Debt Instrument, Number of Extension Options

No definition available.

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- Definition

Debt Instrument, Period of Extension Option

+ References

No definition available.

+ Details

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- Definition

Disposal Group Including Discontinued Operation, Ownership Percentage in Disposed Asset

+ References

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- Definition

Line of Credit Facility, Basis Point Fee

+ References

No definition available.

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- Definition

Line of Credit Facility, Threshold Amount for Basis Point Fee

+ References

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- Definition

Secured Debt, Amount Transferred to Liabilities Related to Net Assets Held for Sale

+ References

No definition available.

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- Definition

Represents the carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations and other loans payable.

+ References

No definition available.

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- Definition

The portion of the carrying amount of long-term secured loans outstanding as of the balance sheet date, including current maturities, which accrues interest at a set, unchanging rate.

+ References

No definition available.

+ Details

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- Definition

The portion of the carrying amount of long-term secured loans outstanding as of the balance sheet date, including current maturities, which accrues interest at a rate subject to change from time to time.

+ References

No definition available.

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- Definition

Secured Debt, Deferred Finance Costs, Net

+ References

No definition available.

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- Definition

Secured Debt, Gross

+ References

No definition available.

+ Details

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- Definition

The aggregate fair value of assets that are already posted, at the end of the reporting period, as collateral for derivative instruments with credit-risk-related contingent features.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4H
-Subparagraph (d)
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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

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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

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
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-Subparagraph (SX 210.5-02.17)
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- Definition

Amount of Federal Home Loan Bank (FHLBank) advances to member financial institutions.

+ References

No definition available.

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- Definition

Interest rate of advances made and reported by Federal Home Loan Bank (FHLBank).

+ References

No definition available.

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-SubTopic 10
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- Definition

The interest rate applicable to the portion of the carrying amount of long-term borrowings outstanding as of the balance sheet date, including current maturities, which accrues interest at a set, unchanging rate.

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-Subparagraph (SX 210.5-02.22(a)(1))
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- Definition

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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

The percentage rate used to calculate dividend payments on preferred stock.

+ References

No definition available.

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- Definition

As of the reporting date, the aggregate carrying amount of all noncontrolling interests which are redeemable by the (parent) entity (1) at a fixed or determinable price on a fixed or determinable date, (2) at the option of the holder of the noncontrolling interest, or (3) upon occurrence of an event that is not solely within the control of the (parent) entity. This item includes noncontrolling interest holder's ownership (or holders' ownership) regardless of the type of equity interest (common, preferred, other) including all potential organizational (legal) forms of the investee entity.

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-Name Accounting Standards Codification
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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
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-Subparagraph (SX 210.9-03(16))
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- Definition

The per share liquidation preference (or restrictions) of stock classified as temporary equity that has a preference in involuntary liquidation considerably in excess of the par or stated value of the shares. The liquidation preference is the difference between the preference in liquidation and the par or stated values of the share. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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Mortgages and Other Loans Payable (Details)		1 Months Ended		3 Months Ended	12 Months Ended
Mortgages and Other Loans Payable (Details)	Dec. 06, 2015 USD ($)	Oct. 31, 2016	Aug. 31, 2016	Dec. 31, 2016 USD ($) extenstion_option $ / shares	Dec. 31, 2016 USD ($) $ / shares	Jan. 31, 2017 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)
Debt Instrument [Line Items]
Total fixed rate debt				$ 3,518,127,000	$ 3,518,127,000			$ 5,816,010,000
Total floating rate debt				622,585,000	622,585,000			1,205,494,000
Total fixed rate and floating rate debt				4,140,712,000	4,140,712,000			7,021,504,000
Mortgages reclassed to liabilities related to assets held for sale (15)				0	0			(29,000,000)
Total mortgages and other loans payable				4,140,712,000	4,140,712,000			6,992,504,000
Deferred financing costs, net of amortization				(66,882,000)	(66,882,000)			(110,584,000)
Total mortgages and other loans payable				4,073,830,000	4,073,830,000			6,881,920,000
Debt Issuance Costs, Net				82,300,000	82,300,000			130,300,000
Federal Home Loan Bank Advances outstanding				$ 205,000,000	$ 205,000,000
Federal Home Loan Bank, advances, weighted-average borrowing rate (as a percent)				0.92%	0.92%
Book value of collateral				$ 6,000,000,000	$ 6,000,000,000			10,800,000,000
Series J Preferred Units
Debt Instrument [Line Items]
Total fixed rate debt				4,000,000	4,000,000			4,000,000
Temporary Equity, Carrying Amount, Attributable to Noncontrolling Interest				$ 4,000,000	$ 4,000,000
Preferred Units (as a percent)					3.75%
Preferred Units, liquidation preference (in dollars per unit) \| $ / shares				$ 1,000.00	$ 1,000.00
Series J Preferred Units \| Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				3.75%	3.75%
FHLB Advance Maturing in January 2017 [Member]
Debt Instrument [Line Items]
Total fixed rate debt				$ 105,000,000	$ 105,000,000			0
FHLB Advance Maturing in January 2017 [Member] \| Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				1.03%	1.03%
FHLB Advance Maturing in January 2017, 2 [Member]
Debt Instrument [Line Items]
Total fixed rate debt				$ 100,000,000	$ 100,000,000			0
FHLB Advance Maturing in January 2017, 2 [Member] \| Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				0.80%	0.80%
Unsecured Debt [Member]
Debt Instrument [Line Items]
Total fixed rate debt				$ 16,000,000	$ 16,000,000			16,000,000
Unsecured Debt [Member] \| Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				4.81%	4.81%
Master Repurchase Agreement
Debt Instrument [Line Items]
Total floating rate debt				$ 184,642,000	$ 184,642,000			253,424,000
Maximum facility capacity				$ 300,000,000.0	$ 300,000,000.0
Basis Point Fee (as a percent)	0.25%
Threshold amount for basis point fee to be applicable (less than)	$ 150,000,000.0
Master Repurchase Agreement \| Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)				3.04%	3.04%
Master Repurchase Agreement \| Minimum \| LIBOR
Debt Instrument [Line Items]
Credit facility, interest rate (as a percent)					2.25%
Master Repurchase Agreement \| Maximum \| LIBOR
Debt Instrument [Line Items]
Credit facility, interest rate (as a percent)					4.00%
FHLB Advance Maturing in December 2016
Debt Instrument [Line Items]
Total floating rate debt				$ 0	$ 0			45,750,000
485 Lexington Avenue (3)
Debt Instrument [Line Items]
Total fixed rate debt				$ 450,000,000	$ 450,000,000			450,000,000
485 Lexington Avenue (3) \| Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				5.61%	5.61%
762 Madison Avenue
Debt Instrument [Line Items]
Total fixed rate debt				$ 7,694,000	$ 7,694,000			7,872,000
762 Madison Avenue \| Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				3.86%	3.86%
One Madison Avenue
Debt Instrument [Line Items]
Total fixed rate debt				$ 517,806,000	$ 517,806,000			542,817,000
One Madison Avenue \| Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				5.91%	5.91%
100 Church Street
Debt Instrument [Line Items]
Total fixed rate debt				$ 221,446,000	$ 221,446,000			225,099,000
100 Church Street \| Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				4.68%	4.68%
919 Third Avenue
Debt Instrument [Line Items]
Total fixed rate debt				$ 500,000,000	$ 500,000,000			500,000,000
Interest in property (as a percent)				51.00%	51.00%
919 Third Avenue \| Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				5.12%	5.12%
420 Lexington Avenue
Debt Instrument [Line Items]
Total fixed rate debt				$ 300,000,000	$ 300,000,000			300,000,000
420 Lexington Avenue \| Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				3.99%	3.99%
1515 Broadway
Debt Instrument [Line Items]
Total fixed rate debt				$ 888,531,000	$ 888,531,000			900,000,000
1515 Broadway \| Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				3.93%	3.93%
400 East 58th Street
Debt Instrument [Line Items]
Total fixed rate debt				$ 40,000,000	$ 40,000,000			28,990,000
400 East 58th Street \| Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				3.00%	3.00%
Term (in Years)					5 years
Landmark Square
Debt Instrument [Line Items]
Total fixed rate debt				$ 100,000,000	$ 100,000,000			79,562,000
Landmark Square \| Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				5.05%	5.05%
885 Third Avenue
Debt Instrument [Line Items]
Total fixed rate debt				$ 267,650,000	$ 267,650,000			267,650,000
885 Third Avenue \| Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)				6.26%	6.26%
400 East 57th Street
Debt Instrument [Line Items]
Total fixed rate debt				$ 0	$ 0			67,644,000
Ownership percentage in disposed asset		49.00%
11 Madison Avenue
Debt Instrument [Line Items]
Total fixed rate debt				0	0			1,400,000,000
388-390 Greenwich Street
Debt Instrument [Line Items]
Total fixed rate debt				0	0			1,004,000,000
Total floating rate debt				0	0			446,000,000
500 West Putnam Avenue
Debt Instrument [Line Items]
Total fixed rate debt				0	0			22,376,000
719 Seventh Avenue
Debt Instrument [Line Items]
Total floating rate debt				$ 37,388,000	$ 37,388,000			0
719 Seventh Avenue \| Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)				3.55%	3.55%
183, 187 Broadway & 5-7 Dey Street
Debt Instrument [Line Items]
Total floating rate debt				$ 58,000,000	$ 58,000,000			40,000,000
183, 187 Broadway & 5-7 Dey Street \| Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)				3.16%	3.16%
1080 Amsterdam (13)
Debt Instrument [Line Items]
Total floating rate debt				$ 3,525,000	$ 3,525,000			3,525,000
1080 Amsterdam (13) \| Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)				4.23%	4.23%
220 East 42nd Street
Debt Instrument [Line Items]
Total floating rate debt				$ 275,000,000	$ 275,000,000			275,000,000
220 East 42nd Street \| Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)				2.08%	2.08%
One Vanderbilt
Debt Instrument [Line Items]
Total floating rate debt				$ 64,030,000	$ 64,030,000			0
One Vanderbilt \| Weighted Average
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)				4.09%	4.09%
One Vanderbilt \| Construction Loans [Member]
Debt Instrument [Line Items]
Term (in Years)					5 years
Maximum facility capacity							$ 1,500,000,000.0
Debt Instrument, Number of Extension Options \| extenstion_option				2
Debt Instrument, Period of Extension Option					1 year
One Vanderbilt \| Construction Loans [Member] \| LIBOR
Debt Instrument [Line Items]
Credit facility, interest rate (as a percent)					3.50%
600 Lexington Avenue
Debt Instrument [Line Items]
Total floating rate debt				$ 0	$ 0			112,795,000
248-252 Bedford Avenue
Debt Instrument [Line Items]
Total floating rate debt				$ 0	$ 0			29,000,000
Debt Issuance Costs, Net								$ 600,000
11 Madison Avenue
Debt Instrument [Line Items]
Ownership percentage in disposed asset			40.00%
Subsequent Event \| 485 Lexington Avenue (3)
Debt Instrument [Line Items]
Total fixed rate debt						$ 450,000,000
Subsequent Event \| 485 Lexington Avenue (3) \| Weighted Average
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)						4.22%
Subsequent Event \| 1080 Amsterdam (13)
Debt Instrument [Line Items]
Total floating rate debt						$ 47,000,000