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Leases Narrative (Details)	3 Months Ended	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jan. 01, 2019 USD ($)	Dec. 31, 2018 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	$ 149,839,000	149,839,000		$ 151,800,000	$ 0
Lease liabilities - operating leases	$ 199,344,000	199,344,000		$ 199,300,000	0
Lessee, Finance Lease, Description	four
Boston Properties Limited Partnership
Right of use assets - operating leases	$ 149,839,000	149,839,000			0
Lease liabilities - operating leases	199,344,000	199,344,000			$ 0
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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-Topic 250
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Description of lessee's finance lease.

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-Topic 842
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-Section 50
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