Interim Financial Statements (Details)	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Schedule of Equity Method Investments [Line Items]
Number of urban and suburban shopping centers in the Company's owned portfolio	25
Number of states in which Company operates	13
Number Of Classes Of Preferred Stock	three
Common stock, shares outstanding	63,524,788	63,310,148
Westfarms [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage (in hundredths)	79.00%	79.00%
Series J Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Dividend rate (in hundredths)	6.50%
Preferred Stock, Non-Participating, Convertible, Shares Outstanding	7,700,000	7,700,000
Series K Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Dividend rate (in hundredths)	6.25%
Preferred Stock, Non-Participating, Convertible, Shares Outstanding	6,800,000
Series B Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Units of Partnership Interest, Terms of Conversion	one share of nonparticipating Series B Preferred Stock per each Operating Partnership unit
Preferred Stock, voting rights	one vote per share
Convertible Preferred Stock, Terms of Conversion	ratio of 14,000 shares of Series B Preferred Stock for one share of common stock
Preferred Stock, Non-Participating, Convertible, Shares Outstanding	25,159,072	25,327,699