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

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Present value of lessee's discounted obligation for lease payments from operating lease.

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Leases Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
Leases Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018	Jan. 01, 2019	Dec. 31, 2018
Cumulative effect of a change in accounting principle	$ 4,379	$ (5,496)
Right of use assets - operating leases	151,166		$ 151,800	$ 0
Lease liabilities - operating leases	199,653		$ 199,300	0
Boston Properties Limited Partnership
Right of use assets - operating leases	151,166			0
Lease liabilities - operating leases	199,653			$ 0
Dividends In Excess Of Earnings [Member]
Cumulative effect of a change in accounting principle	3,864	(4,933)
Dividends In Excess Of Earnings [Member] \| Boston Properties Limited Partnership
Cumulative effect of a change in accounting principle	3,900
Noncontrolling Interests - Common units [Member]
Cumulative effect of a change in accounting principle	445	$ (563)
Noncontrolling Interests - Common units [Member] \| Boston Properties Limited Partnership
Cumulative effect of a change in accounting principle	400
Noncontrolling interest - property partnerships [Member]
Cumulative effect of a change in accounting principle	70
Noncontrolling interest - property partnerships [Member] \| Boston Properties Limited Partnership
Cumulative effect of a change in accounting principle	$ (70)