Basis of Presentation and Significant Accounting Policies (Estimated Taxable Income) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Net income attributable to Vornado common shareholders	$ 100,494	$ 190,645	$ 111,534	$ (17,841)	$ 27,319	$ (29,026)	$ 115,972	$ 47,752	$ 384,832	$ 162,017	$ 823,606
Depreciation and amortization									234,325	213,083	302,092
Tangible property regulations									(86,040)	0	0
Sale of real estate and other capital transactions									31,527	11,991	(39,109)
Vornado stock options									(22,992)	(6,383)	(3,593)
Earnings of partially owned entities									15,711	(3,054)	(149,094)
Impairment losses									(11,260)	(49,062)	(170,332)
Straight-line rent adjustments									(7,133)	(36,696)	(137,941)
Tax expense related to the reduction of our taxable REIT subsidiaries' deferred tax assets									0	32,663	0
Net gain on extinguishment of Skyline properties debt									0	0	(457,970)
Other, net									18,956	25,057	9,121
Estimated taxable income (unaudited)									$ 580,446	$ 447,740	$ 517,444