Acquisitions (Details) (Subsequent Event [Member], USD $)		0 Months Ended
	Jul. 05, 2012 Fifth Avenue 666 [Member]	Jul. 05, 2012 Fifth Avenue 666 [Member] Retail Units [Member] ft sqft	Jul. 05, 2012 Fifth Avenue 666 [Member] Retail Units [Member] Fee Simple [Member] sqft	Jul. 05, 2012 Fifth Avenue 666 [Member] Retail Units [Member] Leasehold Interest [Member] sqft	Jun. 30, 2012 Marriott Marquis Time Square Hotel [Member] Hotel [Member]
Acquisitions [Line Items]
Business Acquisition, Description of Acquired Entity		we entered into an agreement to acquire a retail condominium located at 666 Fifth Avenue at 53rd Street for $707,000,000. The property has 126 feet of frontage on Fifth Avenue and contains 114,000 square feet, 39,000 square feet in fee and 75,000 square feet by long-term lease from the 666 Fifth Avenue office condominium, which is 49.5% owned by Vornado
Square Footage Of Real Estate Property		114,000	39,000	75,000
Number of Units in Real Estate Property					1,900
Business Acquisition Cost Of Acquired Entity Purchase Price		$ 707,000,000
Equity method ownership percentage	49.50%
Redevelopment Expenditures Planned					$ 140,000,000
Length of storefront in feet		126