Subsequent Events (Details) - Subsequent Event - Joint Venture	Oct. 31, 2016
Subsequent Events [Line Items]
Subsequent Event, Description	our Board of Trustees approved the tax-free spin-off of our Washington, DC business and we entered into a definitive agreement to merge it with the business and certain select assets of The JBG Companies (“JBG”), a Washington, DC real estate company
Pro Rata Distribution
Subsequent Events [Line Items]
Initial Form 10 registration statement relating to the spin-off is expected to be filed with the SEC	Fourth quarter of 2016
Distribution and combination are expected to be completed	Second quarter of 2017
Vornado Trust Realty and Vornado Realty LP | Pro Rata Distribution
Subsequent Events [Line Items]
Pro rata basis of distribution	1:2