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Leases Narrative (Details)	3 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2018 USD ($)	Jan. 01, 2019 USD ($)
Finance leases under development	3	3
Cumulative effect of a change in accounting principle		$ 4,379,000	$ (5,496,000)
Right of use assets - operating leases	$ 149,231,000	149,231,000		$ 151,800,000
Lease liabilities - operating leases	$ 199,755,000	199,755,000		$ 199,300,000
Lessee, Finance Lease, Description	four
Boston Properties Limited Partnership
Right of use assets - operating leases	$ 149,231,000	149,231,000
Lease liabilities - operating leases	199,755,000	199,755,000
Dividends In Excess Of Earnings [Member]
Cumulative effect of a change in accounting principle		3,864,000	(4,933,000)
Dividends In Excess Of Earnings [Member] | Boston Properties Limited Partnership
Cumulative effect of a change in accounting principle		3,900,000
Noncontrolling Interests - Common units [Member]
Cumulative effect of a change in accounting principle		445,000	$ (563,000)
Noncontrolling Interests - Common units [Member] | Boston Properties Limited Partnership
Cumulative effect of a change in accounting principle		400,000
Noncontrolling interest - property partnerships [Member]
Cumulative effect of a change in accounting principle	$ 0	70,000
Noncontrolling interest - property partnerships [Member] | Boston Properties Limited Partnership
Cumulative effect of a change in accounting principle		$ 70,000

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Amount of the cumulative effect on retained earnings net of related income tax effect.

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