Noncontrolling Interests and Redeemable Noncontrolling Interests (Details 3) (USD $)			3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2013 PJV Units [Member]	Mar. 31, 2012 PJV Units [Member]	Mar. 31, 2013 Reedemable Non Controlling Interest [Member]	Dec. 31, 2012 Reedemable Non Controlling Interest [Member]	Mar. 31, 2013 Noncontrolling Interest [Member]	Dec. 31, 2012 Noncontrolling Interest [Member]	Mar. 31, 2013 Third Party Interests [Member]	Dec. 31, 2012 Third Party Interests [Member]	Mar. 31, 2013 Other Consolidated Subsidiaries [Member]	Dec. 31, 2012 Other Consolidated Subsidiaries [Member]	Mar. 31, 2013 Outlet Shoppes at Gettysburg [Member]	Apr. 08, 2013 Kirkwood Mall [Member]	Mar. 31, 2013 Kirkwood Mall [Member]	Mar. 31, 2013 Outlet Shoppes at El Paso [Member]	Mar. 31, 2013 Triangle Town Member LLC [Member]
Noncontrolling Interest [Line Items]
Percentage of Equity Interest in Real Estate Property													50.00%		49.00%	75.00%	50.00%
Redeemable Noncontrolling Interest, Equity, Carrying Amount	$ 467,334,000	$ 464,082,000			$ 43,615,000	$ 40,248,000			$ 37,574,000	$ 33,835,000	$ 6,041,000	$ 6,413,000
Non-controlling interests							197,843,000	192,404,000	135,281,000	128,907,000	62,562,000	63,497,000			0.51
Business Acquisition, Purchase Price Allocation, Liabilities Assumed														40,368,000
Increase (Decrease) in Redeemable Noncontrolling Preferred Joint Venture Interest
Redeemable noncontrolling preferred joint venture interest	423,719,000	423,834,000	423,834,000	423,834,000
Net income attributable to redeemable noncontrolling preferred joint venture interest			5,085,000	5,144,000
Distributions to redeemable noncontrolling preferred joint venture interest			(5,200,000)	(5,201,000)
Redeemable noncontrolling preferred joint venture interest	$ 423,719,000	$ 423,834,000	$ 423,719,000	$ 423,777,000