Fair Value Measurements (Details) (USD $)	Jun. 30, 2014	Dec. 31, 2013
Financial Assets And Liabilities Measured At Fair Value
Marketable securities	$ 35,729,000	$ 31,522,000
Interest rate cap (included in other assets)	47,000
Total assets	35,776,000
Liabilities measured at fair value	0	0
Carrying Reported Amount Fair Value Disclosure [Member]
Assets
Cash Equivalents	303,433,000	184,796,000
Liabilities
Mortgages Payable Fair Value Disclosure	1,034,289,000	1,049,959,000
Leasing commissions (included in amounts due to Vornado)	41,279,000	42,924,000
Total liabilities not measured at fair value	1,075,568,000	1,092,883,000
Estimate Of Fair Value Fair Value Disclosure [Member]
Assets
Cash Equivalents	303,433,000	184,796,000
Liabilities
Mortgages Payable Fair Value Disclosure	1,037,000,000	1,072,000,000
Leasing commissions (included in amounts due to Vornado)	41,000,000	43,000,000
Total liabilities not measured at fair value	1,078,000,000	1,115,000,000
Fair Value, Inputs, Level 1 [Member]
Financial Assets And Liabilities Measured At Fair Value
Marketable securities	35,729,000	31,522,000
Interest rate cap (included in other assets)	0
Total assets	35,729,000
Fair Value, Inputs, Level 2 [Member]
Financial Assets And Liabilities Measured At Fair Value
Marketable securities	0	0
Interest rate cap (included in other assets)	47,000
Total assets	47,000
Fair Value, Inputs, Level 3 [Member]
Financial Assets And Liabilities Measured At Fair Value
Marketable securities	0	0
Interest rate cap (included in other assets)	0
Total assets	$ 0