Interim Financial Statements (Operating Partnership) (Details) - shares	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
The Operating Partnership [Abstract]
Number of urban and suburban shopping centers in the Company's owned portfolio	19
Number of states in which Company operates	10
Number Of Classes Of Preferred Stock	three
Common stock, shares outstanding	60,258,750		63,324,409
Number Of Classes Of Preferred Equity	two
Noncontrolling Interest, Ownership Percentage by Parent	71.00%
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest	71.00%	72.00%
Units of Partnership Interest, Amount	85,320,909
Number Of Operating Partnership Units Outstanding Owned By Company	60,258,750
Series J Preferred Stock [Member]
The Operating Partnership [Abstract]
Dividend rate (in hundredths)	6.50%
Preferred Stock, Shares Outstanding	7,700,000		7,700,000
Series K Preferred Stock [Member]
The Operating Partnership [Abstract]
Dividend rate (in hundredths)	6.25%
Preferred Stock, Shares Outstanding	6,800,000		6,800,000
Series B Preferred Stock [Member]
The Operating Partnership [Abstract]
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, Shares Outstanding	25,044,939		25,117,000