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Real Estate and Accumulated Depreciation Schedule of Real Estate and Accumulated Depreciation (BPLP) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2019
Jan. 01, 2019
Dec. 31, 2018
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Encumbrances [1] $ 2,922,408    
Original Land 5,024,060    
Original Building 13,057,336    
Costs Capitalized Subsequent to Acquisition 4,763,301    
Land and improvements [2] 5,474,337    
Buildings and Improvements [3] 16,325,796    
Land Held for Development [4] 254,828    
Development and Construction in Progress 789,736    
Total 22,844,697    
Accumulated Depreciation 5,239,179    
Furniture, Fixtures and Equipment 44,313   $ 44,351
Real Estate Aggregate Accumulated Depreciation For Tax Purposes $ 4,000,000    
Real Estate and Accumulated Depreciation, Life Used for Depreciation 40 years    
Unamortized deferred finance costs $ (26,700)    
Right-of-use assets - finance leases 237,394    
Right of use assets - operating leases $ 148,640 $ 151,800  
767 Fifth Avenue (the General Motors Building)      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 767 Fifth Avenue (the General Motors Building)    
Type Office    
Location New York, NY    
Encumbrances $ 2,274,028    
Original Land 1,796,252    
Original Building 1,532,654    
Costs Capitalized Subsequent to Acquisition 202,612    
Land and improvements 1,796,252    
Buildings and Improvements 1,735,266    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 3,531,518    
Accumulated Depreciation $ 313,158    
Year(s) Built / Renovated 1968/2019    
Year(s) Acquired 2013    
Depreciable Lives (Years) [5] (1)    
Prudential Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Prudential Center    
Type Office    
Location Boston, MA    
Encumbrances $ 0    
Original Land 92,077    
Original Building 948,357    
Costs Capitalized Subsequent to Acquisition 556,458    
Land and improvements 115,638    
Buildings and Improvements 1,478,578    
Land Held for Development 2,676    
Development and Construction in Progress 0    
Total 1,596,892    
Accumulated Depreciation $ 596,740    
Year(s) Built / Renovated 1965/1993/2002/2016-2017    
Year(s) Acquired 1998/1999/2000    
Depreciable Lives (Years) [5] (1)    
Embarcadero Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Embarcadero Center    
Type Office    
Location San Francisco, CA    
Encumbrances $ 0    
Original Land 179,697    
Original Building 847,410    
Costs Capitalized Subsequent to Acquisition 415,228    
Land and improvements 195,987    
Buildings and Improvements 1,246,348    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 1,442,335    
Accumulated Depreciation $ 633,711    
Year(s) Built / Renovated 1970/1989    
Year(s) Acquired 1998-1999    
Depreciable Lives (Years) [5] (1)    
399 Park Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 300,519    
Land and improvements 354,107    
Buildings and Improvements 985,970    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 1,340,077    
Accumulated Depreciation $ 358,960    
Year(s) Built / Renovated 1961/2018    
Year(s) Acquired 2002    
Depreciable Lives (Years) [5] (1)    
601 Lexington Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 601 Lexington Avenue    
Type Office    
Location New York, NY    
Encumbrances $ 644,778    
Original Land 241,600    
Original Building 494,782    
Costs Capitalized Subsequent to Acquisition 454,902    
Land and improvements 289,639    
Buildings and Improvements 688,550    
Land Held for Development 0    
Development and Construction in Progress 213,095    
Total 1,191,284    
Accumulated Depreciation $ 289,482    
Year(s) Built / Renovated 1977/1997    
Year(s) Acquired 2001    
Depreciable Lives (Years) [5] (1)    
Salesforce Tower      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Salesforce Tower    
Type Office    
Location San Francisco, CA    
Encumbrances $ 0    
Original Land 200,349    
Original Building 946,205    
Costs Capitalized Subsequent to Acquisition 0    
Land and improvements 200,349    
Buildings and Improvements 946,205    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 1,146,554    
Accumulated Depreciation $ 38,727    
Year(s) Built / Renovated 2018    
Year(s) Acquired 2013    
Depreciable Lives (Years) [5] (1)    
200 Clarendon Street and Garage      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 200 Clarendon Street and Garage    
Type Office    
Location Boston, MA    
Encumbrances $ 0    
Original Land 219,543    
Original Building 667,884    
Costs Capitalized Subsequent to Acquisition 210,160    
Land and improvements 250,134    
Buildings and Improvements 829,529    
Land Held for Development 17,924    
Development and Construction in Progress 0    
Total 1,097,587    
Accumulated Depreciation $ 214,533    
Year(s) Built / Renovated 1976    
Year(s) Acquired 2010    
Depreciable Lives (Years) [5] (1)    
250 West 55th Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 51,928    
Land and improvements 285,263    
Buildings and Improvements 655,095    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 940,358    
Accumulated Depreciation $ 116,857    
Year(s) Built / Renovated 2014    
Year(s) Acquired 2007    
Depreciable Lives (Years) [5] (1)    
100 Federal Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 102,984    
Land and improvements 131,067    
Buildings and Improvements 538,938    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 670,005    
Accumulated Depreciation $ 122,799    
Year(s) Built / Renovated 1971-1975/2017    
Year(s) Acquired 2012    
Depreciable Lives (Years) [5] (1)    
Times Square Tower      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 113,222    
Land and improvements 169,193    
Buildings and Improvements 489,880    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 659,073    
Accumulated Depreciation $ 217,303    
Year(s) Built / Renovated 2004    
Year(s) Acquired 2000    
Depreciable Lives (Years) [5] (1)    
Carnegie Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Carnegie Center    
Type Office    
Location Princeton, NJ    
Encumbrances $ 0    
Original Land 142,666    
Original Building 316,856    
Costs Capitalized Subsequent to Acquisition 152,280    
Land and improvements 94,240    
Buildings and Improvements 462,882    
Land Held for Development 54,680    
Development and Construction in Progress 0    
Total 611,802    
Accumulated Depreciation $ 208,331    
Year(s) Built / Renovated 1983-2016    
Year(s) Acquired 1998/1999/2000/2007/2014/2017/2019    
Depreciable Lives (Years) [5] (1)    
Atlantic Wharf      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 18,709    
Land and improvements 63,988    
Buildings and Improvements 473,246    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 537,234    
Accumulated Depreciation $ 131,828    
Year(s) Built / Renovated 2011    
Year(s) Acquired 2007    
Depreciable Lives (Years) [5] (1)    
510 Madison Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 25,495    
Land and improvements 103,000    
Buildings and Improvements 279,160    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 382,160    
Accumulated Depreciation $ 72,213    
Year(s) Built / Renovated 2012    
Year(s) Acquired 2010    
Depreciable Lives (Years) [5] (1)    
Fountain Square      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Fountain Square    
Type Office    
Location Reston, VA    
Encumbrances $ 0    
Original Land 56,853    
Original Building 306,298    
Costs Capitalized Subsequent to Acquisition 12,140    
Land and improvements 56,853    
Buildings and Improvements 318,438    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 375,291    
Accumulated Depreciation $ 78,498    
Year(s) Built / Renovated 1986-1990    
Year(s) Acquired 2012    
Depreciable Lives (Years) [5] (1)    
599 Lexington Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 599 Lexington Avenue    
Type Office    
Location New York, NY    
Encumbrances $ 0    
Original Land 81,040    
Original Building 100,507    
Costs Capitalized Subsequent to Acquisition 188,572    
Land and improvements 87,852    
Buildings and Improvements 282,267    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 370,119    
Accumulated Depreciation $ 183,291    
Year(s) Built / Renovated 1986    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
680 Folsom Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 7,907    
Land and improvements 72,545    
Buildings and Improvements 227,673    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 300,218    
Accumulated Depreciation $ 46,777    
Year(s) Built / Renovated 2014    
Year(s) Acquired 2012    
Depreciable Lives (Years) [5] (1)    
2200 Pennsylvania Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 113,627    
Land and improvements 109,038    
Buildings and Improvements 188,130    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 297,168    
Accumulated Depreciation $ 59,190    
Year(s) Built / Renovated 2011    
Year(s) Acquired 2008    
Depreciable Lives (Years) [5] (1)    
145 Broadway      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 145 Broadway    
Type Office    
Location Cambridge, MA    
Encumbrances $ 0    
Original Land 121    
Original Building 273,013    
Costs Capitalized Subsequent to Acquisition 23,246    
Land and improvements 23,367    
Buildings and Improvements 273,013    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 296,380    
Accumulated Depreciation $ 1,511    
Year(s) Built / Renovated 2019    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
South of Market and Democracy Tower      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 26,415    
Land and improvements 13,687    
Buildings and Improvements 263,810    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 277,497    
Accumulated Depreciation $ 99,478    
Year(s) Built / Renovated 2008-2009    
Year(s) Acquired 2003    
Depreciable Lives (Years) [5] (1)    
601 Massachusetts Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 601 Massachusetts Avenue    
Type Office    
Location Washington, DC    
Encumbrances $ 0    
Original Land 95,310    
Original Building 165,173    
Costs Capitalized Subsequent to Acquisition 3,945    
Land and improvements 95,322    
Buildings and Improvements 169,106    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 264,428    
Accumulated Depreciation $ 24,502    
Year(s) Built / Renovated 2016    
Year(s) Acquired 2008    
Depreciable Lives (Years) [5] (1)    
Bay Colony Corporate Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 80,077    
Land and improvements 18,789    
Buildings and Improvements 228,528    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 247,317    
Accumulated Depreciation $ 79,824    
Year(s) Built / Renovated 1985-1989    
Year(s) Acquired 2011    
Depreciable Lives (Years) [5] (1)    
Gateway Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 61,791    
Land and improvements 30,627    
Buildings and Improvements 198,664    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 229,291    
Accumulated Depreciation $ 106,680    
Year(s) Built / Renovated 1984/1986/2002    
Year(s) Acquired 1999    
Depreciable Lives (Years) [5] (1)    
535 Mission Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 3,276    
Land and improvements 40,933    
Buildings and Improvements 151,654    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 192,587    
Accumulated Depreciation $ 26,293    
Year(s) Built / Renovated 2015    
Year(s) Acquired 2013    
Depreciable Lives (Years) [5] (1)    
Mountain View Research Park      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 12,704    
Land and improvements 95,066    
Buildings and Improvements 81,077    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 176,143    
Accumulated Depreciation $ 19,807    
Year(s) Built / Renovated 1977-1981/2007-2013    
Year(s) Acquired 2013    
Depreciable Lives (Years) [5] (1)    
Reservoir Place      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Reservoir Place    
Type Office    
Location Waltham, MA    
Encumbrances $ 0    
Original Land 18,605    
Original Building 104,124    
Costs Capitalized Subsequent to Acquisition 53,718    
Land and improvements 20,108    
Buildings and Improvements 156,339    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 176,447    
Accumulated Depreciation $ 70,870    
Year(s) Built / Renovated 1955/1987/2017    
Year(s) Acquired 1997/1998    
Depreciable Lives (Years) [5] (1)    
1330 Connecticut Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 36,847    
Land and improvements 27,135    
Buildings and Improvements 118,005    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 145,140    
Accumulated Depreciation $ 32,775    
Year(s) Built / Renovated 1984/2018    
Year(s) Acquired 2004    
Depreciable Lives (Years) [5] (1)    
Kingstowne Towne Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 3,376    
Land and improvements 18,062    
Buildings and Improvements 112,373    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 130,435    
Accumulated Depreciation $ 44,294    
Year(s) Built / Renovated 2003-2006    
Year(s) Acquired 2007    
Depreciable Lives (Years) [5] (1)    
One Freedom Square      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 34,372    
Land and improvements 11,293    
Buildings and Improvements 117,512    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 128,805    
Accumulated Depreciation $ 59,006    
Year(s) Built / Renovated 2000    
Year(s) Acquired 2003    
Depreciable Lives (Years) [5] (1)    
Weston Corporate Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 $ 29,227    
Year(s) Built / Renovated 2010    
Year(s) Acquired 2001    
Depreciable Lives (Years) [5] (1)    
Capital Gallery      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 88,704    
Land and improvements 8,662    
Buildings and Improvements 114,332    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 122,994    
Accumulated Depreciation $ 71,631    
Year(s) Built / Renovated 1981/2006    
Year(s) Acquired 2007    
Depreciable Lives (Years) [5] (1)    
Two Freedom Square      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 23,209    
Land and improvements 15,420    
Buildings and Improvements 99,458    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 114,878    
Accumulated Depreciation $ 50,668    
Year(s) Built / Renovated 2001    
Year(s) Acquired 2003    
Depreciable Lives (Years) [5] (1)    
One and Two Reston Overlook      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name One and Two Reston Overlook    
Type Office    
Location Reston, VA    
Encumbrances $ 0    
Original Land 16,456    
Original Building 66,192    
Costs Capitalized Subsequent to Acquisition 24,181    
Land and improvements 16,179    
Buildings and Improvements 90,650    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 106,829    
Accumulated Depreciation $ 51,503    
Year(s) Built / Renovated 1999    
Year(s) Acquired 2000    
Depreciable Lives (Years) [5] (1)    
355 Main Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 355 Main Street    
Type Office    
Location Cambridge, MA    
Encumbrances $ 0    
Original Land 18,863    
Original Building 53,346    
Costs Capitalized Subsequent to Acquisition 27,582    
Land and improvements 21,173    
Buildings and Improvements 78,618    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 99,791    
Accumulated Depreciation $ 26,439    
Year(s) Built / Renovated 1981/1996/2013    
Year(s) Acquired 2006    
Depreciable Lives (Years) [5] (1)    
140 Kendrick Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 17,574    
Land and improvements 19,092    
Buildings and Improvements 83,482    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 102,574    
Accumulated Depreciation $ 35,721    
Year(s) Built / Renovated 2000    
Year(s) Acquired 2004    
Depreciable Lives (Years) [5] (1)    
Discovery Square      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 20,905    
Land and improvements 12,533    
Buildings and Improvements 91,352    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 103,885    
Accumulated Depreciation $ 43,619    
Year(s) Built / Renovated 2001    
Year(s) Acquired 2003    
Depreciable Lives (Years) [5] (1)    
880 & 890 Winter Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 880 & 890 Winter Street    
Type Office    
Location Waltham, MA    
Encumbrances $ 0    
Original Land 29,510    
Original Building 65,812    
Costs Capitalized Subsequent to Acquisition 0    
Land and improvements 29,510    
Buildings and Improvements 65,812    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 95,322    
Accumulated Depreciation $ 1,458    
Year(s) Built / Renovated 1998-1999    
Year(s) Acquired 2019    
Depreciable Lives (Years) [5] (1)    
10 CityPoint      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 10 CityPoint    
Type Office    
Location Waltham, MA    
Encumbrances $ 0    
Original Land 1,953    
Original Building 85,752    
Costs Capitalized Subsequent to Acquisition 4,697    
Land and improvements 2,290    
Buildings and Improvements 90,112    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 92,402    
Accumulated Depreciation $ 10,928    
Year(s) Built / Renovated 2016    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
90 Broadway      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 19,857    
Land and improvements 20,785    
Buildings and Improvements 70,254    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 91,039    
Accumulated Depreciation $ 23,621    
Year(s) Built / Renovated 1983/1998/2013    
Year(s) Acquired 2006    
Depreciable Lives (Years) [5] (1)    
77 CityPoint      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 10,556    
Land and improvements 14,023    
Buildings and Improvements 70,763    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 84,786    
Accumulated Depreciation $ 27,172    
Year(s) Built / Renovated 2008    
Year(s) Acquired 2001    
Depreciable Lives (Years) [5] (1)    
230 CityPoint      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 22,057    
Land and improvements 13,807    
Buildings and Improvements 71,262    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 85,069    
Accumulated Depreciation $ 29,255    
Year(s) Built / Renovated 1992    
Year(s) Acquired 2005    
Depreciable Lives (Years) [5] (1)    
Waltham Weston Corporate Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 13,165    
Land and improvements 11,097    
Buildings and Improvements 73,147    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 84,244    
Accumulated Depreciation $ 35,567    
Year(s) Built / Renovated 2003    
Year(s) Acquired 1999    
Depreciable Lives (Years) [5] (1)    
3625-3635 Peterson Way      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 3625-3635 Peterson Way    
Type Office    
Location Santa Clara, CA    
Encumbrances $ 0    
Original Land 63,206    
Original Building 14,879    
Costs Capitalized Subsequent to Acquisition 752    
Land and improvements 63,206    
Buildings and Improvements 14,879    
Land Held for Development 752    
Development and Construction in Progress 0    
Total 78,837    
Accumulated Depreciation $ 11,172    
Year(s) Built / Renovated 1979    
Year(s) Acquired 2016    
Depreciable Lives (Years) [5] (1)    
2440 West El Camino Real      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 5,454    
Land and improvements 16,741    
Buildings and Improvements 56,739    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 73,480    
Accumulated Depreciation $ 13,090    
Year(s) Built / Renovated 1987/2003    
Year(s) Acquired 2011    
Depreciable Lives (Years) [5] (1)    
191 Spring Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 59,751    
Costs Capitalized Subsequent to Acquisition 7,695    
Land and improvements 3,151    
Buildings and Improvements 67,145    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 70,296    
Accumulated Depreciation $ 21,917    
Year(s) Built / Renovated 1971/1995/2018    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
300 Binney Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 $ 11,146    
Year(s) Built / Renovated 2013    
Year(s) Acquired 2009    
Depreciable Lives (Years) [5] (1)    
Wisconsin Place      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 14,924    
Land and improvements 0    
Buildings and Improvements 68,273    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 68,273    
Accumulated Depreciation $ 25,934    
Year(s) Built / Renovated 2009    
Year(s) Acquired 2004    
Depreciable Lives (Years) [5] (1)    
Reston Corporate Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 6,236    
Land and improvements 10,148    
Buildings and Improvements 56,080    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 66,228    
Accumulated Depreciation $ 29,860    
Year(s) Built / Renovated 1984    
Year(s) Acquired 1998    
Depreciable Lives (Years) [5] (1)    
New Dominion Technology Park, Bldg. Two      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name New Dominion Technology Park, Bldg. Two    
Type Office    
Location Herndon, VA    
Encumbrances $ 0    
Original Land 5,584    
Original Building 51,868    
Costs Capitalized Subsequent to Acquisition 4,157    
Land and improvements 6,510    
Buildings and Improvements 55,099    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 61,609    
Accumulated Depreciation $ 26,894    
Year(s) Built / Renovated 2004    
Year(s) Acquired 1998    
Depreciable Lives (Years) [5] (1)    
255 Main Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 34,124    
Land and improvements 548    
Buildings and Improvements 58,820    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 59,368    
Accumulated Depreciation $ 33,543    
Year(s) Built / Renovated 1987    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
University Place      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name University Place    
Type Office    
Location Cambridge, MA    
Encumbrances $ 3,602    
Original Land 0    
Original Building 37,091    
Costs Capitalized Subsequent to Acquisition 16,001    
Land and improvements 7,418    
Buildings and Improvements 45,674    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 53,092    
Accumulated Depreciation $ 29,423    
Year(s) Built / Renovated 1985    
Year(s) Acquired 1998    
Depreciable Lives (Years) [5] (1)    
Sumner Square      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 21,344    
Land and improvements 3,535    
Buildings and Improvements 47,178    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 50,713    
Accumulated Depreciation $ 27,093    
Year(s) Built / Renovated 1985    
Year(s) Acquired 1999    
Depreciable Lives (Years) [5] (1)    
New Dominion Technology Park, Bldg. One      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name New Dominion Technology Park, Bldg. One    
Type Office    
Location Herndon, VA    
Encumbrances $ 0    
Original Land 3,880    
Original Building 43,227    
Costs Capitalized Subsequent to Acquisition 3,927    
Land and improvements 4,583    
Buildings and Improvements 46,451    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 51,034    
Accumulated Depreciation $ 29,141    
Year(s) Built / Renovated 2001    
Year(s) Acquired 1998    
Depreciable Lives (Years) [5] (1)    
200 West Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 8,211    
Land and improvements 16,813    
Buildings and Improvements 30,425    
Land Held for Development 0    
Development and Construction in Progress 2,104    
Total 49,342    
Accumulated Depreciation $ 17,001    
Year(s) Built / Renovated 1999    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
North First Business Park      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name North First Business Park    
Type Office    
Location San Jose, CA    
Encumbrances $ 0    
Original Land 23,398    
Original Building 13,069    
Costs Capitalized Subsequent to Acquisition 4,571    
Land and improvements 23,377    
Buildings and Improvements 17,661    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 41,038    
Accumulated Depreciation $ 16,411    
Year(s) Built / Renovated 1981    
Year(s) Acquired 2007    
Depreciable Lives (Years) [5] (1)    
150 Broadway      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 8,540    
Land and improvements 1,323    
Buildings and Improvements 33,109    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 34,432    
Accumulated Depreciation $ 19,875    
Year(s) Built / Renovated 1999    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
105 Broadway      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 11,406    
Land and improvements 2,395    
Buildings and Improvements 23,253    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 25,648    
Accumulated Depreciation $ 11,870    
Year(s) Built / Renovated 1990    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
Lexington Office Park      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 18,547    
Land and improvements 1,264    
Buildings and Improvements 19,707    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 20,971    
Accumulated Depreciation $ 14,312    
Year(s) Built / Renovated 1982    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
201 Spring Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 1,172    
Land and improvements 3,124    
Buildings and Improvements 16,200    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 19,324    
Accumulated Depreciation $ 8,587    
Year(s) Built / Renovated 1997    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
The Point      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name The Point    
Type Office    
Location Waltham, MA    
Encumbrances $ 0    
Original Land 6,395    
Original Building 10,040    
Costs Capitalized Subsequent to Acquisition 421    
Land and improvements 6,492    
Buildings and Improvements 10,364    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 16,856    
Accumulated Depreciation $ 1,349    
Year(s) Built / Renovated 2015    
Year(s) Acquired 2007    
Depreciable Lives (Years) [5] (1)    
33 Hayden Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 12,898    
Land and improvements 425    
Buildings and Improvements 15,973    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 16,398    
Accumulated Depreciation $ 5,678    
Year(s) Built / Renovated 1979    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
690 Folsom Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 690 Folsom Street    
Type Office    
Location San Francisco, CA    
Encumbrances $ 0    
Original Land 3,219    
Original Building 11,038    
Costs Capitalized Subsequent to Acquisition 1,157    
Land and improvements 3,219    
Buildings and Improvements 12,195    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 15,414    
Accumulated Depreciation $ 2,284    
Year(s) Built / Renovated 2015    
Year(s) Acquired 2012    
Depreciable Lives (Years) [5] (1)    
92-100 Hayden Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 7,529    
Land and improvements 802    
Buildings and Improvements 14,069    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 14,871    
Accumulated Depreciation $ 12,041    
Year(s) Built / Renovated 1985    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
181 Spring Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 181 Spring Street    
Type Office    
Location Lexington, MA    
Encumbrances $ 0    
Original Land 1,066    
Original Building 9,520    
Costs Capitalized Subsequent to Acquisition 2,177    
Land and improvements 1,160    
Buildings and Improvements 11,603    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 12,763    
Accumulated Depreciation $ 5,597    
Year(s) Built / Renovated 1999    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
195 West Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 4,218    
Land and improvements 1,858    
Buildings and Improvements 10,623    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 12,481    
Accumulated Depreciation $ 8,352    
Year(s) Built / Renovated 1990    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
7501 Boston Boulevard, Building Seven      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 816    
Land and improvements 791    
Buildings and Improvements 9,963    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 10,754    
Accumulated Depreciation $ 5,393    
Year(s) Built / Renovated 1997    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
7435 Boston Boulevard, Building One      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 4,983    
Land and improvements 659    
Buildings and Improvements 8,538    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 9,197    
Accumulated Depreciation $ 6,344    
Year(s) Built / Renovated 1982    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
7450 Boston Boulevard, Building Three      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 2,591    
Land and improvements 1,430    
Buildings and Improvements 7,007    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 8,437    
Accumulated Depreciation $ 3,575    
Year(s) Built / Renovated 1987    
Year(s) Acquired 1998    
Depreciable Lives (Years) [5] (1)    
32 Hartwell Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 6,115    
Land and improvements 314    
Buildings and Improvements 7,912    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 8,226    
Accumulated Depreciation $ 1,975    
Year(s) Built / Renovated 1968/1979/1987    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
250 Binney Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 $ 5,829    
Year(s) Built / Renovated 1983    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
8000 Grainger Court, Building Five      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 3,198    
Land and improvements 601    
Buildings and Improvements 7,245    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 7,846    
Accumulated Depreciation $ 5,752    
Year(s) Built / Renovated 1984    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
453 Ravendale Drive      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 676    
Land and improvements 5,477    
Buildings and Improvements 1,766    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 7,243    
Accumulated Depreciation $ 690    
Year(s) Built / Renovated 1977    
Year(s) Acquired 2012    
Depreciable Lives (Years) [5] (1)    
7300 Boston Boulevard, Building Thirteen      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 1,007    
Land and improvements 661    
Buildings and Improvements 5,727    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 6,388    
Accumulated Depreciation $ 1,984    
Year(s) Built / Renovated 2002    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
17 Hartwell Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 17 Hartwell Avenue    
Type Office    
Location Lexington, MA    
Encumbrances $ 0    
Original Land 26    
Original Building 150    
Costs Capitalized Subsequent to Acquisition 6,064    
Land and improvements 65    
Buildings and Improvements 6,175    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 6,240    
Accumulated Depreciation $ 1,966    
Year(s) Built / Renovated 1968    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
7601 Boston Boulevard, Building Eight      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 7601 Boston Boulevard, Building Eight    
Type Office    
Location Springfield, VA    
Encumbrances $ 0    
Original Land 200    
Original Building 878    
Costs Capitalized Subsequent to Acquisition 5,060    
Land and improvements 551    
Buildings and Improvements 5,587    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 6,138    
Accumulated Depreciation $ 4,689    
Year(s) Built / Renovated 1986    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
7500 Boston Boulevard, Building Six      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 7500 Boston Boulevard, Building Six    
Type Office    
Location Springfield, VA    
Encumbrances $ 0    
Original Land 138    
Original Building 3,749    
Costs Capitalized Subsequent to Acquisition 1,640    
Land and improvements 367    
Buildings and Improvements 5,160    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 5,527    
Accumulated Depreciation $ 4,237    
Year(s) Built / Renovated 1985    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
8000 Corporate Court, Building Eleven      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 1,596    
Land and improvements 774    
Buildings and Improvements 4,029    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 4,803    
Accumulated Depreciation $ 3,191    
Year(s) Built / Renovated 1989    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
7375 Boston Boulevard, Building Ten      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 1,032    
Land and improvements 93    
Buildings and Improvements 3,647    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 3,740    
Accumulated Depreciation $ 2,606    
Year(s) Built / Renovated 1988    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
7374 Boston Boulevard, Building Four      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 1,828    
Land and improvements 398    
Buildings and Improvements 3,276    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 3,674    
Accumulated Depreciation $ 2,779    
Year(s) Built / Renovated 1984    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
7451 Boston Boulevard, Building Two      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 1,667    
Land and improvements 613    
Buildings and Improvements 2,845    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 3,458    
Accumulated Depreciation $ 2,610    
Year(s) Built / Renovated 1982    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
Signature at Reston      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Signature at Reston    
Type Residential    
Location Reston, VA    
Encumbrances $ 0    
Original Land 27,076    
Original Building 190,580    
Costs Capitalized Subsequent to Acquisition 393    
Land and improvements 27,076    
Buildings and Improvements 190,973    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 218,049    
Accumulated Depreciation $ 8,773    
Year(s) Built / Renovated 2018    
Year(s) Acquired 2013    
Depreciable Lives (Years) [5] (1)    
Proto Kendall Square      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Proto Kendall Square    
Type Residential    
Location Cambridge, MA    
Encumbrances $ 0    
Original Land 9,243    
Original Building 127,248    
Costs Capitalized Subsequent to Acquisition 2,939    
Land and improvements 9,245    
Buildings and Improvements 130,185    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 139,430    
Accumulated Depreciation $ 4,566    
Year(s) Built / Renovated 2018    
Year(s) Acquired 2015    
Depreciable Lives (Years) [5] (1)    
The Avant at Reston Town Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 830    
Land and improvements 20,350    
Buildings and Improvements 92,825    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 113,175    
Accumulated Depreciation $ 14,728    
Year(s) Built / Renovated 2014    
Year(s) Acquired 2010    
Depreciable Lives (Years) [5] (1)    
The Lofts at Atlantic Wharf      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 1,897    
Land and improvements 3,529    
Buildings and Improvements 56,788    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 60,317    
Accumulated Depreciation $ 12,639    
Year(s) Built / Renovated 2011    
Year(s) Acquired 2007    
Depreciable Lives (Years) [5] (1)    
Boston Marriott Cambridge      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 35,813    
Land and improvements 1,201    
Buildings and Improvements 73,008    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 74,209    
Accumulated Depreciation $ 46,605    
Year(s) Built / Renovated 1986/2017    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
Kendall Center Green Garage      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Kendall Center Green Garage    
Type Garage    
Location Cambridge, MA    
Encumbrances $ 0    
Original Land 0    
Original Building 35,035    
Costs Capitalized Subsequent to Acquisition 7,329    
Land and improvements 103    
Buildings and Improvements 42,261    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 42,364    
Accumulated Depreciation $ 13,512    
Year(s) Built / Renovated 1984    
Year(s) Acquired 2006    
Depreciable Lives (Years) [5] (1)    
Kendall Center Yellow Garage      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Kendall Center Yellow Garage    
Type Garage    
Location Cambridge, MA    
Encumbrances $ 0    
Original Land 1,256    
Original Building 15,697    
Costs Capitalized Subsequent to Acquisition 1,552    
Land and improvements 1,434    
Buildings and Improvements 17,071    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 18,505    
Accumulated Depreciation $ 6,031    
Year(s) Built / Renovated 2006    
Year(s) Acquired 2004    
Depreciable Lives (Years) [5] (1)    
Kendall Center Blue Garage      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Kendall Center Blue Garage    
Type Garage    
Location Cambridge, MA    
Encumbrances $ 0    
Original Land 1,163    
Original Building 11,633    
Costs Capitalized Subsequent to Acquisition 2,151    
Land and improvements 1,579    
Buildings and Improvements 13,368    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 14,947    
Accumulated Depreciation $ 9,728    
Year(s) Built / Renovated 1990    
Year(s) Acquired 1997    
Depreciable Lives (Years) [5] (1)    
The Skylyne (MacArthur Station Residences)      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name The Skylyne (MacArthur Station Residences)    
Type Development    
Location Oakland, CA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 226,526    
Land and improvements 29,807    
Buildings and Improvements 0    
Land Held for Development 0    
Development and Construction in Progress 196,719    
Total 226,526    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired N/A    
Depreciable Lives (Years) N/A    
2100 Pennsylvania Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 2100 Pennsylvania Avenue    
Type Development    
Location Washington, DC    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 224,380    
Land and improvements 185,129    
Buildings and Improvements 0    
Land Held for Development 0    
Development and Construction in Progress 39,251    
Total 224,380    
Accumulated Depreciation $ 1,024    
Year(s) Built / Renovated N/A    
Year(s) Acquired N/A    
Depreciable Lives (Years) N/A    
Reston Gateway      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Reston Gateway    
Type Development    
Location Reston, VA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 150,632    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 0    
Development and Construction in Progress 150,632    
Total 150,632    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 1998    
Depreciable Lives (Years) N/A    
17Fifty Presidents Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 17Fifty Presidents Street    
Type Development    
Location Reston, VA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 99,816    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 0    
Development and Construction in Progress 99,816    
Total 99,816    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2013    
Depreciable Lives (Years) N/A    
20 CityPoint      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 20 CityPoint    
Type Development    
Location Waltham, MA    
Encumbrances $ 0    
Original Land 4,721    
Original Building 52,039    
Costs Capitalized Subsequent to Acquisition 20,007    
Land and improvements 4,721    
Buildings and Improvements 52,039    
Land Held for Development 0    
Development and Construction in Progress 20,007    
Total 76,767    
Accumulated Depreciation $ 1,136    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2007    
Depreciable Lives (Years) N/A    
325 Main Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 325 Main Street    
Type Development    
Location Cambridge, MA    
Encumbrances $ 0    
Original Land 174    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 68,903    
Land and improvements 965    
Buildings and Improvements 0    
Land Held for Development 0    
Development and Construction in Progress 68,112    
Total 69,077    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 1997    
Depreciable Lives (Years) N/A    
North First Master Plan      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name North First Master Plan    
Type Land    
Location San Jose, CA    
Encumbrances $ 0    
Original Land 35,004    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 3,932    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 38,936    
Development and Construction in Progress 0    
Total 38,936    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2007    
Depreciable Lives (Years) N/A    
Plaza at Almaden      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 34,889    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 34,889    
Development and Construction in Progress 0    
Total 34,889    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2006    
Depreciable Lives (Years) N/A    
4th and Harrison      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 425 Fourth Street    
Type Land    
Location San Francisco, CA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 22,074    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 22,074    
Development and Construction in Progress 0    
Total 22,074    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired N/A    
Depreciable Lives (Years) N/A    
Springfield Metro Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 19,844    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 19,844    
Development and Construction in Progress 0    
Total 19,844    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2007    
Depreciable Lives (Years) N/A    
Reston Gateway Master Plan      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Reston Gateway Master Plan    
Type Land    
Location Reston, VA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 18,292    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 18,292    
Development and Construction in Progress 0    
Total 18,292    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 1998    
Depreciable Lives (Years) N/A    
214 Third Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 17,692    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 17,692    
Development and Construction in Progress 0    
Total 17,692    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2006    
Depreciable Lives (Years) N/A    
103 Fourth Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 103 Fourth Avenue    
Type Land    
Location Waltham, MA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 12,826    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 12,826    
Development and Construction in Progress 0    
Total 12,826    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2007    
Depreciable Lives (Years) N/A    
Crane Meadow      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 8,866    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 8,866    
Development and Construction in Progress 0    
Total 8,866    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2000    
Depreciable Lives (Years) N/A    
Broad Run Business Park      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Broad Run Business Park    
Type Land    
Location Loudoun County, VA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 2,396    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 2,396    
Development and Construction in Progress 0    
Total 2,396    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 1998    
Depreciable Lives (Years) N/A    
Kendall Center Master Plan      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Kendall Center Master Plan    
Type Land    
Location Cambridge, MA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 1,693    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 1,693    
Development and Construction in Progress 0    
Total 1,693    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 1997    
Depreciable Lives (Years) N/A    
Weston Quarry      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Weston Quarry    
Type Land    
Location Weston, MA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 1,249    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 1,249    
Development and Construction in Progress 0    
Total 1,249    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2001    
Depreciable Lives (Years) N/A    
Reston Overlook Master Plan      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Reston Overlook Master Plan    
Type Land    
Location Reston, VA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 39    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 39    
Development and Construction in Progress 0    
Total 39    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2000    
Depreciable Lives (Years) N/A    
Boston Properties Limited Partnership      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Encumbrances [6] $ 2,922,408    
Original Land 5,024,060    
Original Building 13,057,336    
Costs Capitalized Subsequent to Acquisition 4,368,080    
Land and improvements [7] 5,373,884    
Buildings and Improvements [8] 16,031,028    
Land Held for Development [9] 254,828    
Development and Construction in Progress 789,736    
Total 22,449,476    
Accumulated Depreciation 5,135,289    
Furniture, Fixtures and Equipment 44,313   $ 44,351
Real Estate Aggregate Cost For Tax Purposes 20,700,000    
Real Estate Aggregate Accumulated Depreciation For Tax Purposes $ 4,500,000    
Real Estate and Accumulated Depreciation, Life Used for Depreciation 40 years    
Unamortized deferred finance costs $ (26,700)    
Right-of-use assets - finance leases 237,394    
Right of use assets - operating leases $ 148,640    
Boston Properties Limited Partnership | 767 Fifth Avenue (the General Motors Building)      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 767 Fifth Avenue (the General Motors Building)    
Type Office    
Location New York, NY    
Encumbrances $ 2,274,028    
Original Land 1,796,252    
Original Building 1,532,654    
Costs Capitalized Subsequent to Acquisition 202,612    
Land and improvements 1,796,252    
Buildings and Improvements 1,735,266    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 3,531,518    
Accumulated Depreciation $ 313,158    
Year(s) Built / Renovated 1968/2019    
Year(s) Acquired 2013    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Prudential Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Prudential Center    
Type Office    
Location Boston, MA    
Encumbrances $ 0    
Original Land 92,077    
Original Building 948,357    
Costs Capitalized Subsequent to Acquisition 496,088    
Land and improvements 100,540    
Buildings and Improvements 1,433,306    
Land Held for Development 2,676    
Development and Construction in Progress 0    
Total 1,536,522    
Accumulated Depreciation $ 580,797    
Year(s) Built / Renovated 1965/1993/2002/2016-2017    
Year(s) Acquired 1998/1999/2000    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Embarcadero Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Embarcadero Center    
Type Office    
Location San Francisco, CA    
Encumbrances $ 0    
Original Land 179,697    
Original Building 847,410    
Costs Capitalized Subsequent to Acquisition 352,847    
Land and improvements 180,420    
Buildings and Improvements 1,199,534    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 1,379,954    
Accumulated Depreciation $ 617,163    
Year(s) Built / Renovated 1970/1989    
Year(s) Acquired 1998-1999    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 399 Park Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 240,911    
Land and improvements 339,200    
Buildings and Improvements 941,269    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 1,280,469    
Accumulated Depreciation $ 343,191    
Year(s) Built / Renovated 1961/2018    
Year(s) Acquired 2002    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 601 Lexington Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 601 Lexington Avenue    
Type Office    
Location New York, NY    
Encumbrances $ 644,778    
Original Land 241,600    
Original Building 494,782    
Costs Capitalized Subsequent to Acquisition 417,816    
Land and improvements 279,281    
Buildings and Improvements 661,822    
Land Held for Development 0    
Development and Construction in Progress 213,095    
Total 1,154,198    
Accumulated Depreciation $ 280,028    
Year(s) Built / Renovated 1977/1997    
Year(s) Acquired 2001    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Salesforce Tower      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Salesforce Tower    
Type Office    
Location San Francisco, CA    
Encumbrances $ 0    
Original Land 200,349    
Original Building 946,205    
Costs Capitalized Subsequent to Acquisition 0    
Land and improvements 200,349    
Buildings and Improvements 946,205    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 1,146,554    
Accumulated Depreciation $ 38,727    
Year(s) Built / Renovated 2018    
Year(s) Acquired 2013    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 200 Clarendon Street and Garage      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 200 Clarendon Street and Garage    
Type Office    
Location Boston, MA    
Encumbrances $ 0    
Original Land 219,543    
Original Building 667,884    
Costs Capitalized Subsequent to Acquisition 210,160    
Land and improvements 250,134    
Buildings and Improvements 829,529    
Land Held for Development 17,924    
Development and Construction in Progress 0    
Total 1,097,587    
Accumulated Depreciation $ 214,533    
Year(s) Built / Renovated 1976    
Year(s) Acquired 2010    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 250 West 55th Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 51,928    
Land and improvements 285,263    
Buildings and Improvements 655,095    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 940,358    
Accumulated Depreciation $ 116,857    
Year(s) Built / Renovated 2014    
Year(s) Acquired 2007    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 100 Federal Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 102,984    
Land and improvements 131,067    
Buildings and Improvements 538,938    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 670,005    
Accumulated Depreciation $ 122,799    
Year(s) Built / Renovated 1971-1975/2017    
Year(s) Acquired 2012    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Times Square Tower      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 75,243    
Land and improvements 159,694    
Buildings and Improvements 461,400    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 621,094    
Accumulated Depreciation $ 207,272    
Year(s) Built / Renovated 2004    
Year(s) Acquired 2000    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Carnegie Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Carnegie Center    
Type Office    
Location Princeton, NJ    
Encumbrances $ 0    
Original Land 142,666    
Original Building 316,856    
Costs Capitalized Subsequent to Acquisition 137,317    
Land and improvements 90,498    
Buildings and Improvements 451,661    
Land Held for Development 54,680    
Development and Construction in Progress 0    
Total 596,839    
Accumulated Depreciation $ 204,380    
Year(s) Built / Renovated 1983-2016    
Year(s) Acquired 1998/1999/2000/2007/2014/2017/2019    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Atlantic Wharf      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 18,709    
Land and improvements 63,988    
Buildings and Improvements 473,246    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 537,234    
Accumulated Depreciation $ 131,828    
Year(s) Built / Renovated 2011    
Year(s) Acquired 2007    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 510 Madison Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 25,495    
Land and improvements 103,000    
Buildings and Improvements 279,160    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 382,160    
Accumulated Depreciation $ 72,213    
Year(s) Built / Renovated 2012    
Year(s) Acquired 2010    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Fountain Square      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Fountain Square    
Type Office    
Location Reston, VA    
Encumbrances $ 0    
Original Land 56,853    
Original Building 306,298    
Costs Capitalized Subsequent to Acquisition 12,140    
Land and improvements 56,853    
Buildings and Improvements 318,438    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 375,291    
Accumulated Depreciation $ 78,498    
Year(s) Built / Renovated 1986-1990    
Year(s) Acquired 2012    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 599 Lexington Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 599 Lexington Avenue    
Type Office    
Location New York, NY    
Encumbrances $ 0    
Original Land 81,040    
Original Building 100,507    
Costs Capitalized Subsequent to Acquisition 161,330    
Land and improvements 81,040    
Buildings and Improvements 261,837    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 342,877    
Accumulated Depreciation $ 176,101    
Year(s) Built / Renovated 1986    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 680 Folsom Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 7,907    
Land and improvements 72,545    
Buildings and Improvements 227,673    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 300,218    
Accumulated Depreciation $ 46,777    
Year(s) Built / Renovated 2014    
Year(s) Acquired 2012    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 2200 Pennsylvania Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 113,627    
Land and improvements 109,038    
Buildings and Improvements 188,130    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 297,168    
Accumulated Depreciation $ 59,190    
Year(s) Built / Renovated 2011    
Year(s) Acquired 2008    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 145 Broadway      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 145 Broadway    
Type Office    
Location Cambridge, MA    
Encumbrances $ 0    
Original Land 121    
Original Building 273,013    
Costs Capitalized Subsequent to Acquisition 23,043    
Land and improvements 23,164    
Buildings and Improvements 273,013    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 296,177    
Accumulated Depreciation $ 1,511    
Year(s) Built / Renovated 2019    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | South of Market and Democracy Tower      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 26,079    
Land and improvements 13,603    
Buildings and Improvements 263,558    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 277,161    
Accumulated Depreciation $ 99,406    
Year(s) Built / Renovated 2008-2009    
Year(s) Acquired 2003    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 601 Massachusetts Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 601 Massachusetts Avenue    
Type Office    
Location Washington, DC    
Encumbrances $ 0    
Original Land 95,310    
Original Building 165,173    
Costs Capitalized Subsequent to Acquisition 3,933    
Land and improvements 95,310    
Buildings and Improvements 169,106    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 264,416    
Accumulated Depreciation $ 24,502    
Year(s) Built / Renovated 2016    
Year(s) Acquired 2008    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Bay Colony Corporate Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 80,077    
Land and improvements 18,789    
Buildings and Improvements 228,528    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 247,317    
Accumulated Depreciation $ 79,824    
Year(s) Built / Renovated 1985-1989    
Year(s) Acquired 2011    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Gateway Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Gateway Center    
Type Office    
Location San Francisco, CA    
Encumbrances $ 0    
Original Land 28,255    
Original Building 139,245    
Costs Capitalized Subsequent to Acquisition 55,402    
Land and improvements 29,029    
Buildings and Improvements 193,873    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 222,902    
Accumulated Depreciation $ 104,993    
Year(s) Built / Renovated 1984/1986/2002    
Year(s) Acquired 1999    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 535 Mission Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 3,276    
Land and improvements 40,933    
Buildings and Improvements 151,654    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 192,587    
Accumulated Depreciation $ 26,293    
Year(s) Built / Renovated 2015    
Year(s) Acquired 2013    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Mountain View Research Park      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 12,704    
Land and improvements 95,066    
Buildings and Improvements 81,077    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 176,143    
Accumulated Depreciation $ 19,807    
Year(s) Built / Renovated 1977-1981/2007-2013    
Year(s) Acquired 2013    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Reservoir Place      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Reservoir Place    
Type Office    
Location Waltham, MA    
Encumbrances $ 0    
Original Land 18,605    
Original Building 104,124    
Costs Capitalized Subsequent to Acquisition 49,643    
Land and improvements 19,089    
Buildings and Improvements 153,283    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 172,372    
Accumulated Depreciation $ 69,794    
Year(s) Built / Renovated 1955/1987/2017    
Year(s) Acquired 1997/1998    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 1330 Connecticut Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 1330 Connecticut Avenue    
Type Office    
Location Washington, DC    
Encumbrances $ 0    
Original Land 25,982    
Original Building 82,311    
Costs Capitalized Subsequent to Acquisition 32,234    
Land and improvements 25,982    
Buildings and Improvements 114,545    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 140,527    
Accumulated Depreciation $ 31,553    
Year(s) Built / Renovated 1984/2018    
Year(s) Acquired 2004    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Kingstowne Towne Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 3,212    
Land and improvements 18,021    
Buildings and Improvements 112,250    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 130,271    
Accumulated Depreciation $ 44,258    
Year(s) Built / Renovated 2003-2006    
Year(s) Acquired 2007    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | One Freedom Square      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name One Freedom Square    
Type Office    
Location Reston, VA    
Encumbrances $ 0    
Original Land 9,929    
Original Building 84,504    
Costs Capitalized Subsequent to Acquisition 28,735    
Land and improvements 9,883    
Buildings and Improvements 113,285    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 123,168    
Accumulated Depreciation $ 57,516    
Year(s) Built / Renovated 2000    
Year(s) Acquired 2003    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Weston Corporate Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 $ 29,227    
Year(s) Built / Renovated 2010    
Year(s) Acquired 2001    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Capital Gallery      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 78,573    
Land and improvements 6,128    
Buildings and Improvements 106,735    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 112,863    
Accumulated Depreciation $ 68,953    
Year(s) Built / Renovated 1981/2006    
Year(s) Acquired 2007    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Two Freedom Square      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Two Freedom Square    
Type Office    
Location Reston, VA    
Encumbrances $ 0    
Original Land 13,930    
Original Building 77,739    
Costs Capitalized Subsequent to Acquisition 16,997    
Land and improvements 13,866    
Buildings and Improvements 94,800    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 108,666    
Accumulated Depreciation $ 49,028    
Year(s) Built / Renovated 2001    
Year(s) Acquired 2003    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | One and Two Reston Overlook      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 19,763    
Land and improvements 15,074    
Buildings and Improvements 87,337    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 102,411    
Accumulated Depreciation $ 50,336    
Year(s) Built / Renovated 1999    
Year(s) Acquired 2000    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 355 Main Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 355 Main Street    
Type Office    
Location Cambridge, MA    
Encumbrances $ 0    
Original Land 18,863    
Original Building 53,346    
Costs Capitalized Subsequent to Acquisition 27,284    
Land and improvements 21,098    
Buildings and Improvements 78,395    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 99,493    
Accumulated Depreciation $ 26,362    
Year(s) Built / Renovated 1981/1996/2013    
Year(s) Acquired 2006    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 140 Kendrick Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 13,584    
Land and improvements 18,095    
Buildings and Improvements 80,489    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 98,584    
Accumulated Depreciation $ 34,667    
Year(s) Built / Renovated 2000    
Year(s) Acquired 2004    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Discovery Square      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 15,360    
Land and improvements 11,146    
Buildings and Improvements 87,194    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 98,340    
Accumulated Depreciation $ 42,152    
Year(s) Built / Renovated 2001    
Year(s) Acquired 2003    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 880 & 890 Winter Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 880 & 890 Winter Street    
Type Office    
Location Waltham, MA    
Encumbrances $ 0    
Original Land 29,510    
Original Building 65,812    
Costs Capitalized Subsequent to Acquisition 0    
Land and improvements 29,510    
Buildings and Improvements 65,812    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 95,322    
Accumulated Depreciation $ 1,458    
Year(s) Built / Renovated 1998-1999    
Year(s) Acquired 2019    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 10 CityPoint      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 10 CityPoint    
Type Office    
Location Waltham, MA    
Encumbrances $ 0    
Original Land 1,953    
Original Building 85,752    
Costs Capitalized Subsequent to Acquisition 4,534    
Land and improvements 2,127    
Buildings and Improvements 90,112    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 92,239    
Accumulated Depreciation $ 10,928    
Year(s) Built / Renovated 2016    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 90 Broadway      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 19,678    
Land and improvements 20,741    
Buildings and Improvements 70,119    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 90,860    
Accumulated Depreciation $ 23,581    
Year(s) Built / Renovated 1983/1998/2013    
Year(s) Acquired 2006    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 77 CityPoint      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 10,451    
Land and improvements 13,997    
Buildings and Improvements 70,684    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 84,681    
Accumulated Depreciation $ 27,148    
Year(s) Built / Renovated 2008    
Year(s) Acquired 2001    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 230 CityPoint      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 230 CityPoint    
Type Office    
Location Waltham, MA    
Encumbrances $ 0    
Original Land 13,189    
Original Building 49,823    
Costs Capitalized Subsequent to Acquisition 20,440    
Land and improvements 13,403    
Buildings and Improvements 70,049    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 83,452    
Accumulated Depreciation $ 28,831    
Year(s) Built / Renovated 1992    
Year(s) Acquired 2005    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Waltham Weston Corporate Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Waltham Weston Corporate Center    
Type Office    
Location Waltham, MA    
Encumbrances $ 0    
Original Land 10,385    
Original Building 60,694    
Costs Capitalized Subsequent to Acquisition 10,178    
Land and improvements 10,350    
Buildings and Improvements 70,907    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 81,257    
Accumulated Depreciation $ 34,777    
Year(s) Built / Renovated 2003    
Year(s) Acquired 1999    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 3625-3635 Peterson Way      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 3625-3635 Peterson Way    
Type Office    
Location Santa Clara, CA    
Encumbrances $ 0    
Original Land 63,206    
Original Building 14,879    
Costs Capitalized Subsequent to Acquisition 752    
Land and improvements 63,206    
Buildings and Improvements 14,879    
Land Held for Development 752    
Development and Construction in Progress 0    
Total 78,837    
Accumulated Depreciation $ 11,172    
Year(s) Built / Renovated 1979    
Year(s) Acquired 2016    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 2440 West El Camino Real      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 5,454    
Land and improvements 16,741    
Buildings and Improvements 56,739    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 73,480    
Accumulated Depreciation $ 13,090    
Year(s) Built / Renovated 1987/2003    
Year(s) Acquired 2011    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 191 Spring Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 59,751    
Costs Capitalized Subsequent to Acquisition 7,063    
Land and improvements 2,850    
Buildings and Improvements 66,814    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 69,664    
Accumulated Depreciation $ 21,801    
Year(s) Built / Renovated 1971/1995/2018    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 300 Binney Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 $ 11,146    
Year(s) Built / Renovated 2013    
Year(s) Acquired 2009    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Wisconsin Place      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 14,924    
Land and improvements 0    
Buildings and Improvements 68,273    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 68,273    
Accumulated Depreciation $ 25,934    
Year(s) Built / Renovated 2009    
Year(s) Acquired 2004    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Reston Corporate Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 3,625    
Land and improvements 9,496    
Buildings and Improvements 54,121    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 63,617    
Accumulated Depreciation $ 29,170    
Year(s) Built / Renovated 1984    
Year(s) Acquired 1998    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | New Dominion Technology Park, Bldg. Two      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 412    
Land and improvements 5,574    
Buildings and Improvements 52,290    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 57,864    
Accumulated Depreciation $ 25,900    
Year(s) Built / Renovated 2004    
Year(s) Acquired 1998    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 255 Main Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 32,468    
Land and improvements 134    
Buildings and Improvements 57,578    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 57,712    
Accumulated Depreciation $ 33,108    
Year(s) Built / Renovated 1987    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | University Place      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name University Place    
Type Office    
Location Cambridge, MA    
Encumbrances $ 3,602    
Original Land 0    
Original Building 37,091    
Costs Capitalized Subsequent to Acquisition 14,551    
Land and improvements 7,055    
Buildings and Improvements 44,587    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 51,642    
Accumulated Depreciation $ 29,044    
Year(s) Built / Renovated 1985    
Year(s) Acquired 1998    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Sumner Square      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Sumner Square    
Type Office    
Location Washington, DC    
Encumbrances $ 0    
Original Land 624    
Original Building 28,745    
Costs Capitalized Subsequent to Acquisition 19,264    
Land and improvements 3,015    
Buildings and Improvements 45,618    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 48,633    
Accumulated Depreciation $ 26,547    
Year(s) Built / Renovated 1985    
Year(s) Acquired 1999    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | New Dominion Technology Park, Bldg. One      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name New Dominion Technology Park, Bldg. One    
Type Office    
Location Herndon, VA    
Encumbrances $ 0    
Original Land 3,880    
Original Building 43,227    
Costs Capitalized Subsequent to Acquisition 1,117    
Land and improvements 3,880    
Buildings and Improvements 44,344    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 48,224    
Accumulated Depreciation $ 28,398    
Year(s) Built / Renovated 2001    
Year(s) Acquired 1998    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 200 West Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 5,550    
Land and improvements 16,148    
Buildings and Improvements 28,429    
Land Held for Development 0    
Development and Construction in Progress 2,104    
Total 46,681    
Accumulated Depreciation $ 16,298    
Year(s) Built / Renovated 1999    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | North First Business Park      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name North First Business Park    
Type Office    
Location San Jose, CA    
Encumbrances $ 0    
Original Land 23,398    
Original Building 13,069    
Costs Capitalized Subsequent to Acquisition 4,548    
Land and improvements 23,371    
Buildings and Improvements 17,644    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 41,015    
Accumulated Depreciation $ 16,411    
Year(s) Built / Renovated 1981    
Year(s) Acquired 2007    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 150 Broadway      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 6,535    
Land and improvements 822    
Buildings and Improvements 31,605    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 32,427    
Accumulated Depreciation $ 19,342    
Year(s) Built / Renovated 1999    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 105 Broadway      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 9,300    
Land and improvements 1,868    
Buildings and Improvements 21,674    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 23,542    
Accumulated Depreciation $ 11,312    
Year(s) Built / Renovated 1990    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Lexington Office Park      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Lexington Office Park    
Type Office    
Location Lexington, MA    
Encumbrances $ 0    
Original Land 998    
Original Building 1,426    
Costs Capitalized Subsequent to Acquisition 17,783    
Land and improvements 1,073    
Buildings and Improvements 19,134    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 20,207    
Accumulated Depreciation $ 14,114    
Year(s) Built / Renovated 1982    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 201 Spring Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 73    
Land and improvements 2,849    
Buildings and Improvements 15,376    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 18,225    
Accumulated Depreciation $ 8,295    
Year(s) Built / Renovated 1997    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | The Point      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name The Point    
Type Office    
Location Waltham, MA    
Encumbrances $ 0    
Original Land 6,395    
Original Building 10,040    
Costs Capitalized Subsequent to Acquisition 421    
Land and improvements 6,492    
Buildings and Improvements 10,364    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 16,856    
Accumulated Depreciation $ 1,349    
Year(s) Built / Renovated 2015    
Year(s) Acquired 2007    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 33 Hayden Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 12,261    
Land and improvements 266    
Buildings and Improvements 15,495    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 15,761    
Accumulated Depreciation $ 5,510    
Year(s) Built / Renovated 1979    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 690 Folsom Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 690 Folsom Street    
Type Office    
Location San Francisco, CA    
Encumbrances $ 0    
Original Land 3,219    
Original Building 11,038    
Costs Capitalized Subsequent to Acquisition 1,157    
Land and improvements 3,219    
Buildings and Improvements 12,195    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 15,414    
Accumulated Depreciation $ 2,284    
Year(s) Built / Renovated 2015    
Year(s) Acquired 2012    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 92-100 Hayden Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 6,800    
Land and improvements 619    
Buildings and Improvements 13,523    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 14,142    
Accumulated Depreciation $ 11,847    
Year(s) Built / Renovated 1985    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 181 Spring Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 1,800    
Land and improvements 1,066    
Buildings and Improvements 11,320    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 12,386    
Accumulated Depreciation $ 5,498    
Year(s) Built / Renovated 1999    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 195 West Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 3,229    
Land and improvements 1,611    
Buildings and Improvements 9,881    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 11,492    
Accumulated Depreciation $ 8,087    
Year(s) Built / Renovated 1990    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 7501 Boston Boulevard, Building Seven      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 311    
Land and improvements 665    
Buildings and Improvements 9,584    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 10,249    
Accumulated Depreciation $ 5,257    
Year(s) Built / Renovated 1997    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 7435 Boston Boulevard, Building One      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 4,290    
Land and improvements 486    
Buildings and Improvements 8,018    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 8,504    
Accumulated Depreciation $ 6,162    
Year(s) Built / Renovated 1982    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 7450 Boston Boulevard, Building Three      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 2,177    
Land and improvements 1,327    
Buildings and Improvements 6,696    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 8,023    
Accumulated Depreciation $ 3,462    
Year(s) Built / Renovated 1987    
Year(s) Acquired 1998    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 32 Hartwell Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 5,529    
Land and improvements 168    
Buildings and Improvements 7,472    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 7,640    
Accumulated Depreciation $ 1,819    
Year(s) Built / Renovated 1968/1979/1987    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 250 Binney Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 $ 5,660    
Year(s) Built / Renovated 1983    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 8000 Grainger Court, Building Five      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 2,604    
Land and improvements 453    
Buildings and Improvements 6,799    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 7,252    
Accumulated Depreciation $ 5,597    
Year(s) Built / Renovated 1984    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 453 Ravendale Drive      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 676    
Land and improvements 5,477    
Buildings and Improvements 1,766    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 7,243    
Accumulated Depreciation $ 690    
Year(s) Built / Renovated 1977    
Year(s) Acquired 2012    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 7300 Boston Boulevard, Building Thirteen      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 795    
Land and improvements 608    
Buildings and Improvements 5,568    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 6,176    
Accumulated Depreciation $ 1,928    
Year(s) Built / Renovated 2002    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 17 Hartwell Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 17 Hartwell Avenue    
Type Office    
Location Lexington, MA    
Encumbrances $ 0    
Original Land 26    
Original Building 150    
Costs Capitalized Subsequent to Acquisition 5,907    
Land and improvements 26    
Buildings and Improvements 6,057    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 6,083    
Accumulated Depreciation $ 1,924    
Year(s) Built / Renovated 1968    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 7601 Boston Boulevard, Building Eight      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 4,367    
Land and improvements 378    
Buildings and Improvements 5,067    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 5,445    
Accumulated Depreciation $ 4,507    
Year(s) Built / Renovated 1986    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 7500 Boston Boulevard, Building Six      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 7500 Boston Boulevard, Building Six    
Type Office    
Location Springfield, VA    
Encumbrances $ 0    
Original Land 138    
Original Building 3,749    
Costs Capitalized Subsequent to Acquisition 1,107    
Land and improvements 234    
Buildings and Improvements 4,760    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 4,994    
Accumulated Depreciation $ 4,097    
Year(s) Built / Renovated 1985    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 8000 Corporate Court, Building Eleven      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 1,245    
Land and improvements 686    
Buildings and Improvements 3,766    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 4,452    
Accumulated Depreciation $ 3,094    
Year(s) Built / Renovated 1989    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 7375 Boston Boulevard, Building Ten      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 851    
Land and improvements 47    
Buildings and Improvements 3,512    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 3,559    
Accumulated Depreciation $ 2,562    
Year(s) Built / Renovated 1988    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 7374 Boston Boulevard, Building Four      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 1,445    
Land and improvements 303    
Buildings and Improvements 2,988    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 3,291    
Accumulated Depreciation $ 2,681    
Year(s) Built / Renovated 1984    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | 7451 Boston Boulevard, Building Two      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 1,354    
Land and improvements 535    
Buildings and Improvements 2,610    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 3,145    
Accumulated Depreciation $ 2,526    
Year(s) Built / Renovated 1982    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Signature at Reston      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Signature at Reston    
Type Residential    
Location Reston, VA    
Encumbrances $ 0    
Original Land 27,076    
Original Building 190,580    
Costs Capitalized Subsequent to Acquisition 393    
Land and improvements 27,076    
Buildings and Improvements 190,973    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 218,049    
Accumulated Depreciation $ 8,773    
Year(s) Built / Renovated 2018    
Year(s) Acquired 2013    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Proto Kendall Square      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Proto Kendall Square    
Type Residential    
Location Cambridge, MA    
Encumbrances $ 0    
Original Land 9,243    
Original Building 127,248    
Costs Capitalized Subsequent to Acquisition 2,939    
Land and improvements 9,245    
Buildings and Improvements 130,185    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 139,430    
Accumulated Depreciation $ 4,566    
Year(s) Built / Renovated 2018    
Year(s) Acquired 2015    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | The Avant at Reston Town Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 830    
Land and improvements 20,350    
Buildings and Improvements 92,825    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 113,175    
Accumulated Depreciation $ 14,728    
Year(s) Built / Renovated 2014    
Year(s) Acquired 2010    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | The Lofts at Atlantic Wharf      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 1,897    
Land and improvements 3,529    
Buildings and Improvements 56,788    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 60,317    
Accumulated Depreciation $ 12,639    
Year(s) Built / Renovated 2011    
Year(s) Acquired 2007    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Boston Marriott Cambridge      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 32,922    
Land and improvements 478    
Buildings and Improvements 70,840    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 71,318    
Accumulated Depreciation $ 45,842    
Year(s) Built / Renovated 1986/2017    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Kendall Center Green Garage      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Kendall Center Green Garage    
Type Garage    
Location Cambridge, MA    
Encumbrances $ 0    
Original Land 0    
Original Building 35,035    
Costs Capitalized Subsequent to Acquisition 6,915    
Land and improvements 0    
Buildings and Improvements 41,950    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 41,950    
Accumulated Depreciation $ 13,404    
Year(s) Built / Renovated 1984    
Year(s) Acquired 2006    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Kendall Center Yellow Garage      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Kendall Center Yellow Garage    
Type Garage    
Location Cambridge, MA    
Encumbrances $ 0    
Original Land 1,256    
Original Building 15,697    
Costs Capitalized Subsequent to Acquisition 840    
Land and improvements 1,256    
Buildings and Improvements 16,537    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 17,793    
Accumulated Depreciation $ 5,847    
Year(s) Built / Renovated 2006    
Year(s) Acquired 2004    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | Kendall Center Blue Garage      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Kendall Center Blue Garage    
Type Garage    
Location Cambridge, MA    
Encumbrances $ 0    
Original Land 1,163    
Original Building 11,633    
Costs Capitalized Subsequent to Acquisition 486    
Land and improvements 1,163    
Buildings and Improvements 12,119    
Land Held for Development 0    
Development and Construction in Progress 0    
Total 13,282    
Accumulated Depreciation $ 9,290    
Year(s) Built / Renovated 1990    
Year(s) Acquired 1997    
Depreciable Lives (Years) [10] (1)    
Boston Properties Limited Partnership | The Skylyne (MacArthur Station Residences)      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name The Skylyne (MacArthur Station Residences)    
Type Development    
Location Oakland, CA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 226,526    
Land and improvements 29,807    
Buildings and Improvements 0    
Land Held for Development 0    
Development and Construction in Progress 196,719    
Total 226,526    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired N/A    
Depreciable Lives (Years) N/A    
Boston Properties Limited Partnership | 2100 Pennsylvania Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 2100 Pennsylvania Avenue    
Type Development    
Location Washington, DC    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 224,380    
Land and improvements 185,129    
Buildings and Improvements 0    
Land Held for Development 0    
Development and Construction in Progress 39,251    
Total 224,380    
Accumulated Depreciation $ 1,024    
Year(s) Built / Renovated N/A    
Year(s) Acquired N/A    
Depreciable Lives (Years) N/A    
Boston Properties Limited Partnership | Reston Gateway      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Reston Gateway    
Type Development    
Location Reston, VA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 150,632    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 0    
Development and Construction in Progress 150,632    
Total 150,632    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 1998    
Depreciable Lives (Years) N/A    
Boston Properties Limited Partnership | 17Fifty Presidents Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 17Fifty Presidents Street    
Type Development    
Location Reston, VA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 99,816    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 0    
Development and Construction in Progress 99,816    
Total 99,816    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2013    
Depreciable Lives (Years) N/A    
Boston Properties Limited Partnership | 20 CityPoint      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 20 CityPoint    
Type Development    
Location Waltham, MA    
Encumbrances $ 0    
Original Land 4,721    
Original Building 52,039    
Costs Capitalized Subsequent to Acquisition 20,007    
Land and improvements 4,721    
Buildings and Improvements 52,039    
Land Held for Development 0    
Development and Construction in Progress 20,007    
Total 76,767    
Accumulated Depreciation $ 1,136    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2007    
Depreciable Lives (Years) N/A    
Boston Properties Limited Partnership | 325 Main Street      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 325 Main Street    
Type Development    
Location Cambridge, MA    
Encumbrances $ 0    
Original Land 174    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 68,710    
Land and improvements 772    
Buildings and Improvements 0    
Land Held for Development 0    
Development and Construction in Progress 68,112    
Total 68,884    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 1997    
Depreciable Lives (Years) N/A    
Boston Properties Limited Partnership | North First Master Plan      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name North First Master Plan    
Type Land    
Location San Jose, CA    
Encumbrances $ 0    
Original Land 35,004    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 3,932    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 38,936    
Development and Construction in Progress 0    
Total 38,936    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2007    
Depreciable Lives (Years) N/A    
Boston Properties Limited Partnership | Plaza at Almaden      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 34,889    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 34,889    
Development and Construction in Progress 0    
Total 34,889    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2006    
Depreciable Lives (Years) N/A    
Boston Properties Limited Partnership | 4th and Harrison      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 425 Fourth Street    
Type Land    
Location San Francisco, CA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 22,074    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 22,074    
Development and Construction in Progress 0    
Total 22,074    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired N/A    
Depreciable Lives (Years) N/A    
Boston Properties Limited Partnership | Springfield Metro Center      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 19,844    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 19,844    
Development and Construction in Progress 0    
Total 19,844    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2007    
Depreciable Lives (Years) N/A    
Boston Properties Limited Partnership | Reston Gateway Master Plan      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Reston Gateway Master Plan    
Type Land    
Location Reston, VA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 18,292    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 18,292    
Development and Construction in Progress 0    
Total 18,292    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 1998    
Depreciable Lives (Years) N/A    
Boston Properties Limited Partnership | 214 Third Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 17,692    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 17,692    
Development and Construction in Progress 0    
Total 17,692    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2006    
Depreciable Lives (Years) N/A    
Boston Properties Limited Partnership | 103 Fourth Avenue      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name 103 Fourth Avenue    
Type Land    
Location Waltham, MA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 12,826    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 12,826    
Development and Construction in Progress 0    
Total 12,826    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2007    
Depreciable Lives (Years) N/A    
Boston Properties Limited Partnership | Crane Meadow      
SEC Schedule, 12-28, Real Estate Companies, Investment in 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 8,866    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 8,866    
Development and Construction in Progress 0    
Total 8,866    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2000    
Depreciable Lives (Years) N/A    
Boston Properties Limited Partnership | Broad Run Business Park      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Broad Run Business Park    
Type Land    
Location Loudoun County, VA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 2,396    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 2,396    
Development and Construction in Progress 0    
Total 2,396    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 1998    
Depreciable Lives (Years) N/A    
Boston Properties Limited Partnership | Kendall Center Master Plan      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Kendall Center Master Plan    
Type Land    
Location Cambridge, MA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 1,693    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 1,693    
Development and Construction in Progress 0    
Total 1,693    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 1997    
Depreciable Lives (Years) N/A    
Boston Properties Limited Partnership | Weston Quarry      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Weston Quarry    
Type Land    
Location Weston, MA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 1,249    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 1,249    
Development and Construction in Progress 0    
Total 1,249    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2001    
Depreciable Lives (Years) N/A    
Boston Properties Limited Partnership | Reston Overlook Master Plan      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Property Name Reston Overlook Master Plan    
Type Land    
Location Reston, VA    
Encumbrances $ 0    
Original Land 0    
Original Building 0    
Costs Capitalized Subsequent to Acquisition 39    
Land and improvements 0    
Buildings and Improvements 0    
Land Held for Development 39    
Development and Construction in Progress 0    
Total 39    
Accumulated Depreciation $ 0    
Year(s) Built / Renovated N/A    
Year(s) Acquired 2000    
Depreciable Lives (Years) N/A    
Minimum [Member]      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Real Estate and Accumulated Depreiation Life used for Depreciation life of the lease    
Minimum [Member] | Boston Properties Limited Partnership      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Real Estate and Accumulated Depreiation Life used for Depreciation life of the lease    
Maximum [Member]      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Real Estate and Accumulated Depreciation, Life Used for Depreciation 40 years    
Maximum [Member] | Boston Properties Limited Partnership      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Real Estate and Accumulated Depreciation, Life Used for Depreciation 40 years    
Furniture and Fixtures [Member]      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Accumulated Depreciation $ 27,619    
Furniture and Fixtures [Member] | Boston Properties Limited Partnership      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Accumulated Depreciation 27,619    
Land and Land Improvements [Member]      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Right-of-use assets - finance leases 214,091    
Land and Land Improvements [Member] | Boston Properties Limited Partnership      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Right-of-use assets - finance leases 214,091    
Building and Building Improvements [Member]      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Right-of-use assets - finance leases 23,303    
Building and Building Improvements [Member] | Boston Properties Limited Partnership      
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]      
Right-of-use assets - finance leases $ 23,303    
[1]
Includes unamortized deferred financing costs totaling approximately $(26.7) million.
[2]
Includes Right of Use Assets - Finance Leases and Right of Use Assets - Operating Leases of approximately $214,091 and $148,640, respectively.
[3]
Includes Right of Use Assets - Finance Leases of approximately $23,303.
[4]
Includes pre-development costs.
[5]
Depreciation of the buildings and improvements are calculated over lives ranging from the life of the lease to 40 years.
[6]
Includes unamortized deferred financing costs totaling approximately $(26.7) million.
[7]
Includes Right of Use Assets - Finance Leases and Right of Use Assets - Operating Leases of approximately $214,091 and $148,640, respectively.
[8]
Includes Right of Use Assets - Finance Leases of approximately $23,303.
[9]
Includes pre-development costs.
[10]
Depreciation of the buildings and improvements are calculated over lives ranging from the life of the lease to 40 years.