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Derivative and Hedging Instruments (Details) $ in Thousands |  |  | 12 Months Ended
--- | --- | --- | ---
Apr. 24, 2017 USD ($) | Aug. 17, 2016 USD ($) | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) yr swaps | Dec. 31, 2015 USD ($)
Derivative [Line Items] |  |  |  |  |
Mortgage notes payable, net (amounts related to VIEs of $2,939,183 and $2,018,483 at December 31, 2017 and 2016, respectively) |  |  | $ 2,979,281 | $ 2,063,087 |
Other liabilities |  |  | (44,914) | (106,022) | $ (34,005)
Losses from interest rate contracts |  |  | $ 0 | $ (140) | 0
Boston Properties Limited Partnership | Interest Rate Swap [Member] |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Number of interest rate swap agreements entered into | swaps |  |  |  | 17 |
Term of anticipated mortgage loan (in years) | yr |  |  |  | 10 |
Derivative, Average Fixed Interest Rate |  |  |  | 2.423% |
Derivative, Notional Amount |  |  |  | $ 550,000 |
767 Fifth Partners LLC [Member] |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Ownership Percentage by Parent |  |  | 60.00% |  |
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member] |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Number of interest rate swap agreements entered into | swaps |  |  |  | 16 |
Derivative, Average Fixed Interest Rate |  |  |  | 2.619% |
Derivative, Notional Amount |  |  |  | $ 450,000 |
Derivative Asset, Notional Amount |  |  |  | 100,000 |
Derivative Liability, Notional Amount |  |  |  | 350,000 |
Other liabilities | $ 14,400 |  |  |  |
Derivative Instruments, Loss Reclassified from Accumulated OCI into Income, Effective Portion | 14,400 |  |  |  |
Derivative instrument, yearly amount reclassed to interest expense | 1,400 |  |  |  |
Boston Properties Limited Partnership |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Mortgage notes payable, net (amounts related to VIEs of $2,939,183 and $2,018,483 at December 31, 2017 and 2016, respectively) |  |  | $ 2,979,281 | 2,063,087 |
Other liabilities |  |  | (44,914) | (106,022) | (34,005)
Losses from interest rate contracts |  |  | $ 0 | $ (140) | $ 0
Boston Properties Limited Partnership | Interest Rate Swap [Member] |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Other liabilities |  | $ 49,300 |  |  |
Losses from interest rate contracts |  | (100) |  |  |
Derivative Instruments, Loss Reclassified from Accumulated OCI into Income, Effective Portion |  | 49,200 |  |  |
Derivative instrument, yearly amount reclassed to interest expense |  | $ 4,900 |  |  |
Unsecured Senior Note 3.495% | Senior Notes [Member] | Boston Properties Limited Partnership |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Coupon/Stated Rate |  | 2.75% | 2.75% |  |
767 Fifth Avenue (the general motors building) [Member] | Secured Debt [Member] |  |  |  |  |
Derivative [Line Items] |  |  |  |  |
Mortgage notes payable, net (amounts related to VIEs of $2,939,183 and $2,018,483 at December 31, 2017 and 2016, respectively) | $ 2,300,000 |  |  |  |
Coupon/Stated Rate | 3.43% |  |  |  |

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