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(Common Units) (Narrative) (Details) $ / shares in Units, $ in Thousands			3 Months Ended
	Feb. 05, 2021 USD ($) shares	Feb. 02, 2021 USD ($)	Mar. 31, 2021 USD ($) yr $ / shares shares	Dec. 31, 2020 USD ($)
Boston Properties Limited Partnership
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Redeemable Noncontrolling Interest, Equity, Preferred, Carrying Amount \| $			$ 1,780,044	$ 1,643,024
Unvested MYLTIP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
unvested MYLTIP distributions as compared to total distributions (percentage)			10.00%
MYLTIP 2018
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Final awards percentage of target	29.20%
Value of MYLTIP Awards \| $	$ 4,600
Forfeitures, in units	285,925
MYLTIP \| Boston Properties Limited Partnership
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Vesting Period			3 years
MYLTIP 2019 [Member] \| Boston Properties Limited Partnership
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Noncontrolling Interest, Outstanding			219,916
MYLTIP 2020 [Member] \| Boston Properties Limited Partnership
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Noncontrolling Interest, Outstanding			203,278
MYLTIP 2021
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Value of MYLTIP Awards \| $		$ 15,300
Vesting Period		3 years
MYLTIP 2021 \| Boston Properties Limited Partnership
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Noncontrolling Interest, Outstanding			352,021
OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
OP Units for redemption (in shares)			118,290
Restriction on redemption of OP Unit to Common Stock (in years) \| yr			1
Redemption of OP Unit equivalent to Common Stock (in shares)			1
Redeemable Noncontrolling Interest, Equity, Preferred, Carrying Amount \| $			$ 1,800,000
Closing price of common stock (in dollars per share) \| $ / shares			$ 101.26
Vested 2012 OPP units and MYLTIPS
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
OP Units for redemption (in shares)			64,799