Discontinued Operations and Disposition of Real Estate and Real Estate Investments - Additional Information (Detail)	12 Months Ended	36 Months Ended
	Dec. 31, 2012 Property	Dec. 31, 2012 Property	Dec. 31, 2011 Property	Dec. 31, 2010 Property
Discontinued Operations [Line Items]
Number of properties sold	29
Number of assets held for sale			1
Number of properties included in discontinued operations		120
Number of disposed properties previously included in shopping center segment		88
Number of disposed properties previously included in other investments segment		6
Number of properties included in other investments segment		0
Other properties deconsolidated for accounting purposes	26	26	26	26