Derivative Instruments Loss Reclassified From Accumulated OCI Into Income Effective (yearly amount)

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- Definition

Maximum period of hedging exposure to the variability in future cash flows for forecasted transactions (in years)

+ References

No definition available.

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- Definition

Number of interest rate swap agreements entered into

+ References

No definition available.

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- Definition

Term of anticipated mortgage loan (in years)

+ References

No definition available.

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- 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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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

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.

+ References

No definition available.

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- Definition

Average fixed interest rate related to the group of interest rate derivatives.

+ References

No definition available.

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- Definition

The effective portion of loss reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

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- Definition

Aggregate net gain (loss) on all derivative instruments recognized in earnings during the period, before tax effects.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5618551-113959

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- Definition

Amount of increase (decrease) in operating liabilities classified as other.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3602-108585

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- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

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- Definition

Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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Derivative Instruments and Hedging Activities (Details) $ in Thousands			3 Months Ended		9 Months Ended		12 Months Ended
	Apr. 24, 2017 USD ($)	Aug. 17, 2016 USD ($) yr	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($) swaps yr	Dec. 31, 2015 USD ($) swaps	Dec. 31, 2016 USD ($)
Debt Instrument [Line Items]
Mortgage notes payable, net			$ 2,982,067		$ 2,982,067			$ 2,063,087
Cash payment to settle interest rate swap contracts					(65,031)	$ (114,321)
Losses from interest rate contracts			$ 0	$ 140	$ 0	$ 140
Boston Properties Limited Partnership \| Interest Rate Swap [Member]
Debt Instrument [Line Items]
Number of interest rate swap agreements entered into (swap contracts) \| swaps							17
Term of anticipated mortgage loan (in years) \| yr		10
Average Fixed Interest Rate							2.423%
Notional Amount							$ 550,000
Cash payment to settle interest rate swap contracts		$ 49,300
Losses from interest rate contracts		100
Derivative Instruments, Loss Reclassified from Accumulated OCI into Income, Effective Portion		49,200
Derivative Instruments Loss Reclassified From Accumulated OCI Into Income Effective yearly amount		$ 4,900
767 Fifth Partners LLC [Member]
Debt Instrument [Line Items]
Ownership Percentage by the Company			60.00%		60.00%
767 Fifth Partners LLC [Member] \| Interest Rate Swap [Member]
Debt Instrument [Line Items]
Number of interest rate swap agreements entered into (swap contracts) \| swaps						16
Maximum period of hedging exposure to the variability in future cash flows for forecasted transactions (in years) \| yr						10
Average Fixed Interest Rate				2.619%		2.619%
Notional Amount				$ 450,000		$ 450,000		450,000
Cash payment to settle interest rate swap contracts	$ 14,400
Derivative Instruments, Loss Reclassified from Accumulated OCI into Income, Effective Portion	14,400
Derivative Instruments Loss Reclassified From Accumulated OCI Into Income Effective yearly amount	1,400
Unsecured Debt [Member] \| Boston Properties Limited Partnership
Debt Instrument [Line Items]
Coupon/Stated Rate		2.75%
Boston Properties Limited Partnership
Debt Instrument [Line Items]
Mortgage notes payable, net			$ 2,982,067		$ 2,982,067			$ 2,063,087
Cash payment to settle interest rate swap contracts					(65,031)	(114,321)
Losses from interest rate contracts			$ 0	$ 140	$ 0	$ 140
767 Fifth Avenue (the General Motors Building) \| Secured Debt [Member]
Debt Instrument [Line Items]
Mortgage notes payable, net	$ 2,300,000
Coupon/Stated Rate	3.43%