Noncontrolling Interests and Redeemable Noncontrolling Interests (Details 3) (USD $) In Thousands, except Share data, unless otherwise specified			1 Months Ended	3 Months Ended			6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Mar. 31, 2012 Reedemable Non Controlling Interest [Member]	Jun. 30, 2012 Reedemable Non Controlling Interest [Member]	Mar. 31, 2012 Reedemable Non Controlling Interest [Member]	Dec. 31, 2011 Reedemable Non Controlling Interest [Member]	Jun. 30, 2012 PJV Units [Member]	Jun. 30, 2011 PJV Units [Member]	Jun. 30, 2012 Noncontrolling Interest [Member]	Dec. 31, 2011 Noncontrolling Interest [Member]	Jun. 30, 2012 Third Party Interests [Member]	Dec. 31, 2011 Third Party Interests [Member]	Jun. 30, 2012 Other Consolidated Subsidiaries [Member]	Dec. 31, 2011 Other Consolidated Subsidiaries [Member]	Jun. 30, 2012 Outlet Shoppes at Atlanta [Member]	Apr. 17, 2012 Outlet Shoppes at Gettysburg [Member]	Jun. 30, 2012 Outlet Shoppes at El Paso [Member]	Apr. 20, 2012 Outlet Shoppes at El Paso [Member]
Noncontrolling Interest [Line Items]
Percentage of Equity Interest in Real Estate Property																50.00%		75.00%
Noncontrolling Interest, Ownership Percentage by Parent															75.00%
Redeemable Noncontrolling Interest, Units Converted to Common				9,757,100
Redeemable Noncontrolling Interest, Equity, Carrying Amount	$ 461,995	$ 456,105		$ 38,218		$ 32,271					$ 32,063	$ 26,036	$ 6,155	$ 6,235
Non-controlling interests									164,148	207,113	142,222	202,833	21,926	4,280			11,819
Payments for Repurchase of Redeemable Noncontrolling Interest				3,475	6,359
Redeemable Noncontrolling Interest, Conversion Rights Exercised for Cash			194,572		431,380
Increase (Decrease) in Redeemable Noncontrolling Preferred Joint Venture Interest
Redeemable noncontrolling preferred joint venture interest	423,777	423,834					423,834	423,834
Net income attributable to redeemable noncontrolling preferred joint venture interest							10,286	10,228
Distributions to redeemable noncontrolling preferred joint venture interest							(10,343)	(10,286)
Redeemable noncontrolling preferred joint venture interest	$ 423,777	$ 423,834					$ 423,777	$ 423,776