Redeemable Noncontrolling Interests / Redeemable Partnership Units (Activity of Redeemable Noncontrolling Interests) (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Redeemable Noncontrolling Interests Rollforward
Balance as of December 31			$ 984,937	$ 1,278,446
Net income	$ 12,671	$ (1,878)	18,992	9,057
Other comprehensive income			913	188
Distributions			(23,867)	(25,663)
Other, net			15,666	30,168
Balance as of June 30	$ 924,582	$ 970,704	924,582	970,704
Class A Unit
Redeemable Noncontrolling Interests Rollforward
Redemption of Class A units for Vornado common shares, at redemption value			(14,089)	(34,564)
Adjustments to carry redeemable Class A units at redemption value (including $224,069 attributable to the spin-off of JBGS)			(57,970)	$ (286,928)
JBGS \| Class A Unit
Redeemable Noncontrolling Interests Rollforward
Adjustments to carry redeemable Class A units at redemption value (including $224,069 attributable to the spin-off of JBGS)			$ 224,069

Decrease in noncontrolling interest balance from payment of dividends or other distributions by the non-wholly owned subsidiary or partially owned entity, included in the consolidation of the parent entity, to the noncontrolling interest holders.

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Decrease in noncontrolling interest (for example, but not limited to, redeeming or purchasing the interests of noncontrolling shareholders, issuance of shares (interests) by the non-wholly owned subsidiary to the parent entity for other than cash, and a buyback of shares (interest) by the non-wholly owned subsidiary from the noncontrolling interests).

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Amount of Net Income (Loss) attributable to redeemable noncontrolling interest.

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Amount after tax of other comprehensive income (loss) attributable to noncontrolling interests.

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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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Adjustments to reflect redeemable Class A Operating Partnership units

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Other Net Attributable To Redeemable Noncontrolling Interest

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