Investments in and Advances To Joint Ventures (Details Textual) (USD $)	3 Months Ended			1 Months Ended			3 Months Ended
	Mar. 31, 2012 Property Store	Mar. 31, 2011 Property Store	Dec. 31, 2011	Jan. 31, 2012 Blackstone Group [Member] Shopping_centers	Mar. 31, 2012 Unconsolidated Joint Venture [Member] Shopping_centers	Dec. 31, 2011 Unconsolidated Joint Venture [Member] Shopping_centers	Mar. 31, 2012 Sonae Sierra Brasil [Member]
Schedule of Equity Method Investments [Line Items]
Shopping centers owned	420	476			172	177
Ownership interest of joint venture partner				95.00%
Investments in and advances to joint ventures	$ 363,706,000		$ 353,907,000	$ 150,000,000
Value of shopping centers				1,400,000,000
Debt to be assumed.				640,000,000
Anticipated New financings				305,000,000
Remaining interest owned by company				5.00%
Preferred stock dividend rate				10.00%
Percentage of additional shares acquired							30.00%
Percentage of shares exchanged for acquisition							22.00%
Amount paid for acquisition of shopping penha							29,000,000
Larger interest in shopping center after asset swap							60.00%
Smaller interest in shopping center after asset swap							51.00%
Number of shopping center properties owned under various unconsolidated joint ventures				46
Equity Investments in Joint Ventures (Textual) [Abstract]
Company's proportionate share of impairment charge	500,000
Number of unconsolidated joint venture properties sold	1	2
Number of unconsolidated joint ventures that sold properties	1	2
Company's proportionate share of loss on disposition of assets by unconsolidated joint ventures	0	1,900,000
Amounts receivable from joint ventures	2,600,000
Gain on partial sale of ownership interest	$ 2,800,000