Commitments and Contingencies (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 16, 2011	Nov. 07, 2011
Guarantees and master leases	$ 283,625,000
Outstanding letters of credit	22,085,000
Development and Operating Period	17 years
NBCR Losses [Member]
Federal government deductible, percentage of balance of a covered loss	85.00%
Insurance limit per occurrence	2
Earthquake California Properties [Member]
Vornado deductible, annual aggregate	180,000,000
Insurance limit per occurrence	180,000,000
Vornado deductible, percentage of property value	5.00%
All Risk And Rental Value [Member]
Insurance limit per occurrence	2.0
General Liability [Member]
Insurance limit per occurrence	300,000,000
PPIC [Member] | NBCR Losses [Member]
Insurance deductible	3,200,000
Insurance Deductible Percentage Of Balance Of Covered Loss	15.00%
Central Park South 220 [Member]
Commitment to fund additional capital to partially owned entities	288,799,000
Stop & Shop [Member]
Stop & Shop complaint regarding annual rent collected pursuant to Master Agreement and Guaranty	5,000,000
Stop & Shop judgement in our favor to pay us the unpaid annual rent accrued		56,597,000	37,422,000
Accounts Receivable, Gross	41,983,000
Allowance for Doubtful Accounts Receivable	23,521,000
Loss Contingency, Opinion of Counsel	41,983,000
Stop & Shop recovery action of annual rent commenced by Vornado	$ 2,500,000