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Consolidated Statements of Capital and Noncontrolling Interests - USD ($) | 3 Months Ended | 9 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018 | Jun. 30, 2019 | Dec. 31, 2018 | Jun. 30, 2018 | Dec. 31, 2017
Common Stock, Shares, Outstanding | 154,572,073 |  | 154,572,073 |  |  | 154,458,478 |  |
Cumulative effect of a change in accounting principle |  |  | $ (4,379,000) | $ 5,496,000 |  |  |  |
Effective portion of interest rate contracts | $ (2,253,000) | $ 1,325,000 | (9,307,000) | 1,325,000 |  |  |  |
Amortization of interest rate contracts | 1,666,000 | 1,666,000 | 4,998,000 | 4,998,000 |  |  |  |
Acquisition of noncontrolling interest in property partnership | 43,000 |  | (186,963,000) |  |  |  |  |
sale of an interest in property partnerships | 0 |  | 0 |  |  |  |  |
Contributions from noncontrolling interests in property partnerships | 14,820,000 | 9,616,000 | 26,968,000 | 37,148,000 |  |  |  |
Distributions to noncontrolling interests in property partnerships | (13,748,000) | $ (12,763,000) | (53,149,000) | (56,796,000) |  |  |  |
Boston Properties Limited Partnership |  |  |  |  |  |  |  |
Redeemable Noncontrolling Interest, Equity, Preferred, Carrying Amount | 2,335,272,000 |  | 2,335,272,000 |  |  | $ 2,000,591,000 |  |
Beginning Balance |  |  | 5,912,323,000 |  |  |  |  |
Contributions from noncontrolling interests in property partnerships |  |  | 26,968,000 | $ 37,148,000 |  |  |  |
Ending Balance | $ 5,367,322,000 |  | $ 5,367,322,000 |  |  |  |  |
General Partner [Member] |  |  |  |  |  |  |  |
Common Stock, Shares, Outstanding | 1,726,000 | 1,722,000 | 1,726,000 | 1,722,000 | 1,726,000 | 1,722,000 | 1,722,000 | 1,720,000
Contributions, units | 0 | 0 | 3,000 | 1,000 |  |  |  |
Conversion of redeemable partnership units | 0 | 0 | 1,000 | 1,000 |  |  |  |
Limited Partner [Member] |  |  |  |  |  |  |  |
Common Stock, Shares, Outstanding | 152,846,000 | 152,718,000 | 152,846,000 | 152,718,000 | 152,837,000 | 152,736,000 | 152,689,000 | 152,606,000
Contributions, units | 2,000 | 3,000 | 69,000 | 53,000 |  |  |  |
Conversion of redeemable partnership units | 7,000 | 26,000 | 41,000 | 59,000 |  |  |  |
Partners' Capital (General and Limited Partners) [Member] |  |  |  |  |  |  |  |
Beginning Balance | $ 3,562,910,000 | $ 3,820,773,000 | $ 4,054,996,000 | $ 3,664,436,000 |  |  |  |
Cumulative effect of a change in accounting principle | 0 | 0 | (3,864,000) | 4,933,000 |  |  |  |
Contributions, value | (3,915,000) | 354,000 | 1,787,000 | 2,039,000 |  |  |  |
Allocated net income for the period | 109,611,000 | 122,384,000 | 378,081,000 | 433,941,000 |  |  |  |
Distributions | (146,843,000) | (146,718,000) | (440,468,000) | (393,737,000) |  |  |  |
Unearned compensation | (7,205,000) | 768,000 | (7,980,000) | 112,000 |  |  |  |
Conversion of redeemable partnership units | 223,000 | 916,000 | 1,435,000 | 2,112,000 |  |  |  |
Adjustment to reflect redeemable partnership units at redemption value | (9,252,000) | 48,622,000 | (315,953,000) | 133,263,000 |  |  |  |
Acquisition of noncontrolling interest in property partnership | 43,000 |  | (162,462,000) |  |  |  |  |
Ending Balance | 3,505,572,000 | 3,847,099,000 | 3,505,572,000 | 3,847,099,000 |  |  |  |
Preferred Units [Member] |  |  |  |  |  |  |  |
Beginning Balance | 193,623,000 | 193,623,000 | 193,623,000 | 193,623,000 |  |  |  |
Allocated net income for the period | 2,625,000 | 2,625,000 | 7,875,000 | 7,875,000 |  |  |  |
Distributions | (2,625,000) | (2,625,000) | (7,875,000) | (7,875,000) |  |  |  |
Ending Balance | 193,623,000 | 193,623,000 | 193,623,000 | 193,623,000 |  |  |  |
Accumulated Other Comprehensive (Income) Loss [Member] |  |  |  |  |  |  |  |
Beginning Balance | (51,340,000) | (47,695,000) | (47,741,000) | (50,429,000) |  |  |  |
Effective portion of interest rate contracts | (2,022,000) | 1,190,000 | (8,354,000) | 1,190,000 |  |  |  |
Amortization of interest rate contracts | 1,366,000 | 1,368,000 | 4,099,000 | 4,102,000 |  |  |  |
Ending Balance | (51,996,000) | (45,137,000) | (51,996,000) | (45,137,000) |  |  |  |
Noncontrolling interest - property partnerships [Member] |  |  |  |  |  |  |  |
Beginning Balance | 1,696,221,000 | 1,699,181,000 | 1,711,445,000 | 1,683,760,000 |  |  |  |
Cumulative effect of a change in accounting principle | 0 |  | (70,000) |  |  |  |  |
Allocated net income for the period | 18,470,000 | 14,850,000 | 54,782,000 | 46,484,000 |  |  |  |
Effective portion of interest rate contracts |  |  |  | 0 |  |  |  |
Amortization of interest rate contracts | 144,000 | 144,000 | 432,000 | 432,000 |  |  |  |
Acquisition of noncontrolling interest in property partnership |  |  | (24,501,000) |  |  |  |  |
sale of an interest in property partnerships | 4,216,000 |  | 4,216,000 |  |  |  |  |
Contributions from noncontrolling interests in property partnerships | 14,820,000 | 9,616,000 | 26,968,000 | 37,148,000 |  |  |  |
Distributions to noncontrolling interests in property partnerships | (13,748,000) | (12,763,000) | (53,149,000) | (56,796,000) |  |  |  |
Ending Balance | 1,720,123,000 | 1,711,028,000 | 1,720,123,000 | 1,711,028,000 |  |  |  |
Noncontrolling interest - property partnerships [Member] | Boston Properties Limited Partnership |  |  |  |  |  |  |  |
Cumulative effect of a change in accounting principle |  |  | (70,000) |  |  |  |  |
Total Capital [Member] |  |  |  |  |  |  |  |
Beginning Balance | 5,401,414,000 | 5,665,882,000 | 5,912,323,000 | 5,491,390,000 |  |  |  |
Cumulative effect of a change in accounting principle | 0 | 0 | (3,934,000) | 4,933,000 |  |  |  |
Contributions, value | (3,915,000) | 354,000 | 1,787,000 | 2,039,000 |  |  |  |
Allocated net income for the period | 130,706,000 | 139,859,000 | 440,738,000 | 488,300,000 |  |  |  |
Distributions | (149,468,000) | (149,343,000) | (448,343,000) | (401,612,000) |  |  |  |
Unearned compensation | (7,205,000) | 768,000 | (7,980,000) | 112,000 |  |  |  |
Conversion of redeemable partnership units | 223,000 | 916,000 | 1,435,000 | 2,112,000 |  |  |  |
Adjustment to reflect redeemable partnership units at redemption value | (9,252,000) | 48,622,000 | (315,953,000) | 133,263,000 |  |  |  |
Effective portion of interest rate contracts | (2,022,000) | 1,190,000 | (8,354,000) | 1,190,000 |  |  |  |
Amortization of interest rate contracts | 1,510,000 | 1,512,000 | 4,531,000 | 4,534,000 |  |  |  |
Acquisition of noncontrolling interest in property partnership | 43,000 |  | (186,963,000) |  |  |  |  |
sale of an interest in property partnerships | 4,216,000 |  | 4,216,000 |  |  |  |  |
Contributions from noncontrolling interests in property partnerships | 14,820,000 | 9,616,000 | 26,968,000 | 37,148,000 |  |  |  |
Distributions to noncontrolling interests in property partnerships | (13,748,000) | (12,763,000) | (53,149,000) | (56,796,000) |  |  |  |
Ending Balance | 5,367,322,000 | 5,706,613,000 | 5,367,322,000 | 5,706,613,000 |  |  |  |
Noncontrolling interest - Redeemable partnership units [Member] |  |  |  |  |  |  |  |
Redeemable Noncontrolling Interest, Equity, Preferred, Carrying Amount | 2,335,272,000 | 2,190,664,000 | 2,335,272,000 | 2,190,664,000 | $ 2,324,238,000 | $ 2,000,591,000 | $ 2,235,432,000 | $ 2,292,263,000
Cumulative effect of a change in accounting principle | 0 | 0 | (445,000) | 563,000 |  |  |  |
Contributions, value | 0 | (3,000) | 35,482,000 | 34,970,000 |  |  |  |
Allocated net income for the period | 12,506,000 | 13,817,000 | 43,133,000 | 49,128,000 |  |  |  |
Distributions | (17,200,000) | (17,022,000) | (51,591,000) | (45,730,000) |  |  |  |
Unearned compensation | 6,774,000 | 7,689,000 | (5,930,000) | (5,754,000) |  |  |  |
Conversion of redeemable partnership units | (223,000) | (916,000) | (1,435,000) | (2,112,000) |  |  |  |
Adjustment to reflect redeemable partnership units at redemption value | 9,252,000 | (48,622,000) | 315,953,000 | (133,263,000) |  |  |  |
Effective portion of interest rate contracts | (231,000) | 135,000 | (953,000) | 135,000 |  |  |  |
Amortization of interest rate contracts | $ 156,000 | $ 154,000 | $ 467,000 | $ 464,000 |  |  |  |

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