Consolidated Statements of Changes in Equity (USD $) In Thousands, unless otherwise specified	Total	Real Estate Funds [Member]	All Other Except Real Estate Fund [Member]	Preferred Units [Member]	Class A Units Owned By Vornado [Member]	Earnings Less Than Distributions	Accumulated Other Comprehensive Income (Loss)	Non-controlling Interests in Consolidated Subsidiaries	Non-controlling Interests in Consolidated Subsidiaries Real Estate Funds [Member]	Non-controlling Interests in Consolidated Subsidiaries All Other Except Real Estate Fund [Member]
Beginning balance, Value at Dec. 31, 2011	$ 7,508,447			$ 1,021,660	$ 7,134,631	$ (1,401,704)	$ 73,729	$ 680,131
Beginning balance, Units at Dec. 31, 2011				42,187	185,080
Net income	602,648					571,720		30,928
Net income attributable to redeemable partnership units	(40,595)					(40,595)
Distributions to Vornado	(384,353)					(384,353)
Distributions to preferred unitholders	(56,187)					(56,187)
Issuance of preferred units, Units				12,000
Issuance of preferred units, Value	291,144			291,144
Redemption of preferred units, Units				(3,000)
Redemption of preferred units, value	(75,000)			(75,000)
Class A units issued to Vornado:
Upon redemption of redeemable Class A units, at redemption value, Units					624
Upon redemption of redeemable Class A units, at redemption value, Value	51,216				51,216
Under Vornado's Omnibus Share plan, Units					414
Under Vornado's Omnibus Share plan, Value	(7,458)				8,931	(16,389)
Under Vornado's dividend reinvestment plan, Units					15
Under Vornado's dividend reinvestment plan, Value	1,270				1,270
Contributions:
Contributions		120,606	140						120,606	140
Distributions:
Distributions		(44,910)	(10)						(44,910)	(10)
Conversion of Series A preferred units to Class A units, Units				(2)	3
Conversion of Series A preferred units to Class A units, Value				(105)	105
Deferred compensation units and options, Units					7
Deferred compensation units and options, Value	10,670				11,009	(339)
Change in unrealized net (loss) gain on available-for-sale securities	(202,167)						(202,167)
Amounts reclassified related to sale of available-for-sale securities	0
Pro rata share of other comprehensive loss of nonconsolidated subsidiaries	(38,861)						(38,861)
Change in value of interest rate swap	(8,868)						(8,868)
Adjustment to carry Class A redeemable units at redemption value	(63,657)				(63,657)
Redeemable partnership units' share of above adjustments	15,717						15,717
Preferred unit redemptions	11,700					11,700
Other	(2,638)					(2,971)	343	(10)
Ending balance, Value at Sep. 30, 2012	7,688,854			1,237,699	7,143,505	(1,319,118)	(160,107)	786,875
Ending balance, Units at Sep. 30, 2012				51,185	186,143
Beginning balance, Value at Dec. 31, 2012	7,904,144			1,240,278	7,202,878	(1,573,275)	(18,946)	1,053,209
Beginning balance, Units at Dec. 31, 2012				51,185	186,735
Net income	603,499					553,450		50,049
Net income attributable to redeemable partnership units	(28,960)					(28,960)
Distributions to Vornado	(409,332)					(409,332)
Distributions to preferred unitholders	(62,439)					(62,439)
Issuance of preferred units, Units				12,000
Issuance of preferred units, Value	290,536			290,536
Redemption of preferred units, Units				(10,500)
Redemption of preferred units, value	(253,269)			(253,269)
Class A units issued to Vornado:
Upon redemption of redeemable Class A units, at redemption value, Units					234
Upon redemption of redeemable Class A units, at redemption value, Value	19,627				19,627
Under Vornado's Omnibus Share plan, Units					66
Under Vornado's Omnibus Share plan, Value	3,681				3,681
Under Vornado's dividend reinvestment plan, Units					16
Under Vornado's dividend reinvestment plan, Value	1,376				1,376
Contributions:
Contributions		24,328	15,687						24,328	15,687
Distributions:
Distributions		(47,268)	(126,799)						(47,268)	(126,799)
Conversion of Series A preferred units to Class A units, Units				(2)	3
Conversion of Series A preferred units to Class A units, Value				(90)	90
Deferred compensation units and options, Units					(6)
Deferred compensation units and options, Value	6,877				7,182	(305)
Change in unrealized net (loss) gain on available-for-sale securities	160,886						160,886
Amounts reclassified related to sale of available-for-sale securities	(42,404)						(42,404)
Pro rata share of other comprehensive loss of nonconsolidated subsidiaries	(25,023)						(25,023)
Change in value of interest rate swap	14,265						14,265
Adjustment to carry Class A redeemable units at redemption value	(43,709)				(43,709)
Redeemable partnership units' share of above adjustments	(5,982)						(5,982)
Preferred unit redemptions	(1,130)					(1,130)
Deconsolidation of partially owned entity	(165,427)							(165,427)
Other	(5,330)				(25)	(5,672)	531	(164)
Ending balance, Value at Sep. 30, 2013	$ 7,827,834			$ 1,277,455	$ 7,191,100	$ (1,527,663)	$ 83,327	$ 803,615
Ending balance, Units at Sep. 30, 2013				52,683	187,048