(Common Units) (Narrative) (Details) $ / shares in Units, $ in Thousands		3 Months Ended
	Feb. 06, 2020 USD ($) shares	Mar. 31, 2020 USD ($) shares yr $ / shares	Dec. 31, 2019 USD ($)
MYLTIP 2017 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Final awards percentage of target	83.80%
Value of MYLTIP Awards | $	$ 17,600
MYLTIP Units forfeited	270,942
OP Units [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
OP Units for redemption (in shares)		461,856
Redemption of OP units issued on conversion of LTIP, OPP and MYLTIP units (in shares)		71,303
MYLTIP Units distribution as percentage of OP Unit distribution prior to measurement date		10.00%
Restriction on redemption of OP Unit to Common Stock (in years) | yr		1
Redemption of OP Unit equivalent to Common Stock (in shares)		1
Common units of operating partnership if converted value | $		$ 1,600,000
Closing price of common stock (in dollars per share) | $ / shares		$ 92.23
Boston Properties Limited Partnership
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Common units of operating partnership if converted value | $		$ 1,639,855	$ 2,468,753
Boston Properties Limited Partnership | MYLTIP 2017 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2017 MYLTIP		116,167
Boston Properties Limited Partnership | MYLTIP 2018
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2018 MYLTIP		336,195
Boston Properties Limited Partnership | MYLTIP 2019 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2019 MYLTIPS		220,734
Boston Properties Limited Partnership | MYLTIP 2020 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
2020 MYLTIP		203,278