Subsequent Events (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended			0 Months Ended	3 Months Ended	1 Months Ended	0 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Feb. 14, 2014 Subsequent Event [Member] Retail NY Hicksville (Broadway Mall) [Member]	Dec. 31, 2013 Subsequent Event [Member] Retail NY Hicksville (Broadway Mall) [Member]	Mar. 31, 2014 Subsequent Event [Member] Retail Springfield Mall [Member]	Jan. 31, 2014 New York Manhattan 220 Central Park South Site [Member] Subsequent Event [Member] Extensions
Debt Instrument [Line Items]
Notes And Loans Payable	$ 8,331,993	$ 8,599,222					$ 600,000
Debt Instrument, Description of Variable Rate Basis							LIBOR
Debt Instrument, Basis Spread on Variable Rate							2.75%
Debt Instrument Maturity Date (String)							January 2016
Number Of Extensions Available							3
Length Of Extension Available							1 year
Sale Price Of Real Estate Property						465,000
Anticipated net proceeds from the sale of real estate				94,000		340,000
Value of operating partnership units received in sale of real estate						125,000
Non-cash impairment charges					13,443
Cash proceeds from the sale of real estate				92,000
Development And Project Management Expenses	$ 32,210	$ 226,619	$ 145,824