Investment in Real Estate - Net Non-Cash Impairment Charges (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Impairment Charges [Line Items]
Impairment of Real Estate	$ 1,246	$ (2,661)	$ 194,552
Operating Properties-Held for Sale and Sold Assets [Member]
Impairment Charges [Line Items]
Impairment of Real Estate	1,410	4,973	66,026
Impairment-Discontinued Operations [Member]
Impairment Charges [Line Items]
Impairment of Real Estate	1,410	4,973	66,026
Land Parcels Sold Assets [Member]
Impairment Charges [Line Items]
Impairment of Real Estate		(5,879)	8,275
Operating Properties - Held for Use [Member]
Impairment Charges [Line Items]
Impairment of Real Estate	(164)	(514)	105,826
Land Parcels - Held for Use [Member]
Impairment Charges [Line Items]
Impairment of Real Estate		(1,241)	14,425
Impairment - Continuing Operations [Member]
Impairment Charges [Line Items]
Impairment of Real Estate	$ (164)	$ (7,634)	$ 128,526