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Unsecured Senior Notes Narrative (Details) - USD ($) $ in Thousands			6 Months Ended
		Jun. 21, 2019	Jun. 30, 2019	Jun. 30, 2018
Debt Instrument [Line Items]
Proceeds from unsecured senior notes			$ 848,428	$ 0
Boston Properties Limited Partnership
Debt Instrument [Line Items]
Proceeds from unsecured senior notes			848,428	$ 0
Boston Properties Limited Partnership | Senior Notes [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 8,450,000
Debt Instrument, Covenant Description			The indenture relating to the unsecured senior notes contains certain financial restrictions and requirements, including (1) a leverage ratio not to exceed 60%, (2) a secured debt leverage ratio not to exceed 50%, (3) an interest coverage ratio of greater than 1.50 and (4) an unencumbered asset value of not less than 150% of unsecured debt.
Boston Properties Limited Partnership | Senior Notes [Member] | 10 Year Unsecured Senior Notes 3.505% [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 850,000	$ 850,000
Senior Notes Pricing		99.815%
Debt Instrument, Interest Rate, Stated Percentage		3.40%	3.40%
Debt Instrument, Interest Rate, Effective Percentage	[1]	3.505%	3.505%
Proceeds from unsecured senior notes		$ 841,300
[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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