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Real Estate and Accumulated Depreciation Activity of Real Estate and Accumulated Depreciation (BPLP) (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Real Estate, Balance at the beginning of the year $ 21,605,545 $ 21,058,714 $ 20,114,576
Real Estate, Additions to / improvements of real estate 1,671,898 1,043,379 1,099,286
Real Estate, Assets sold / written off (432,746) (496,548) (155,148)
Real Estate, Balance at the end of the year 22,844,697 21,605,545 21,058,714
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Accumulated depreciation, Balance at beginning of the year 4,871,102 4,566,570 4,201,891
Accumulated depreciation, Depreciation expense 564,938 533,342 497,059
Accumulated depreciation, Assets sold / written off (196,861) (228,810) (132,380)
Accumulated depreciation, Balance at end of the year 5,239,179 4,871,102 4,566,570
Boston Properties Limited Partnership      
Reconciliation of Carrying Amount of Real Estate Investments [Roll Forward]      
Real Estate, Balance at the beginning of the year 21,207,189 20,647,236 19,701,185
Real Estate, Additions to / improvements of real estate 1,671,898 1,043,379 1,099,286
Real Estate, Assets sold / written off (429,611) (483,426) (153,235)
Real Estate, Balance at the end of the year 22,449,476 21,207,189 20,647,236
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]      
Accumulated depreciation, Balance at beginning of the year 4,773,800 4,473,895 4,116,020
Accumulated depreciation, Depreciation expense 557,130 525,584 488,919
Accumulated depreciation, Assets sold / written off (195,641) (225,679) (131,044)
Accumulated depreciation, Balance at end of the year $ 5,135,289 $ 4,773,800 $ 4,473,895