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Impairment Charges and Impairment of Joint Venture Investments - Impairment Charges on Consolidated Assets (Parenthetical) (Detail) (USD $)
 3 Months Ended 12 Months Ended
Dec. 31, 2010
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Investment Securities [Line Items]        
Company's proportionate share of impairment related to land under development for consolidated joint ventures     $ 50,400,000 $ 41,900,000
Impairment charge related to abandoned development project 19,300,000     19,300,000
Company's share of impairment of assets formerly occupied by major tenant       16,500,000
Impairment of unconsolidated joint venture investments   26,671,000 2,921,000 227,000
12 Months Ended Coventry II DDR Montgomery Farm LLC [Member]
        
Investment Securities [Line Items]        
Impairment of unconsolidated joint venture investments   $ 26,100,000