Years)		N/A
Boston Properties Limited Partnership [Member] | 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		1,213
Land and improvements		0
Buildings and Improvements		0
Land Held for Development		1,213
Development and Construction in Progress		0
Total		1,213
Accumulated Depreciation		$ 0
Year(s) built / renovated		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 [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 totaling approximately $80.2 million.

[2] Depreciation of the buildings and improvements are calculated over lives ranging from the life of the lease to 40 years.

[3] Includes the unamortized balance of the historical fair value adjustment totaling approximately $80.2 million.

[4] Depreciation of the buildings and improvements are calculated over lives ranging from the life of the lease to 40 years.