Assets Held for Sale and Discontinued Operations - Income Attributable to Discontinued Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Discontinued Operations And Disposal Groups [Abstract]
Rental income and recoveries	$ 801	$ 23,910	$ 8,602	$ 88,245
Rental expenses	(575)	(7,364)	(3,368)	(26,840)
Depreciation and amortization	(353)	(8,148)	(3,394)	(30,862)
Interest expense		(344)	(87)	(1,281)
Income (loss) attributable to disposed properties and assets held for sale	(127)	8,054	1,753	29,262
Net gains (losses) on dispositions, net of taxes	40,297	(4,049)	59,598	17,074
Impairment Charges		(27,409)		(27,409)
Total discontinued operations	$ 40,170	$ (23,404)	$ 61,351	$ 18,927