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v3.10.0.1

Unsecured Senior Notes Unsecured Senior Notes (Narrative) (Details) - USD ($) $ in Thousands |  |  | 12 Months Ended
--- | --- | --- | ---
Dec. 13, 2018 | Nov. 28, 2018 | Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
Debt Instrument [Line Items] |  |  |  |  |  |
Loss on Extinguishment of Debt |  |  | $ 16,490 |  | $ (496) | $ 371
Repayments of Unsecured Debt |  |  | 699,517 |  | 848,020 | 0
Proceeds from unsecured senior notes |  |  | $ 996,410 |  | 847,935 | 1,989,790
Senior Notes [Member] |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Maximum Leverage Ratio |  |  | 60.00% |  |  |
Maximum Secured Debt Leverage Ratio |  |  | 50.00% |  |  |
Minimum Interest Coverage Ratio |  |  | 1.50 |  |  |
Minimum Unencumbered Asset Value Percentage Of Unsecured Debt |  |  | 150.00% |  |  |
Boston Properties Limited Partnership |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Loss on Extinguishment of Debt |  |  | $ 16,490 |  | (496) | 371
Repayments of Unsecured Debt |  |  | 699,517 |  | 848,020 | 0
Proceeds from unsecured senior notes |  |  | $ 996,410 |  | $ 847,935 | $ 1,989,790
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Notes 4.628% |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Coupon/Stated Rate |  | 4.50% | 4.50% |  |  |
Senior Notes Pricing |  | 99.641% |  |  |  |
Effective Rate |  | 4.628% | 4.628% | [1] |  |
Proceeds from unsecured senior notes |  | $ 988,100 |  |  |  |
Debt Instrument, Face Amount |  | $ 1,000,000 |  |  |  |
Boston Properties Limited Partnership | Senior Notes [Member] | Unsecured Senior Notes 5.967% |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Debt Instrument, Increase, Accrued Interest | $ 6,600 |  |  |  |  |
Debt Instrument, Redemption Price, Percentage | 102.28% |  |  |  |  |
Loss on Extinguishment of Debt | $ 16,500 |  |  |  |  |
Redemption Premium | $ 16,000 |  |  |  |  |
Coupon/Stated Rate | 5.875% |  |  |  |  |
Repayments of Unsecured Debt | $ 722,600 |  |  |  |  |
Debt Instrument, Face Amount | $ 700,000 |  |  |  |  |
[1] | Yield on issuance date including the effects of discounts on the notes, settlements of interest rate contracts and the amortization of financing costs.

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