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Derivative Instruments and Hedging Activities Derivative Instrument and Hedging Activities Notional Table (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Aug. 17, 2016	Jan. 06, 2016
Derivative [Line Items]
Fair Value	$ 5,712	$ (30,156)	$ (85,285)	$ (18,050)
Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount					$ 950,000
Fair Value					(10,302)
Boston Properties Limited Partnership | Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount					550,000	$ 550,000
Fair Value					(4,231)
Boston Properties Limited Partnership | Interest Rate Swap [Member] | Interest Rate Swap Range 2.348% - 2.571% [Member]
Derivative [Line Items]
Derivative Liability, Notional Amount					$ 400,000
Derivative, Lower Fixed Interest Rate Range					2.348%
Derivative, Higher Fixed Interest Rate Range					2.571%
Fair Value					$ (5,419)
Boston Properties Limited Partnership | Interest Rate Swap [Member] | Interest Rate Swap Range 2.129% - 2.325% [Member]
Derivative [Line Items]
Derivative Asset, Notional Amount					$ 150,000
Derivative, Lower Fixed Interest Rate Range					2.129%
Derivative, Higher Fixed Interest Rate Range					2.325%
Fair Value					$ 1,188
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount	450,000		450,000		400,000		$ 50,000
Fair Value					(6,071)
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member] | Interest Rate Swap Range 2.336% - 2.950% [Member]
Derivative [Line Items]
Derivative Liability, Notional Amount	$ 450,000		$ 450,000
Derivative, Lower Fixed Interest Rate Range	2.336%		2.336%
Derivative, Higher Fixed Interest Rate Range	2.95%		2.95%
Fair Value			$ (46,405)
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member] | Interest Rate Swap Range 2.677% - 2.950% [Member]
Derivative [Line Items]
Derivative Liability, Notional Amount					$ 250,000
Derivative, Lower Fixed Interest Rate Range					2.677%
Derivative, Higher Fixed Interest Rate Range					2.95%
Fair Value					$ (7,247)
767 Fifth Partners LLC [Member] | Interest Rate Swap [Member] | Interest Rate Swap Range 2.336% - 2.430% [Member]
Derivative [Line Items]
Derivative Asset, Notional Amount					$ 150,000
Derivative, Lower Fixed Interest Rate Range					2.336%
Derivative, Higher Fixed Interest Rate Range					2.43%
Fair Value					$ 1,176

X

- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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Nominal or face amount used to calculate payments on the derivative asset.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
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High end of the range of fixed interest rates when a range is presented for a group of interest rate derivatives.

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Nominal or face amount used to calculate payments on the derivative liability.

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