Redeemable Noncontrolling Interests (Activity of Redeemable Noncontrolling Interests) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Redeemable Noncontrolling Interests Rollforward
Beginning balance			$ 888,915
Net income (loss)	$ 3,884	$ 22,637	(10,090)	$ 197,354
Other comprehensive loss	(520)	(650)	(3,498)	(3,732)
Ending balance	693,751		693,751
Partnership Interest
Redeemable Noncontrolling Interests Rollforward
Beginning balance	624,804	862,062	888,915	783,562
Net income (loss)	3,884	22,637	(10,090)	197,354
Other comprehensive loss	(520)	(650)	(3,498)	(3,732)
Distributions	(7,332)	(8,852)	(25,330)	(25,788)
Other, net	5,776	5,363	27,958	34,700
Ending balance	599,469	854,333	599,469	854,333
Partnership Interest | Class A Unit
Redeemable Noncontrolling Interests Rollforward
Redemption of Class A units for Vornado common shares, at redemption value	(3,586)	(1,999)	(6,050)	(8,128)
Redeemable Class A unit measurement adjustment	(23,557)	$ (24,228)	(272,436)	$ (123,635)
Subsidiary
Redeemable Noncontrolling Interests Rollforward
Beginning balance	94,112		0
Net income (loss)	171		307
Contributions	0		92,400
Other, net	(1)		1,575
Ending balance	$ 94,282		$ 94,282