Consolidated Statements of Changes in Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	JBGS	Real estate fund investments	Other	Preferred Units	Common Shares	Additional Capital	Earnings Less Than Distributions	Earnings Less Than Distributions JBGS	Accumulated Other Comprehensive Income	Non- controlling Interests in Consolidated Subsidiaries	Non- controlling Interests in Consolidated Subsidiaries Real estate fund investments	Non- controlling Interests in Consolidated Subsidiaries Other	Vornado Realty L.P.	Vornado Realty L.P. JBGS	Vornado Realty L.P. Real estate fund investments	Vornado Realty L.P. Other	Vornado Realty L.P. Preferred Units	Vornado Realty L.P. Class A Units Owned by Vornado	Vornado Realty L.P. Earnings Less Than Distributions	Vornado Realty L.P. Earnings Less Than Distributions JBGS	Vornado Realty L.P. Accumulated Other Comprehensive Income	Vornado Realty L.P. Non- controlling Interests in Consolidated Subsidiaries	Vornado Realty L.P. Non- controlling Interests in Consolidated Subsidiaries Real estate fund investments	Vornado Realty L.P. Non- controlling Interests in Consolidated Subsidiaries Other	Series G & I Preferred Stock	Series G & I Preferred Stock Vornado Realty L.P.	Series G & I Preferred Stock Vornado Realty L.P. Earnings Less Than Distributions
Beginning balance, shares at Dec. 31, 2016					42,825	189,101												42,825	189,101
Beginning balance, value at Dec. 31, 2016	$ 7,618,496				$ 1,038,055	$ 7,542	$ 7,153,332	$ (1,419,382)		$ 118,972	$ 719,977			$ 7,618,496				$ 1,038,055	$ 7,160,874	$ (1,419,382)		$ 118,972	$ 719,977
Net income (loss) attributable to Vornado / Vornado Realty L.P.	183,084							183,084						192,141						192,141
Net income attributable to redeemable partnership units	(9,057)													(9,057)						(9,057)
Net income attributable to noncontrolling interests in consolidated subsidiaries	18,436		$ 9,684								18,436			18,436									18,436
Dividends on common shares	(382,552)							(382,552)
Distributions to Vornado														(382,552)						(382,552)
Dividends on preferred shares / Distributions to preferred unitholders	(48,386)							(48,386)						(48,386)						(48,386)
Common shares issued: / Class A Units issued to Vornado
Upon redemption of Class A units, at redemption value, shares						349													349
Upon redemption of Class A units, at redemption value, value	34,564					$ 14	34,550							34,564					$ 34,564
Under Vornado's employees' share option plan, shares						409													409
Under Vornado's employees' share option plan, value	23,892					$ 15	23,877							23,892					$ 23,892
Under Vornado's dividend reinvestment plan, shares						12													12
Under Vornado's dividend reinvestment plan, value	1,119					$ 0	1,119							1,119					$ 1,119
Contributions:
Contributions	1,044										1,044			1,044									1,044
Distributions:
Distributions	(25,663)	$ (2,430,427)	(20,851)	$ (1,815)					$ (2,430,427)			$ (20,851)	$ (1,815)		$ (2,430,427)	$ (20,851)	$ (1,815)				$ (2,430,427)			$ (20,851)	$ (1,815)
Conversion of Series A preferred shares to common shares / Conversion of Series A preferred units to Class A units, shares					(2)	2												(2)	2
Conversion of Series A preferred shares to common shares / Conversion of Series A preferred units to Class A units, value	0				$ (44)	$ 0	44							0				$ (44)	$ 44
Deferred compensation shares and options, shares						1													1
Deferred compensation shares and options, value	1,557					$ 0	1,975	(418)						1,557					$ 1,975	(418)
Reduction in unrealized net gain on available-for-sale securities	(10,559)									(10,559)				(10,559)								(10,559)
Pro rata share of amounts reclassified related to a nonconsolidated subsidiary	8,622									8,622				8,622								8,622
Pro rata share of other comprehensive income (loss) of nonconsolidated subsidiaries	(1,657)									(1,657)				(1,657)								(1,657)
Increase in value of interest rate swaps	6,611									6,611				6,611								6,611
Adjustments to carry redeemable Class A units at redemption value	286,928						286,928							286,928					$ 286,928
Redeemable noncontrolling interests' share of above adjustments	(188)									(188)				(188)								(188)
Other, shares																			4
Other, value	(345)					$ 4	(2)	(46)		0	(297)			(345)					$ (2)	(46)		0	(297)
Ending balance, shares at Sep. 30, 2017					42,823	189,878												42,823	189,878
Ending balance, value at Sep. 30, 2017	5,287,573				$ 1,038,011	$ 7,571	7,501,823	(4,098,127)		121,801	716,494			5,287,573				$ 1,038,011	$ 7,509,394	(4,098,127)		121,801	716,494
Beginning balance, value at Jun. 30, 2017										115,839
Net income (loss) attributable to Vornado / Vornado Realty L.P.	(12,898)													(14,776)
Net income attributable to redeemable partnership units	1,878
Net income attributable to noncontrolling interests in consolidated subsidiaries	4,022		1,486											4,022
Distributions:
Reduction in unrealized net gain on available-for-sale securities	5,656													5,656
Pro rata share of amounts reclassified related to a nonconsolidated subsidiary	(646)													(646)
Pro rata share of other comprehensive income (loss) of nonconsolidated subsidiaries	(626)													(626)
Ending balance, shares at Sep. 30, 2017					42,823	189,878												42,823	189,878
Ending balance, value at Sep. 30, 2017	5,287,573				$ 1,038,011	$ 7,571	7,501,823	(4,098,127)		121,801	716,494			5,287,573				$ 1,038,011	$ 7,509,394	(4,098,127)		121,801	716,494
Cumulative effect of accounting change (see Note 3)	14,519							122,893		(108,374)				14,519						122,893		(108,374)
Beginning balance, shares at Dec. 31, 2017					36,800	189,984												36,800	189,984
Beginning balance, value at Dec. 31, 2017	5,007,701				$ 891,988	$ 7,577	7,492,658	(4,183,253)		128,682	670,049			5,007,701				$ 891,988	$ 7,500,235	(4,183,253)		128,682	670,049
Net income (loss) attributable to Vornado / Vornado Realty L.P.	336,927							336,927						355,919						355,919
Net income attributable to redeemable partnership units	(18,992)													(18,992)						(18,992)
Net income attributable to noncontrolling interests in consolidated subsidiaries	(31,137)		(34,338)								(31,137)			(31,137)									(31,137)
Dividends on common shares	(359,456)							(359,456)
Distributions to Vornado														(359,456)						(359,456)
Dividends on preferred shares / Distributions to preferred unitholders	(38,103)							(38,103)						(38,103)						(38,103)
Preferred share issuance costs	(15,149)				$ (663)			(14,486)										$ (663)								$ (14,486)	$ (15,149)	$ (14,486)
Common shares issued: / Class A Units issued to Vornado
Upon redemption of Class A units, at redemption value, shares						201													201
Upon redemption of Class A units, at redemption value, value	14,089					$ 8	14,081							14,089					$ 14,089
Under Vornado's employees' share option plan, shares						77													77
Under Vornado's employees' share option plan, value	4,226					$ 3	4,223							4,226					$ 4,226
Under Vornado's dividend reinvestment plan, shares						15													15
Under Vornado's dividend reinvestment plan, value	1,036					$ 1	1,035							1,036					$ 1,036
Contributions:
Contributions			46,942	14,577								46,942	14,577			46,942	14,577							46,942	14,577
Distributions:
Distributions	(23,867)		(12,665)	$ (28,173)								$ (12,665)	$ (28,173)			$ (12,665)	$ (28,173)							$ (12,665)	$ (28,173)
Conversion of Series A preferred shares to common shares / Conversion of Series A preferred units to Class A units, shares					(1)	2												(1)	2
Conversion of Series A preferred shares to common shares / Conversion of Series A preferred units to Class A units, value	0				$ (31)	$ 0	31							0				$ (31)	$ 31
Deferred compensation shares and options, shares						7													7
Deferred compensation shares and options, value	750					$ 0	871	(121)						750					$ 871	(121)
Reduction in unrealized net gain on available-for-sale securities	0													0
Pro rata share of amounts reclassified related to a nonconsolidated subsidiary	0													0
Pro rata share of other comprehensive income (loss) of nonconsolidated subsidiaries	989									989				989								989
Increase in value of interest rate swaps	13,789									13,789				13,789								13,789
Unearned 2015 Out-Performance Plan awards acceleration	9,046						9,046							9,046					9,046
Adjustments to carry redeemable Class A units at redemption value	57,970						57,970							57,970					57,970
Redeemable noncontrolling interests' share of above adjustments	(913)									(913)				(913)								(913)
Other, value	544						548	(3)			(1)			544					$ 548	(3)			(1)
Ending balance, shares at Sep. 30, 2018					36,799	190,286												36,799	190,286
Ending balance, value at Sep. 30, 2018	5,037,509				$ 891,294	$ 7,589	7,580,463	(4,135,602)		34,173	659,592			5,037,509				$ 891,294	$ 7,588,052	(4,135,602)		34,173	659,592
Beginning balance, value at Jun. 30, 2018										33,351
Net income (loss) attributable to Vornado / Vornado Realty L.P.	203,179													215,850
Net income attributable to redeemable partnership units	(12,671)
Net income attributable to noncontrolling interests in consolidated subsidiaries	3,312		$ 558											3,312
Distributions:
Reduction in unrealized net gain on available-for-sale securities	0													0
Pro rata share of amounts reclassified related to a nonconsolidated subsidiary	0													0
Pro rata share of other comprehensive income (loss) of nonconsolidated subsidiaries	253													253
Ending balance, shares at Sep. 30, 2018					36,799	190,286												36,799	190,286
Ending balance, value at Sep. 30, 2018	$ 5,037,509				$ 891,294	$ 7,589	$ 7,580,463	$ (4,135,602)		$ 34,173	$ 659,592			$ 5,037,509				$ 891,294	$ 7,588,052	$ (4,135,602)		$ 34,173	$ 659,592