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SEC Schedule, Article 12-28, Real Estate and Accumulated Depreciation (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2022
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]        
Encumbrances [1] $ 3,272,368      
Original Cost        
Original Land 5,373,987      
Original Building 14,755,092      
Costs Capitalized Subsequent to Acquisition 5,615,135      
Land and Improvements [2] 5,571,327      
Building and Improvements [3] 19,044,812      
Land held for development [4] 721,501 $ 560,355    
Development and Construction in Progress 406,574 894,172    
Total 25,744,214 24,108,220 $ 23,303,303 $ 22,844,697
Accumulated Depreciation 6,260,992 5,848,183 5,501,637 5,239,179
Furniture, Fixtures and Equipment 50,310 51,695    
Aggregate cost for tax purpose 23,100,000      
Real Estate Aggregate Accumulated Depreciation For Tax Purposes 5,000,000      
Right-of-use assets - finance leases 237,510 237,507    
Right of use assets - operating leases $ 167,351 169,778    
Maximum [Member]        
Original Cost        
Real Estate and Accumulated Depreciation, Life Used for Depreciation 40 years      
Furniture, fixtures, and equipment        
Original Cost        
Accumulated Depreciation Related to Furniture, Fixtures and Equipment $ 37,090      
Land and Land Improvements [Member]        
Original Cost        
Right-of-use assets - finance leases 214,165      
Right of use assets - operating leases 167,351      
Buildings and improvements        
Original Cost        
Right-of-use assets - finance leases 23,345      
767Fifth Avenue (the General Motors Building) | Office Building [Member]        
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]        
Encumbrances 2,284,510      
Original Cost        
Original Land 1,796,252      
Original Building 1,532,654      
Costs Capitalized Subsequent to Acquisition 325,762      
Land and Improvements 1,796,252      
Building and Improvements 1,858,416      
Total 3,654,668      
Accumulated Depreciation $ 457,344      
Depreciable Lives (Years) [5] (1)      
Prudential Center | Office Building [Member]        
Original Cost        
Original Land $ 92,077      
Original Building 948,357      
Costs Capitalized Subsequent to Acquisition 718,028      
Land and Improvements 115,639      
Building and Improvements 1,510,834      
Land held for development 231      
Development and Construction in Progress 131,758      
Total 1,758,462      
Accumulated Depreciation $ 721,498      
Depreciable Lives (Years) [5] (1)      
Embarcadero Center | Office Building [Member]        
Original Cost        
Original Land $ 179,697      
Original Building 847,410      
Costs Capitalized Subsequent to Acquisition 499,451      
Land and Improvements 195,986      
Building and Improvements 1,330,572      
Total 1,526,558      
Accumulated Depreciation $ 736,748      
Depreciable Lives (Years) [5] (1)      
399 Park Avenue | Office Building [Member]        
Original Cost        
Original Land $ 339,200      
Original Building 700,358      
Costs Capitalized Subsequent to Acquisition 393,821      
Land and Improvements 354,107      
Building and Improvements 1,079,272      
Total 1,433,379      
Accumulated Depreciation $ 445,239      
Depreciable Lives (Years) [5] (1)      
601 Lexington Avenue | Office Building [Member]        
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]        
Encumbrances $ 987,858      
Original Cost        
Original Land 241,600      
Original Building 494,782      
Costs Capitalized Subsequent to Acquisition 515,644      
Land and Improvements 289,639      
Building and Improvements 962,387      
Total 1,252,026      
Accumulated Depreciation $ 348,892      
Depreciable Lives (Years) [5] (1)      
Salesforce Tower | Office Building [Member]        
Original Cost        
Original Land $ 200,349      
Original Building 946,205      
Costs Capitalized Subsequent to Acquisition 7,462      
Land and Improvements 200,349      
Building and Improvements 953,667      
Total 1,154,016      
Accumulated Depreciation $ 129,281      
Depreciable Lives (Years) [5] (1)      
200 Clarendon Street and Garage | Office Building [Member]        
Original Cost        
Original Land $ 219,543      
Original Building 667,884      
Costs Capitalized Subsequent to Acquisition 235,129      
Land and Improvements 250,512      
Building and Improvements 872,044      
Total 1,122,556      
Accumulated Depreciation $ 310,318      
Depreciable Lives (Years) [5] (1)      
250 West 55th Street | Office Building [Member]        
Original Cost        
Original Land $ 285,263      
Original Building 603,167      
Costs Capitalized Subsequent to Acquisition 51,800      
Land and Improvements 285,263      
Building and Improvements 654,967      
Total 940,230      
Accumulated Depreciation $ 179,143      
Depreciable Lives (Years) [5] (1)      
100 Federal Street | Office Building [Member]        
Original Cost        
Original Land $ 131,067      
Original Building 435,954      
Costs Capitalized Subsequent to Acquisition 119,341      
Land and Improvements 131,067      
Building and Improvements 555,295      
Total 686,362      
Accumulated Depreciation $ 157,368      
Depreciable Lives (Years) [5] (1)      
Madison Centre | Office Building [Member]        
Original Cost        
Original Land $ 104,641      
Original Building 564,336      
Costs Capitalized Subsequent to Acquisition 2,879      
Land and Improvements 104,641      
Building and Improvements 567,215      
Total 671,856      
Accumulated Depreciation $ 13,611      
Depreciable Lives (Years) [5] (1)      
Times Square Tower | Office Building [Member]        
Original Cost        
Original Land $ 165,413      
Original Building 380,438      
Costs Capitalized Subsequent to Acquisition 121,437      
Land and Improvements 169,193      
Building and Improvements 498,095      
Total 667,288      
Accumulated Depreciation $ 241,474      
Depreciable Lives (Years) [5] (1)      
Carnegie Center | Office Building [Member]        
Original Cost        
Original Land $ 142,666      
Original Building 316,856      
Costs Capitalized Subsequent to Acquisition 168,261      
Land and Improvements 94,243      
Building and Improvements 476,990      
Land held for development 55,919      
Development and Construction in Progress 631      
Total 627,783      
Accumulated Depreciation $ 252,390      
Depreciable Lives (Years) [5] (1)      
125 Broadway | Office Building [Member]        
Original Cost        
Original Land $ 126,364      
Original Building 433,662      
Costs Capitalized Subsequent to Acquisition 58      
Land and Improvements 126,364      
Building and Improvements 433,720      
Total 560,084      
Accumulated Depreciation $ 4,503      
Depreciable Lives (Years) [5] (1)      
Atlantic Wharf | Office Building [Member]        
Original Cost        
Original Land $ 63,988      
Original Building 454,537      
Costs Capitalized Subsequent to Acquisition 24,158      
Land and Improvements 63,988      
Building and Improvements 478,695      
Total 542,683      
Accumulated Depreciation $ 171,876      
Depreciable Lives (Years) [5] (1)      
Reston Next | Office Building [Member]        
Original Cost        
Original Land $ 2,901      
Original Building 525,277      
Costs Capitalized Subsequent to Acquisition 0      
Land and Improvements 2,901      
Building and Improvements 525,277      
Total 528,178      
Accumulated Depreciation $ 15,293      
Depreciable Lives (Years) [5] (1)      
599 Lexington Avenue | Office Building [Member]        
Original Cost        
Original Land $ 81,040      
Original Building 100,507      
Costs Capitalized Subsequent to Acquisition 245,609      
Land and Improvements 87,852      
Building and Improvements 339,304      
Total 427,156      
Accumulated Depreciation $ 182,121      
Depreciable Lives (Years) [5] (1)      
Fountain Square | Office Building [Member]        
Original Cost        
Original Land $ 56,853      
Original Building 306,298      
Costs Capitalized Subsequent to Acquisition 39,288      
Land and Improvements 56,853      
Building and Improvements 345,586      
Total 402,439      
Accumulated Depreciation $ 104,864      
Depreciable Lives (Years) [5] (1)      
510 Madison Avenue | Office Building [Member]        
Original Cost        
Original Land $ 103,000      
Original Building 253,665      
Costs Capitalized Subsequent to Acquisition 31,682      
Land and Improvements 103,000      
Building and Improvements 285,347      
Total 388,347      
Accumulated Depreciation $ 95,520      
Depreciable Lives (Years) [5] (1)      
325 Main Street | Office Building [Member]        
Original Cost        
Original Land $ 21,596      
Original Building 312,492      
Costs Capitalized Subsequent to Acquisition 0      
Land and Improvements 21,596      
Total 334,088      
Accumulated Depreciation $ 4,308      
Depreciable Lives (Years) [5] (1)      
680 Folsom Street | Office Building [Member]        
Original Cost        
Original Land $ 72,545      
Original Building 219,766      
Costs Capitalized Subsequent to Acquisition 8,026      
Land and Improvements 72,545      
Building and Improvements 227,792      
Total 300,337      
Accumulated Depreciation $ 72,414      
Depreciable Lives (Years) [5] (1)      
145 Broadway | Office Building [Member]        
Original Cost        
Original Land $ 121      
Original Building 273,013      
Costs Capitalized Subsequent to Acquisition 26,184      
Land and Improvements 23,367      
Building and Improvements 275,951      
Total 299,318      
Accumulated Depreciation $ 26,881      
Depreciable Lives (Years) [5] (1)      
2200 Pennsylvania Avenue | Office Building [Member]        
Original Cost        
Original Land $ 0      
Original Building 183,541      
Costs Capitalized Subsequent to Acquisition 113,108      
Land and Improvements 104,329      
Building and Improvements 192,320      
Total 296,649      
Accumulated Depreciation $ 71,410      
Depreciable Lives (Years) [5] (1)      
South of Market and Democracy Tower | Office Building [Member]        
Original Cost        
Original Land $ 13,603      
Original Building 237,479      
Costs Capitalized Subsequent to Acquisition 28,991      
Land and Improvements 13,687      
Building and Improvements 266,386      
Total 280,073      
Accumulated Depreciation $ 98,665      
Depreciable Lives (Years) [5] (1)      
Bay Colony Corporate Center | Office Building [Member]        
Original Cost        
Original Land $ 18,789      
Original Building 148,451      
Costs Capitalized Subsequent to Acquisition 87,804      
Land and Improvements 18,789      
Building and Improvements 231,828      
Land held for development 4,427      
Total 255,044      
Accumulated Depreciation $ 105,172      
Depreciable Lives (Years) [5] (1)      
535 Mission Street | Office Building [Member]        
Original Cost        
Original Land $ 40,933      
Original Building 148,378      
Costs Capitalized Subsequent to Acquisition 3,852      
Land and Improvements 40,934      
Building and Improvements 152,229      
Total 193,163      
Accumulated Depreciation $ 42,776      
Depreciable Lives (Years) [5] (1)      
Mountain View Research Park | Office Building [Member]        
Original Cost        
Original Land $ 95,066      
Original Building 68,373      
Costs Capitalized Subsequent to Acquisition 21,270      
Land and Improvements 95,066      
Building and Improvements 89,643      
Total 184,709      
Accumulated Depreciation $ 28,575      
Depreciable Lives (Years) [5] (1)      
Reservoir Place | Office Building [Member]        
Original Cost        
Original Land $ 18,605      
Original Building 104,124      
Costs Capitalized Subsequent to Acquisition 55,359      
Land and Improvements 20,108      
Building and Improvements 156,915      
Land held for development 1,065      
Total 178,088      
Accumulated Depreciation $ 85,394      
Depreciable Lives (Years) [5] (1)      
1330 Connecticut Avenue | Office Building [Member]        
Original Cost        
Original Land $ 25,982      
Original Building 82,311      
Costs Capitalized Subsequent to Acquisition 38,047      
Land and Improvements 27,135      
Building and Improvements 119,205      
Total 146,340      
Accumulated Depreciation $ 48,273      
Depreciable Lives (Years) [5] (1)      
One Freedom Square | Office Building [Member]        
Original Cost        
Original Land $ 9,929      
Original Building 84,504      
Costs Capitalized Subsequent to Acquisition 51,743      
Land and Improvements 11,293      
Building and Improvements 134,883      
Total 146,176      
Accumulated Depreciation $ 66,084      
Depreciable Lives (Years) [5] (1)      
880 Winter Street [Member] | Office Building [Member]        
Original Cost        
Original Land $ 15,597      
Original Building 37,255      
Costs Capitalized Subsequent to Acquisition 91,537      
Land and Improvements 15,597      
Building and Improvements 128,792      
Total 144,389      
Accumulated Depreciation $ 2,560      
Depreciable Lives (Years) [5] (1)      
Kingstowne Towne Center | Office Building [Member]        
Original Cost        
Original Land $ 18,021      
Original Building 109,038      
Costs Capitalized Subsequent to Acquisition 3,822      
Land and Improvements 18,062      
Building and Improvements 112,819      
Total 130,881      
Accumulated Depreciation $ 52,543      
Depreciable Lives (Years) [5] (1)      
140 Kendrick Street | Office Building [Member]        
Original Cost        
Original Land $ 18,095      
Original Building 66,905      
Costs Capitalized Subsequent to Acquisition 42,528      
Land and Improvements 19,092      
Building and Improvements 102,625      
Development and Construction in Progress 5,811      
Total 127,528      
Accumulated Depreciation $ 41,627      
Depreciable Lives (Years) [5] (1)      
Shady Grove Innovation District [Member] | Office Building [Member]        
Original Cost        
Original Land $ 52,030      
Original Building 64,212      
Costs Capitalized Subsequent to Acquisition 7,219      
Land and Improvements 26,834      
Building and Improvements 34,988      
Land held for development 61,639      
Total 123,461      
Accumulated Depreciation $ 3,319      
Depreciable Lives (Years) [5] (1)      
One and Two Reston Overlook | Office Building [Member]        
Original Cost        
Original Land $ 16,456      
Original Building 66,192      
Costs Capitalized Subsequent to Acquisition 40,516      
Land and Improvements 16,179      
Building and Improvements 106,985      
Total 123,164      
Accumulated Depreciation $ 57,631      
Depreciable Lives (Years) [5] (1)      
Weston Corporate Center | Office Building [Member]        
Original Cost        
Original Land $ 25,753      
Original Building 92,312      
Costs Capitalized Subsequent to Acquisition 968      
Land and Improvements 25,854      
Building and Improvements 93,179      
Total 119,033      
Accumulated Depreciation $ 38,385      
Depreciable Lives (Years) [5] (1)      
17Fifty Presidents Street | Office Building [Member]        
Original Cost        
Original Land $ 0      
Original Building 113,362      
Costs Capitalized Subsequent to Acquisition 162      
Land and Improvements 0      
Building and Improvements 113,524      
Total 113,524      
Accumulated Depreciation $ 12,232      
Depreciable Lives (Years) [5] (1)      
Discovery Square | Office Building [Member]        
Original Cost        
Original Land $ 11,198      
Original Building 71,782      
Costs Capitalized Subsequent to Acquisition 21,618      
Land and Improvements 12,533      
Building and Improvements 92,065      
Total 104,598      
Accumulated Depreciation $ 54,116      
Depreciable Lives (Years) [5] (1)      
355 Main Street | Office Building [Member]        
Original Cost        
Original Land $ 18,863      
Original Building 53,346      
Costs Capitalized Subsequent to Acquisition 25,418      
Land and Improvements 21,173      
Building and Improvements 76,454      
Total 97,627      
Accumulated Depreciation $ 34,399      
Depreciable Lives (Years) [5] (1)      
10 CityPoint | Office Building [Member]        
Original Cost        
Original Land $ 1,953      
Original Building 85,752      
Costs Capitalized Subsequent to Acquisition 6,406      
Land and Improvements 2,290      
Building and Improvements 91,821      
Total 94,111      
Accumulated Depreciation $ 20,616      
Depreciable Lives (Years) [5] (1)      
Two Freedom Square | Office Building [Member]        
Original Cost        
Original Land $ 13,930      
Original Building 77,739      
Costs Capitalized Subsequent to Acquisition 317      
Land and Improvements 15,420      
Building and Improvements 76,566      
Total 91,986      
Accumulated Depreciation $ 35,850      
Depreciable Lives (Years) [5] (1)      
200 West Street | Office Building [Member]        
Original Cost        
Original Land $ 16,148      
Original Building 24,983      
Costs Capitalized Subsequent to Acquisition 49,264      
Land and Improvements 16,813      
Building and Improvements 73,265      
Land held for development 317      
Total 90,395      
Accumulated Depreciation $ 23,428      
Depreciable Lives (Years) [5] (1)      
90 Broadway | Office Building [Member]        
Original Cost        
Original Land $ 19,104      
Original Building 52,078      
Costs Capitalized Subsequent to Acquisition 18,876      
Land and Improvements 20,785      
Building and Improvements 69,273      
Total 90,058      
Accumulated Depreciation $ 29,294      
Depreciable Lives (Years) [5] (1)      
153 & 211 Second Avenue [Member] | Office Building [Member]        
Original Cost        
Original Land $ 33,233      
Original Building 55,940      
Costs Capitalized Subsequent to Acquisition 202      
Land and Improvements 33,233      
Building and Improvements 55,940      
Land held for development 202      
Total 89,375      
Accumulated Depreciation $ 4,808      
Depreciable Lives (Years) [5] (1)      
230 CityPoint | Office Building [Member]        
Original Cost        
Original Land $ 13,189      
Original Building 49,823      
Costs Capitalized Subsequent to Acquisition 24,604      
Land and Improvements 13,807      
Building and Improvements 73,809      
Total 87,616      
Accumulated Depreciation $ 38,306      
Depreciable Lives (Years) [5] (1)      
20 Citypoint | Office Building [Member]        
Original Cost        
Original Land $ 4,887      
Original Building 72,764      
Costs Capitalized Subsequent to Acquisition 7,072      
Land and Improvements 4,887      
Building and Improvements 79,836      
Total 84,723      
Accumulated Depreciation $ 9,606      
Depreciable Lives (Years) [5] (1)      
Waltham Weston Corporate Center | Office Building [Member]        
Original Cost        
Original Land $ 10,385      
Original Building 60,694      
Costs Capitalized Subsequent to Acquisition 12,859      
Land and Improvements 11,097      
Building and Improvements 72,841      
Total 83,938      
Accumulated Depreciation $ 42,839      
Depreciable Lives (Years) [5] (1)      
77 CityPoint | Office Building [Member]        
Original Cost        
Original Land $ 13,847      
Original Building 60,383      
Costs Capitalized Subsequent to Acquisition 9,701      
Land and Improvements 14,023      
Building and Improvements 69,908      
Total 83,931      
Accumulated Depreciation $ 32,578      
Depreciable Lives (Years) [5] (1)      
Sumner Square | Office Building [Member]        
Original Cost        
Original Land $ 624      
Original Building 28,745      
Costs Capitalized Subsequent to Acquisition 49,302      
Land and Improvements 28,205      
Building and Improvements 50,466      
Total 78,671      
Accumulated Depreciation $ 31,436      
Depreciable Lives (Years) [5] (1)      
2440 West El Camino Real | Office Building [Member]        
Original Cost        
Original Land $ 16,741      
Original Building 51,285      
Costs Capitalized Subsequent to Acquisition 6,391      
Land and Improvements 16,741      
Building and Improvements 57,676      
Total 74,417      
Accumulated Depreciation $ 19,375      
Depreciable Lives (Years) [5] (1)      
300 Binney Street | Office Building [Member]        
Original Cost        
Original Land $ 18,080      
Original Building 51,262      
Costs Capitalized Subsequent to Acquisition 1,268      
Land and Improvements 18,080      
Building and Improvements 51,402      
Land held for development 1,128      
Total 70,610      
Accumulated Depreciation $ 18,995      
Depreciable Lives (Years) [5] (1)      
Reston Corporate Center | Office Building [Member]        
Original Cost        
Original Land $ 9,135      
Original Building 50,857      
Costs Capitalized Subsequent to Acquisition 5,579      
Land and Improvements 10,148      
Building and Improvements 55,423      
Total 65,571      
Accumulated Depreciation $ 33,822      
Depreciable Lives (Years) [5] (1)      
Wisconsin Place | Office Building [Member]        
Original Cost        
Original Land $ 0      
Original Building 53,349      
Costs Capitalized Subsequent to Acquisition 11,204      
Land and Improvements 0      
Building and Improvements 64,553      
Total 64,553      
Accumulated Depreciation $ 26,659      
Depreciable Lives (Years) [5] (1)      
255 Main Street | Office Building [Member]        
Original Cost        
Original Land $ 134      
Original Building 25,110      
Costs Capitalized Subsequent to Acquisition 33,597      
Land and Improvements 548      
Building and Improvements 58,293      
Total 58,841      
Accumulated Depreciation $ 42,204      
Depreciable Lives (Years) [5] (1)      
University Place | Office Building [Member]        
Original Cost        
Original Land $ 0      
Original Building 37,091      
Costs Capitalized Subsequent to Acquisition 15,903      
Land and Improvements 5,425      
Building and Improvements 47,569      
Total 52,994      
Accumulated Depreciation $ 35,296      
Depreciable Lives (Years) [5] (1)      
890 Winter Street | Office Building [Member]        
Original Cost        
Original Land $ 13,913      
Original Building 28,557      
Costs Capitalized Subsequent to Acquisition 6,998      
Land and Improvements 13,913      
Building and Improvements 35,555      
Total 49,468      
Accumulated Depreciation $ 5,409      
Depreciable Lives (Years) [5] (1)      
Capital Gallery | Office Building [Member]        
Original Cost        
Original Land $ 4,725      
Original Building 29,565      
Costs Capitalized Subsequent to Acquisition 9,544      
Land and Improvements 8,662      
Building and Improvements 35,172      
Total 43,834      
Accumulated Depreciation $ 22,415      
Depreciable Lives (Years) [5] (1)      
North First Business Park | Office Building [Member]        
Original Cost        
Original Land $ 23,398      
Original Building 13,069      
Costs Capitalized Subsequent to Acquisition 5,288      
Land and Improvements 23,378      
Building and Improvements 18,377      
Total 41,755      
Accumulated Depreciation $ 17,270      
Depreciable Lives (Years) [5] (1)      
150 Broadway | Office Building [Member]        
Original Cost        
Original Land $ 850      
Original Building 25,042      
Costs Capitalized Subsequent to Acquisition 15,726      
Land and Improvements 1,323      
Building and Improvements 40,295      
Total 41,618      
Accumulated Depreciation $ 16,841      
Depreciable Lives (Years) [5] (1)      
105 Broadway | Office Building [Member]        
Original Cost        
Original Land $ 1,299      
Original Building 12,943      
Costs Capitalized Subsequent to Acquisition 12,718      
Land and Improvements 2,390      
Building and Improvements 24,570      
Total 26,960      
Accumulated Depreciation $ 15,578      
Depreciable Lives (Years) [5] (1)      
Lexington Office Park | Office Building [Member]        
Original Cost        
Original Land $ 998      
Original Building 1,426      
Costs Capitalized Subsequent to Acquisition 19,842      
Land and Improvements 1,263      
Building and Improvements 19,551      
Land held for development 1,452      
Total 22,266      
Accumulated Depreciation $ 16,716      
Depreciable Lives (Years) [5] (1)      
The Point | Office Building [Member]        
Original Cost        
Original Land $ 6,395      
Original Building 10,040      
Costs Capitalized Subsequent to Acquisition 546      
Land and Improvements 6,492      
Building and Improvements 10,489      
Total 16,981      
Accumulated Depreciation $ 2,308      
Depreciable Lives (Years) [5] (1)      
690 Folsom Street | Office Building [Member]        
Original Cost        
Original Land $ 3,219      
Original Building 11,038      
Costs Capitalized Subsequent to Acquisition 1,877      
Land and Improvements 3,219      
Building and Improvements 12,915      
Total 16,134      
Accumulated Depreciation $ 3,838      
Depreciable Lives (Years) [5] (1)      
33 Hayden Avenue | Office Building [Member]        
Original Cost        
Original Land $ 266      
Original Building 3,234      
Costs Capitalized Subsequent to Acquisition 11,501      
Land and Improvements 425      
Building and Improvements 14,576      
Total 15,001      
Accumulated Depreciation $ 7,929      
Depreciable Lives (Years) [5] (1)      
The Avant Retail | Office Building [Member]        
Original Cost        
Original Land $ 1,499      
Original Building 6,647      
Costs Capitalized Subsequent to Acquisition 2,577      
Land and Improvements 1,499      
Building and Improvements 9,224      
Total 10,723      
Accumulated Depreciation $ 3,210      
Depreciable Lives (Years) [5] (1)      
92-100 Hayden Avenue | Office Building [Member]        
Original Cost        
Original Land $ 594      
Original Building 6,748      
Costs Capitalized Subsequent to Acquisition 2,297      
Land and Improvements 778      
Building and Improvements 8,861      
Total 9,639      
Accumulated Depreciation $ 7,507      
Depreciable Lives (Years) [5] (1)      
32 Hartwell Avenue | Office Building [Member]        
Original Cost        
Original Land $ 168      
Original Building 1,943      
Costs Capitalized Subsequent to Acquisition 6,944      
Land and Improvements 314      
Building and Improvements 8,741      
Total 9,055      
Accumulated Depreciation $ 3,103      
Depreciable Lives (Years) [5] (1)      
250 Binney Street | Office Building [Member]        
Original Cost        
Original Land $ 110      
Original Building 4,483      
Costs Capitalized Subsequent to Acquisition 3,593      
Land and Improvements 273      
Building and Improvements 7,913      
Total 8,186      
Accumulated Depreciation $ 6,974      
Depreciable Lives (Years) [5] (1)      
453 Ravendale Drive | Office Building [Member]        
Original Cost        
Original Land $ 5,477      
Original Building 1,090      
Costs Capitalized Subsequent to Acquisition 677      
Land and Improvements 5,477      
Building and Improvements 1,767      
Total 7,244      
Accumulated Depreciation $ 964      
Depreciable Lives (Years) [5] (1)      
17 Hartwell Avenue | Office Building [Member]        
Original Cost        
Original Land $ 26      
Original Building 150      
Costs Capitalized Subsequent to Acquisition 6,064      
Land and Improvements 65      
Building and Improvements 6,175      
Total 6,240      
Accumulated Depreciation $ 3,530      
Depreciable Lives (Years) [5] (1)      
The Skylyne | Residential Building        
Original Cost        
Original Land $ 28,962      
Original Building 239,077      
Costs Capitalized Subsequent to Acquisition 1,784      
Land and Improvements 28,962      
Building and Improvements 240,861      
Total 269,823      
Accumulated Depreciation $ 14,154      
Depreciable Lives (Years) [5] (1)      
Signature at Reston | Residential Building        
Original Cost        
Original Land $ 27,076      
Original Building 190,580      
Costs Capitalized Subsequent to Acquisition 1,667      
Land and Improvements 27,076      
Building and Improvements 192,247      
Total 219,323      
Accumulated Depreciation $ 23,353      
Depreciable Lives (Years) [5] (1)      
Proto Kendall Square | Residential Building        
Original Cost        
Original Land $ 9,243      
Original Building 127,248      
Costs Capitalized Subsequent to Acquisition 3,336      
Land and Improvements 9,245      
Building and Improvements 130,582      
Total 139,827      
Accumulated Depreciation $ 14,508      
Depreciable Lives (Years) [5] (1)      
The Lofts at Atlantic Wharf | Residential Building        
Original Cost        
Original Land $ 3,529      
Original Building 54,891      
Costs Capitalized Subsequent to Acquisition 2,356      
Land and Improvements 3,529      
Building and Improvements 57,247      
Total 60,776      
Accumulated Depreciation $ 17,174      
Depreciable Lives (Years) [5] (1)      
Boston Cambridge Marriott | Hotel [Member]        
Original Cost        
Original Land $ 478      
Original Building 37,918      
Costs Capitalized Subsequent to Acquisition 32,837      
Land and Improvements 1,201      
Building and Improvements 69,521      
Land held for development 511      
Total 71,233      
Accumulated Depreciation $ 51,568      
Depreciable Lives (Years) [5] (1)      
Kendall Center Green Garage | Garage        
Original Cost        
Original Land $ 0      
Original Building 35,035      
Costs Capitalized Subsequent to Acquisition 6,798      
Land and Improvements 103      
Building and Improvements 41,730      
Total 41,833      
Accumulated Depreciation $ 17,039      
Depreciable Lives (Years) [5] (1)      
Kendall Center Yellow Garage | Garage        
Original Cost        
Original Land $ 1,256      
Original Building 15,697      
Costs Capitalized Subsequent to Acquisition 1,653      
Land and Improvements 1,434      
Building and Improvements 17,172      
Total 18,606      
Accumulated Depreciation $ 7,395      
Depreciable Lives (Years) [5] (1)      
Kendall Center Blue Garage | Garage        
Original Cost        
Original Land $ 1,163      
Original Building 11,633      
Costs Capitalized Subsequent to Acquisition 2,111      
Land and Improvements 1,579      
Building and Improvements 13,328      
Total 14,907      
Accumulated Depreciation $ 13,075      
Depreciable Lives (Years) [5] (1)      
2100 Pennsylvania Avenue | Development        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 472,873      
Land and Improvements 185,203      
Building and Improvements 230,497      
Development and Construction in Progress 57,173      
Total 472,873      
Accumulated Depreciation $ 9,755      
Depreciable Lives (Years) N/A      
190 CityPoint (formerly 180 CityPoint) [Member] | Development        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 140,370      
Development and Construction in Progress 140,370      
Total $ 140,370      
Depreciable Lives (Years) N/A      
103 CityPoint | Development        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 44,752      
Land held for development 74      
Development and Construction in Progress 44,678      
Total $ 44,752      
Depreciable Lives (Years) N/A      
Reston Next Office Phase II | Development        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 22,954      
Development and Construction in Progress 22,954      
Total $ 22,954      
Depreciable Lives (Years) N/A      
Reston Next Retail | Development        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 3,199      
Development and Construction in Progress 3,199      
Total $ 3,199      
Depreciable Lives (Years) N/A      
777 Harrison Street | Land        
Original Cost        
Original Land $ 144,647      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 28,239      
Building and Improvements 47      
Land held for development 172,839      
Total 172,886      
Accumulated Depreciation $ 20      
Depreciable Lives (Years) N/A      
Kendall Center Master Plan | Land        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 148,476      
Land held for development 148,476      
Total $ 148,476      
Depreciable Lives (Years) N/A      
Back Bay Station Master Plan | Land        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 72,957      
Land held for development 72,957      
Total $ 72,957      
Depreciable Lives (Years) N/A      
3625 - 3635 Peterson Way | Land        
Original Cost        
Original Land $ 63,206      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 5,165      
Land held for development 68,371      
Total $ 68,371      
Depreciable Lives (Years) N/A      
North First Master Plan | Land        
Original Cost        
Original Land $ 35,004      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 3,968      
Land held for development 38,972      
Total $ 38,972      
Depreciable Lives (Years) N/A      
Plaza at Almaden | Land        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 38,090      
Land held for development 38,090      
Total $ 38,090      
Depreciable Lives (Years) N/A      
Springfield Metro Center | Land        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 19,891      
Land held for development 19,891      
Total $ 19,891      
Depreciable Lives (Years) N/A      
CityPoint South Master Plan | Land        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 19,693      
Land held for development 19,693      
Total $ 19,693      
Depreciable Lives (Years) N/A      
Reston Gateway Master Plan | Land        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 12,734      
Land held for development 12,734      
Total $ 12,734      
Depreciable Lives (Years) N/A      
Weston Quarry | Land        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 1,249      
Land held for development 1,249      
Total $ 1,249      
Depreciable Lives (Years) N/A      
Broad Run Business Park | Land        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 1,184      
Land held for development 1,184      
Total $ 1,184      
Depreciable Lives (Years) N/A      
Reston Overlook Master Plan | Land        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 80      
Land held for development 80      
Total $ 80      
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] $ 3,272,368      
Original Cost        
Original Land 5,373,987      
Original Building 14,755,092      
Costs Capitalized Subsequent to Acquisition 5,247,621      
Land and Improvements [7] 5,476,618      
Building and Improvements [8] 18,772,007      
Land held for development [4] 721,501 560,355    
Development and Construction in Progress 406,574 894,172    
Total 25,376,700 23,734,833 22,926,494 22,449,476
Accumulated Depreciation 6,143,384 5,736,240 $ 5,396,111 $ 5,135,289
Furniture, Fixtures and Equipment 50,310 51,695    
Aggregate cost for tax purpose 25,700,000      
Real Estate Aggregate Accumulated Depreciation For Tax Purposes 5,600,000      
Debt Issuance Costs, Net 27,632      
Right-of-use assets - finance leases 237,510 237,507    
Right of use assets - operating leases $ 167,351 $ 169,778    
Boston Properties Limited Partnership | Maximum [Member]        
Original Cost        
Real Estate and Accumulated Depreciation, Life Used for Depreciation 40 years      
Boston Properties Limited Partnership | Furniture, fixtures, and equipment        
Original Cost        
Accumulated Depreciation Related to Furniture, Fixtures and Equipment $ 37,090      
Boston Properties Limited Partnership | Land and Land Improvements [Member]        
Original Cost        
Right-of-use assets - finance leases 214,165      
Right of use assets - operating leases 167,351      
Boston Properties Limited Partnership | Buildings and improvements        
Original Cost        
Right-of-use assets - finance leases 23,345      
Boston Properties Limited Partnership | 767Fifth Avenue (the General Motors Building) | Office Building [Member]        
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]        
Encumbrances 2,284,510      
Original Cost        
Original Land 1,796,252      
Original Building 1,532,654      
Costs Capitalized Subsequent to Acquisition 325,762      
Land and Improvements 1,796,252      
Building and Improvements 1,858,416      
Total 3,654,668      
Accumulated Depreciation $ 457,344      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Prudential Center | Office Building [Member]        
Original Cost        
Original Land $ 92,077      
Original Building 948,357      
Costs Capitalized Subsequent to Acquisition 658,972      
Land and Improvements 100,541      
Building and Improvements 1,466,876      
Land held for development 231      
Development and Construction in Progress 131,758      
Total 1,699,406      
Accumulated Depreciation $ 702,725      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Embarcadero Center | Office Building [Member]        
Original Cost        
Original Land $ 179,697      
Original Building 847,410      
Costs Capitalized Subsequent to Acquisition 437,070      
Land and Improvements 180,419      
Building and Improvements 1,283,758      
Total 1,464,177      
Accumulated Depreciation $ 716,657      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 399 Park Avenue | Office Building [Member]        
Original Cost        
Original Land $ 339,200      
Original Building 700,358      
Costs Capitalized Subsequent to Acquisition 334,213      
Land and Improvements 339,200      
Building and Improvements 1,034,571      
Total 1,373,771      
Accumulated Depreciation $ 426,148      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 601 Lexington Avenue | Office Building [Member]        
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]        
Encumbrances $ 987,858      
Original Cost        
Original Land 241,600      
Original Building 494,782      
Costs Capitalized Subsequent to Acquisition 478,558      
Land and Improvements 279,281      
Building and Improvements 935,659      
Total 1,214,940      
Accumulated Depreciation $ 337,421      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Salesforce Tower | Office Building [Member]        
Original Cost        
Original Land $ 200,349      
Original Building 946,205      
Costs Capitalized Subsequent to Acquisition 7,462      
Land and Improvements 200,349      
Building and Improvements 953,667      
Total 1,154,016      
Accumulated Depreciation $ 129,281      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 200 Clarendon Street and Garage | Office Building [Member]        
Original Cost        
Original Land $ 219,543      
Original Building 667,884      
Costs Capitalized Subsequent to Acquisition 235,129      
Land and Improvements 250,512      
Building and Improvements 872,044      
Total 1,122,556      
Accumulated Depreciation $ 310,318      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 250 West 55th Street | Office Building [Member]        
Original Cost        
Original Land $ 285,263      
Original Building 603,167      
Costs Capitalized Subsequent to Acquisition 51,800      
Land and Improvements 285,263      
Building and Improvements 654,967      
Total 940,230      
Accumulated Depreciation $ 179,143      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 100 Federal Street | Office Building [Member]        
Original Cost        
Original Land $ 131,067      
Original Building 435,954      
Costs Capitalized Subsequent to Acquisition 119,341      
Land and Improvements 131,067      
Building and Improvements 555,295      
Total 686,362      
Accumulated Depreciation $ 157,368      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Madison Centre | Office Building [Member]        
Original Cost        
Original Land $ 104,641      
Original Building 564,336      
Costs Capitalized Subsequent to Acquisition 2,879      
Land and Improvements 104,641      
Building and Improvements 567,215      
Total 671,856      
Accumulated Depreciation $ 13,611      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Times Square Tower | Office Building [Member]        
Original Cost        
Original Land $ 165,413      
Original Building 380,438      
Costs Capitalized Subsequent to Acquisition 83,458      
Land and Improvements 159,694      
Building and Improvements 469,615      
Total 629,309      
Accumulated Depreciation $ 229,310      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Carnegie Center | Office Building [Member]        
Original Cost        
Original Land $ 142,666      
Original Building 316,856      
Costs Capitalized Subsequent to Acquisition 153,298      
Land and Improvements 90,501      
Building and Improvements 465,769      
Land held for development 55,919      
Development and Construction in Progress 631      
Total 612,820      
Accumulated Depreciation $ 247,525      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 125 Broadway | Office Building [Member]        
Original Cost        
Original Land $ 126,364      
Original Building 433,662      
Costs Capitalized Subsequent to Acquisition 58      
Land and Improvements 126,364      
Building and Improvements 433,720      
Total 560,084      
Accumulated Depreciation $ 4,503      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Atlantic Wharf | Office Building [Member]        
Original Cost        
Original Land $ 63,988      
Original Building 454,537      
Costs Capitalized Subsequent to Acquisition 24,158      
Land and Improvements 63,988      
Building and Improvements 478,695      
Total 542,683      
Accumulated Depreciation $ 171,876      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Reston Next | Development        
Original Cost        
Original Land $ 2,901      
Original Building 525,277      
Costs Capitalized Subsequent to Acquisition 0      
Land and Improvements 2,901      
Building and Improvements 525,277      
Total 528,178      
Accumulated Depreciation $ 15,293      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 599 Lexington Avenue | Office Building [Member]        
Original Cost        
Original Land $ 81,040      
Original Building 100,507      
Costs Capitalized Subsequent to Acquisition 218,367      
Land and Improvements 81,040      
Building and Improvements 318,874      
Total 399,914      
Accumulated Depreciation $ 173,396      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Fountain Square | Office Building [Member]        
Original Cost        
Original Land $ 56,853      
Original Building 306,298      
Costs Capitalized Subsequent to Acquisition 39,288      
Land and Improvements 56,853      
Building and Improvements 345,586      
Total 402,439      
Accumulated Depreciation $ 104,864      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 510 Madison Avenue | Office Building [Member]        
Original Cost        
Original Land $ 103,000      
Original Building 253,665      
Costs Capitalized Subsequent to Acquisition 31,682      
Land and Improvements 103,000      
Building and Improvements 285,347      
Total 388,347      
Accumulated Depreciation $ 95,520      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 325 Main Street | Development        
Original Cost        
Original Land $ 21,596      
Original Building 312,492      
Costs Capitalized Subsequent to Acquisition (193)      
Land and Improvements 21,403      
Building and Improvements 312,492      
Total 333,895      
Accumulated Depreciation $ 4,308      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 680 Folsom Street | Office Building [Member]        
Original Cost        
Original Land $ 72,545      
Original Building 219,766      
Costs Capitalized Subsequent to Acquisition 8,026      
Land and Improvements 72,545      
Building and Improvements 227,792      
Total 300,337      
Accumulated Depreciation $ 72,414      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 145 Broadway | Office Building [Member]        
Original Cost        
Original Land $ 121      
Original Building 273,013      
Costs Capitalized Subsequent to Acquisition 25,981      
Land and Improvements 23,164      
Building and Improvements 275,951      
Total 299,115      
Accumulated Depreciation $ 26,881      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 2200 Pennsylvania Avenue | Office Building [Member]        
Original Cost        
Original Land $ 0      
Original Building 183,541      
Costs Capitalized Subsequent to Acquisition 113,108      
Land and Improvements 104,329      
Building and Improvements 192,320      
Total 296,649      
Accumulated Depreciation $ 71,410      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | South of Market and Democracy Tower | Office Building [Member]        
Original Cost        
Original Land $ 13,603      
Original Building 237,479      
Costs Capitalized Subsequent to Acquisition 28,655      
Land and Improvements 13,603      
Building and Improvements 266,134      
Total 279,737      
Accumulated Depreciation $ 98,574      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Bay Colony Corporate Center | Office Building [Member]        
Original Cost        
Original Land $ 18,789      
Original Building 148,451      
Costs Capitalized Subsequent to Acquisition 87,804      
Land and Improvements 18,789      
Building and Improvements 231,828      
Land held for development 4,427      
Total 255,044      
Accumulated Depreciation $ 105,172      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 535 Mission Street | Office Building [Member]        
Original Cost        
Original Land $ 40,933      
Original Building 148,378      
Costs Capitalized Subsequent to Acquisition 3,852      
Land and Improvements 40,934      
Building and Improvements 152,229      
Total 193,163      
Accumulated Depreciation $ 42,776      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Mountain View Research Park | Office Building [Member]        
Original Cost        
Original Land $ 95,066      
Original Building 68,373      
Costs Capitalized Subsequent to Acquisition 21,270      
Land and Improvements 95,066      
Building and Improvements 89,643      
Total 184,709      
Accumulated Depreciation $ 28,575      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Reservoir Place | Office Building [Member]        
Original Cost        
Original Land $ 18,605      
Original Building 104,124      
Costs Capitalized Subsequent to Acquisition 51,284      
Land and Improvements 19,089      
Building and Improvements 153,859      
Land held for development 1,065      
Total 174,013      
Accumulated Depreciation $ 84,089      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 1330 Connecticut Avenue | Office Building [Member]        
Original Cost        
Original Land $ 25,982      
Original Building 82,311      
Costs Capitalized Subsequent to Acquisition 33,434      
Land and Improvements 25,982      
Building and Improvements 115,745      
Total 141,727      
Accumulated Depreciation $ 46,795      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | One Freedom Square | Office Building [Member]        
Original Cost        
Original Land $ 9,929      
Original Building 84,504      
Costs Capitalized Subsequent to Acquisition 46,106      
Land and Improvements 9,883      
Building and Improvements 130,656      
Total 140,539      
Accumulated Depreciation $ 64,278      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 880 Winter Street [Member] | Development        
Original Cost        
Original Land $ 15,597      
Original Building 37,255      
Costs Capitalized Subsequent to Acquisition 91,537      
Land and Improvements 15,597      
Building and Improvements 128,792      
Total 144,389      
Accumulated Depreciation $ 2,560      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Kingstowne Towne Center | Office Building [Member]        
Original Cost        
Original Land $ 18,021      
Original Building 109,038      
Costs Capitalized Subsequent to Acquisition 3,658      
Land and Improvements 18,021      
Building and Improvements 112,696      
Total 130,717      
Accumulated Depreciation $ 52,498      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 140 Kendrick Street | Office Building [Member]        
Original Cost        
Original Land $ 18,095      
Original Building 66,905      
Costs Capitalized Subsequent to Acquisition 38,538      
Land and Improvements 18,095      
Building and Improvements 99,632      
Development and Construction in Progress 5,811      
Total 123,538      
Accumulated Depreciation $ 40,368      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Shady Grove Innovation District [Member] | Office Building [Member]        
Original Cost        
Original Land $ 52,030      
Original Building 64,212      
Costs Capitalized Subsequent to Acquisition 7,219      
Land and Improvements 26,834      
Building and Improvements 34,988      
Land held for development 61,639      
Total 123,461      
Accumulated Depreciation $ 3,319      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | One and Two Reston Overlook | Office Building [Member]        
Original Cost        
Original Land $ 16,456      
Original Building 66,192      
Costs Capitalized Subsequent to Acquisition 36,098      
Land and Improvements 15,074      
Building and Improvements 103,672      
Total 118,746      
Accumulated Depreciation $ 56,216      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Weston Corporate Center | Office Building [Member]        
Original Cost        
Original Land $ 25,753      
Original Building 92,312      
Costs Capitalized Subsequent to Acquisition 968      
Land and Improvements 25,854      
Building and Improvements 93,179      
Total 119,033      
Accumulated Depreciation $ 38,385      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 17Fifty Presidents Street | Office Building [Member]        
Original Cost        
Original Land $ 0      
Original Building 113,362      
Costs Capitalized Subsequent to Acquisition 162      
Land and Improvements 0      
Building and Improvements 113,524      
Total 113,524      
Accumulated Depreciation $ 12,232      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Discovery Square | Office Building [Member]        
Original Cost        
Original Land $ 11,198      
Original Building 71,782      
Costs Capitalized Subsequent to Acquisition 16,073      
Land and Improvements 11,146      
Building and Improvements 87,907      
Total 99,053      
Accumulated Depreciation $ 52,341      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 355 Main Street | Office Building [Member]        
Original Cost        
Original Land $ 18,863      
Original Building 53,346      
Costs Capitalized Subsequent to Acquisition 25,120      
Land and Improvements 21,098      
Building and Improvements 76,231      
Total 97,329      
Accumulated Depreciation $ 34,306      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 10 CityPoint | Office Building [Member]        
Original Cost        
Original Land $ 1,953      
Original Building 85,752      
Costs Capitalized Subsequent to Acquisition 6,243      
Land and Improvements 2,127      
Building and Improvements 91,821      
Total 93,948      
Accumulated Depreciation $ 20,616      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Two Freedom Square | Office Building [Member]        
Original Cost        
Original Land $ 13,930      
Original Building 77,739      
Costs Capitalized Subsequent to Acquisition (5,895)      
Land and Improvements 13,866      
Building and Improvements 71,908      
Total 85,774      
Accumulated Depreciation $ 33,860      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 200 West Street | Office Building [Member]        
Original Cost        
Original Land $ 16,148      
Original Building 24,983      
Costs Capitalized Subsequent to Acquisition 46,603      
Land and Improvements 16,148      
Building and Improvements 71,269      
Land held for development 317      
Total 87,734      
Accumulated Depreciation $ 22,576      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 90 Broadway | Office Building [Member]        
Original Cost        
Original Land $ 19,104      
Original Building 52,078      
Costs Capitalized Subsequent to Acquisition 18,697      
Land and Improvements 20,741      
Building and Improvements 69,138      
Total 89,879      
Accumulated Depreciation $ 29,243      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 153 & 211 Second Avenue [Member] | Office Building [Member]        
Original Cost        
Original Land $ 33,233      
Original Building 55,940      
Costs Capitalized Subsequent to Acquisition 202      
Land and Improvements 33,233      
Building and Improvements 55,940      
Land held for development 202      
Total 89,375      
Accumulated Depreciation $ 4,808      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 230 CityPoint | Office Building [Member]        
Original Cost        
Original Land $ 13,189      
Original Building 49,823      
Costs Capitalized Subsequent to Acquisition 22,987      
Land and Improvements 13,403      
Building and Improvements 72,596      
Total 85,999      
Accumulated Depreciation $ 37,791      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 20 Citypoint | Office Building [Member]        
Original Cost        
Original Land $ 4,887      
Original Building 72,764      
Costs Capitalized Subsequent to Acquisition 7,072      
Land and Improvements 4,887      
Building and Improvements 79,836      
Total 84,723      
Accumulated Depreciation $ 9,606      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Waltham Weston Corporate Center | Office Building [Member]        
Original Cost        
Original Land $ 10,385      
Original Building 60,694      
Costs Capitalized Subsequent to Acquisition 9,872      
Land and Improvements 10,350      
Building and Improvements 70,601      
Total 80,951      
Accumulated Depreciation $ 41,883      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 77 CityPoint | Office Building [Member]        
Original Cost        
Original Land $ 13,847      
Original Building 60,383      
Costs Capitalized Subsequent to Acquisition 9,596      
Land and Improvements 13,997      
Building and Improvements 69,829      
Total 83,826      
Accumulated Depreciation $ 32,548      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Sumner Square | Office Building [Member]        
Original Cost        
Original Land $ 624      
Original Building 28,745      
Costs Capitalized Subsequent to Acquisition 47,222      
Land and Improvements 27,685      
Building and Improvements 48,906      
Total 76,591      
Accumulated Depreciation $ 30,773      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 2440 West El Camino Real | Office Building [Member]        
Original Cost        
Original Land $ 16,741      
Original Building 51,285      
Costs Capitalized Subsequent to Acquisition 6,391      
Land and Improvements 16,741      
Building and Improvements 57,676      
Total 74,417      
Accumulated Depreciation $ 19,375      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 300 Binney Street | Office Building [Member]        
Original Cost        
Original Land $ 18,080      
Original Building 51,262      
Costs Capitalized Subsequent to Acquisition 1,268      
Land and Improvements 18,080      
Building and Improvements 51,402      
Land held for development 1,128      
Total 70,610      
Accumulated Depreciation $ 18,995      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Reston Corporate Center | Office Building [Member]        
Original Cost        
Original Land $ 9,135      
Original Building 50,857      
Costs Capitalized Subsequent to Acquisition 2,968      
Land and Improvements 9,496      
Building and Improvements 53,464      
Total 62,960      
Accumulated Depreciation $ 32,986      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Wisconsin Place | Office Building [Member]        
Original Cost        
Original Land $ 0      
Original Building 53,349      
Costs Capitalized Subsequent to Acquisition 11,204      
Land and Improvements 0      
Building and Improvements 64,553      
Total 64,553      
Accumulated Depreciation $ 26,659      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 255 Main Street | Office Building [Member]        
Original Cost        
Original Land $ 134      
Original Building 25,110      
Costs Capitalized Subsequent to Acquisition 31,941      
Land and Improvements 134      
Building and Improvements 57,051      
Total 57,185      
Accumulated Depreciation $ 41,677      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | University Place | Office Building [Member]        
Original Cost        
Original Land $ 0      
Original Building 37,091      
Costs Capitalized Subsequent to Acquisition 14,453      
Land and Improvements 5,425      
Building and Improvements 46,119      
Total 51,544      
Accumulated Depreciation $ 34,270      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 890 Winter Street | Office Building [Member]        
Original Cost        
Original Land $ 13,913      
Original Building 28,557      
Costs Capitalized Subsequent to Acquisition 6,998      
Land and Improvements 13,913      
Building and Improvements 35,555      
Total 49,468      
Accumulated Depreciation $ 5,409      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Capital Gallery | Office Building [Member]        
Original Cost        
Original Land $ 4,725      
Original Building 29,565      
Costs Capitalized Subsequent to Acquisition 4,882      
Land and Improvements 6,128      
Building and Improvements 33,044      
Total 39,172      
Accumulated Depreciation $ 21,506      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | North First Business Park | Office Building [Member]        
Original Cost        
Original Land $ 23,398      
Original Building 13,069      
Costs Capitalized Subsequent to Acquisition 5,265      
Land and Improvements 23,372      
Building and Improvements 18,360      
Total 41,732      
Accumulated Depreciation $ 17,264      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 150 Broadway | Office Building [Member]        
Original Cost        
Original Land $ 850      
Original Building 25,042      
Costs Capitalized Subsequent to Acquisition 13,721      
Land and Improvements 822      
Building and Improvements 38,791      
Total 39,613      
Accumulated Depreciation $ 16,195      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 105 Broadway | Office Building [Member]        
Original Cost        
Original Land $ 1,299      
Original Building 12,943      
Costs Capitalized Subsequent to Acquisition 10,611      
Land and Improvements 1,862      
Building and Improvements 22,991      
Total 24,853      
Accumulated Depreciation $ 14,898      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Lexington Office Park | Office Building [Member]        
Original Cost        
Original Land $ 998      
Original Building 1,426      
Costs Capitalized Subsequent to Acquisition 19,078      
Land and Improvements 1,072      
Building and Improvements 18,978      
Land held for development 1,452      
Total 21,502      
Accumulated Depreciation $ 16,474      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | The Point | Office Building [Member]        
Original Cost        
Original Land $ 6,395      
Original Building 10,040      
Costs Capitalized Subsequent to Acquisition 546      
Land and Improvements 6,492      
Building and Improvements 10,489      
Total 16,981      
Accumulated Depreciation $ 2,308      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 690 Folsom Street | Office Building [Member]        
Original Cost        
Original Land $ 3,219      
Original Building 11,038      
Costs Capitalized Subsequent to Acquisition 1,877      
Land and Improvements 3,219      
Building and Improvements 12,915      
Total 16,134      
Accumulated Depreciation $ 3,838      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 33 Hayden Avenue | Office Building [Member]        
Original Cost        
Original Land $ 266      
Original Building 3,234      
Costs Capitalized Subsequent to Acquisition 10,864      
Land and Improvements 266      
Building and Improvements 14,098      
Total 14,364      
Accumulated Depreciation $ 7,725      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | The Avant Retail | Office Building [Member]        
Original Cost        
Original Land $ 1,499      
Original Building 6,647      
Costs Capitalized Subsequent to Acquisition 2,577      
Land and Improvements 1,499      
Building and Improvements 9,224      
Total 10,723      
Accumulated Depreciation $ 3,210      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 92-100 Hayden Avenue | Office Building [Member]        
Original Cost        
Original Land $ 594      
Original Building 6,748      
Costs Capitalized Subsequent to Acquisition 1,568      
Land and Improvements 595      
Building and Improvements 8,315      
Total 8,910      
Accumulated Depreciation $ 7,273      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 32 Hartwell Avenue | Office Building [Member]        
Original Cost        
Original Land $ 168      
Original Building 1,943      
Costs Capitalized Subsequent to Acquisition 6,358      
Land and Improvements 168      
Building and Improvements 8,301      
Total 8,469      
Accumulated Depreciation $ 2,915      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 250 Binney Street | Office Building [Member]        
Original Cost        
Original Land $ 110      
Original Building 4,483      
Costs Capitalized Subsequent to Acquisition 2,939      
Land and Improvements 110      
Building and Improvements 7,422      
Total 7,532      
Accumulated Depreciation $ 6,769      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 453 Ravendale Drive | Office Building [Member]        
Original Cost        
Original Land $ 5,477      
Original Building 1,090      
Costs Capitalized Subsequent to Acquisition 677      
Land and Improvements 5,477      
Building and Improvements 1,767      
Total 7,244      
Accumulated Depreciation $ 964      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 17 Hartwell Avenue | Office Building [Member]        
Original Cost        
Original Land $ 26      
Original Building 150      
Costs Capitalized Subsequent to Acquisition 5,907      
Land and Improvements 26      
Building and Improvements 6,057      
Total 6,083      
Accumulated Depreciation $ 3,479      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | The Skylyne | Residential Building        
Original Cost        
Original Land $ 28,962      
Original Building 239,077      
Costs Capitalized Subsequent to Acquisition 1,784      
Land and Improvements 28,962      
Building and Improvements 240,861      
Total 269,823      
Accumulated Depreciation $ 14,154      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Signature at Reston | Residential Building        
Original Cost        
Original Land $ 27,076      
Original Building 190,580      
Costs Capitalized Subsequent to Acquisition 1,667      
Land and Improvements 27,076      
Building and Improvements 192,247      
Total 219,323      
Accumulated Depreciation $ 23,353      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Proto Kendall Square | Residential Building        
Original Cost        
Original Land $ 9,243      
Original Building 127,248      
Costs Capitalized Subsequent to Acquisition 3,336      
Land and Improvements 9,245      
Building and Improvements 130,582      
Total 139,827      
Accumulated Depreciation $ 14,508      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | The Lofts at Atlantic Wharf | Residential Building        
Original Cost        
Original Land $ 3,529      
Original Building 54,891      
Costs Capitalized Subsequent to Acquisition 2,356      
Land and Improvements 3,529      
Building and Improvements 57,247      
Total 60,776      
Accumulated Depreciation $ 17,174      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Boston Cambridge Marriott | Hotel [Member]        
Original Cost        
Original Land $ 478      
Original Building 37,918      
Costs Capitalized Subsequent to Acquisition 29,946      
Land and Improvements 478      
Building and Improvements 67,353      
Land held for development 511      
Total 68,342      
Accumulated Depreciation $ 50,642      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Kendall Center Green Garage | Garage        
Original Cost        
Original Land $ 0      
Original Building 35,035      
Costs Capitalized Subsequent to Acquisition 6,384      
Building and Improvements 41,419      
Total 41,419      
Accumulated Depreciation $ 16,909      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Kendall Center Yellow Garage | Garage        
Original Cost        
Original Land $ 1,256      
Original Building 15,697      
Costs Capitalized Subsequent to Acquisition 941      
Land and Improvements 1,256      
Building and Improvements 16,638      
Total 17,894      
Accumulated Depreciation $ 7,170      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | Kendall Center Blue Garage | Garage        
Original Cost        
Original Land $ 1,163      
Original Building 11,633      
Costs Capitalized Subsequent to Acquisition 446      
Land and Improvements 1,163      
Building and Improvements 12,079      
Total 13,242      
Accumulated Depreciation $ 12,006      
Depreciable Lives (Years) [9] (1)      
Boston Properties Limited Partnership | 2100 Pennsylvania Avenue | Development        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 472,873      
Land and Improvements 185,203      
Building and Improvements 230,497      
Development and Construction in Progress 57,173      
Total 472,873      
Accumulated Depreciation $ 9,755      
Depreciable Lives (Years) N/A      
Boston Properties Limited Partnership | 190 CityPoint (formerly 180 CityPoint) [Member] | Development        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 140,370      
Development and Construction in Progress 140,370      
Total 140,370      
Accumulated Depreciation $ 0      
Depreciable Lives (Years) N/A      
Boston Properties Limited Partnership | 103 CityPoint | Development        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 44,752      
Land held for development 74      
Development and Construction in Progress 44,678      
Total 44,752      
Accumulated Depreciation $ 0      
Depreciable Lives (Years) N/A      
Boston Properties Limited Partnership | Reston Next Office Phase II | Development        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 22,954      
Development and Construction in Progress 22,954      
Total 22,954      
Accumulated Depreciation $ 0      
Depreciable Lives (Years) N/A      
Boston Properties Limited Partnership | Reston Next Retail | Development        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 3,199      
Development and Construction in Progress 3,199      
Total 3,199      
Accumulated Depreciation $ 0      
Depreciable Lives (Years) N/A      
Boston Properties Limited Partnership | 777 Harrison Street | Land        
Original Cost        
Original Land $ 144,647      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 28,239      
Building and Improvements 47      
Land held for development 172,839      
Total 172,886      
Accumulated Depreciation $ 20      
Depreciable Lives (Years) N/A      
Boston Properties Limited Partnership | Kendall Center Master Plan | Land        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 148,476      
Land held for development 148,476      
Total 148,476      
Accumulated Depreciation $ 0      
Depreciable Lives (Years) N/A      
Boston Properties Limited Partnership | Back Bay Station Master Plan | Land        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 72,957      
Land held for development 72,957      
Total 72,957      
Accumulated Depreciation $ 0      
Depreciable Lives (Years) N/A      
Boston Properties Limited Partnership | 3625 - 3635 Peterson Way | Land        
Original Cost        
Original Land $ 63,206      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 5,165      
Land held for development 68,371      
Total 68,371      
Accumulated Depreciation $ 0      
Depreciable Lives (Years) N/A      
Boston Properties Limited Partnership | North First Master Plan | Land        
Original Cost        
Original Land $ 35,004      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 3,968      
Land held for development 38,972      
Total 38,972      
Accumulated Depreciation $ 0      
Depreciable Lives (Years) N/A      
Boston Properties Limited Partnership | Plaza at Almaden | Land        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 38,090      
Land held for development 38,090      
Total 38,090      
Accumulated Depreciation $ 0      
Depreciable Lives (Years) N/A      
Boston Properties Limited Partnership | Springfield Metro Center | Land        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 19,891      
Land held for development 19,891      
Total 19,891      
Accumulated Depreciation $ 0      
Depreciable Lives (Years) N/A      
Boston Properties Limited Partnership | CityPoint South Master Plan | Land        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 19,693      
Land held for development 19,693      
Total 19,693      
Accumulated Depreciation $ 0      
Depreciable Lives (Years) N/A      
Boston Properties Limited Partnership | Reston Gateway Master Plan | Land        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 12,734      
Land held for development 12,734      
Total 12,734      
Accumulated Depreciation $ 0      
Depreciable Lives (Years) N/A      
Boston Properties Limited Partnership | Weston Quarry | Land        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 1,249      
Land held for development 1,249      
Total 1,249      
Accumulated Depreciation $ 0      
Depreciable Lives (Years) N/A      
Boston Properties Limited Partnership | Broad Run Business Park | Land        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 1,184      
Land held for development 1,184      
Total 1,184      
Accumulated Depreciation $ 0      
Depreciable Lives (Years) N/A      
Boston Properties Limited Partnership | Reston Overlook Master Plan | Land        
Original Cost        
Original Land $ 0      
Original Building 0      
Costs Capitalized Subsequent to Acquisition 80      
Land held for development 80      
Total 80      
Accumulated Depreciation $ 0      
Depreciable Lives (Years) N/A      
[1] Includes unamortized deferred financing costs totaling approximately $27,632.
[2] Includes Right of Use Assets - Finance Leases and Right of Use Assets - Operating Leases of approximately $214,165 and $167,351, respectively.
[3] Includes Right of Use Assets - Finance Leases of approximately $23,345.
[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 $27,632.
[7] Includes Right of Use Assets - Finance Leases and Right of Use Assets - Operating Leases of approximately $214,165 and $167,351, respectively.
[8] Includes Right of Use Assets - Finance Leases of approximately $23,345.
[9] Depreciation of the buildings and improvements are calculated over lives ranging from the life of the lease to 40 years.