Commitments and Contingencies (Details) (USD $)						9 Months Ended					9 Months Ended
	Sep. 30, 2012	Sep. 30, 2012 NBCR Losses [Member]	Sep. 30, 2012 Earthquake California Properties [Member]	Sep. 30, 2012 All Risk And Rental Value [Member]	Sep. 30, 2012 General Liability [Member]	Sep. 30, 2012 PPIC [Member] NBCR Losses [Member]	Sep. 30, 2012 Stop & Shop [Member]	Jan. 12, 2012 Stop & Shop [Member]	Dec. 16, 2011 Stop & Shop [Member]	Feb. 28, 2011 Stop & Shop [Member]	Sep. 30, 2012 Cleveland Medical Mart [Member]
Insurance [Abstract]
Insurance limit per occurrence		$ 2,000,000,000	$ 180,000,000	$ 2,000,000,000	$ 300,000,000
Vornado deductible, percentage of property value			5.00%
Vornado deductible, annual aggregate			180,000,000
Insurance deductible						3,200,000
Insurance Deductible Percentage Of Balance Of Covered Loss						15.00%
Federal government deductible, percentage of balance of a covered loss		85.00%
Other Commitments And Contingencies [Abstract]
Guarantees and master leases	267,090,000
Outstanding letters of credit	22,576,000
Commitments to Fund Improvements											11,500,000
Commitment to fund additional capital to partially owned entities	244,463,000
Commitment Funded During Period											1,100,000
Litigation [Abstract]
Stop & Shop complaint regarding rent allocated to East Brunswick, Jersey City, Middletown, Union, and Woodbridge leases							5,000,000
Accounts Receivable, Gross							46,400,000
Stop & Shop judgement in our favor to pay us the unpaid annual rent accrued									56,597,000	37,422,000
Stop & Shop recovery action of annual rent commenced by Vornado								2,500,000
Maximum Reasonably Possible Loss							$ 46,400,000