Noncontrolling Interests Common units for Boston Properties Limited Partnership (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Noncontrolling Interest [Line Items]
Conversion of redeemable partnership units		$ 0
Cumulative effect of a change in accounting principle	$ 5,496	(2,035)
Other comprehensive income (loss)	(47,695)		$ (50,429)
Noncontrolling Interests [Member]
Noncontrolling Interest [Line Items]
Conversion of redeemable partnership units	11,328	10,840
Cumulative effect of a change in accounting principle	563	(1,763)
Boston Properties Limited Partnership
Noncontrolling Interest [Line Items]
Cumulative effect of a change in accounting principle	4,933	(272)
Boston Properties Limited Partnership \| Noncontrolling Interests [Member]
Noncontrolling Interest [Line Items]
Beginning balance	2,292,263	2,262,040
Contributions	34,973	31,532
Net income	35,311	26,933
Distributions	(28,708)	(26,977)
Conversion of redeemable partnership units	(1,196)	(16,422)
Unearned compensation	(13,443)	(12,344)
Cumulative effect of a change in accounting principle	563	(1,763)
Other comprehensive income (loss)	310	(104)
Adjustments to reflect redeemable preferred units at redemption value	(84,641)	(92,740)
Ending balance	$ 2,235,432	$ 2,170,155

Adjustments To Reflect Redeemable Preferred Units At Redemption Value.

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Contributions To Noncontrolling Interest Common Units.

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Distributions to noncontrolling interest common units

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Net Income Attributable to Common Units

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Noncontrolling Interest, Unearned Compensation.

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Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of increase in noncontrolling interest from subsidiary issuance of equity interests to noncontrolling interest holders.

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