Combined Summary of the Operating Results of the Entities Accounted for using the Equity Method (Detail) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Schedule of Equity Method Investments [Line Items]
Rental and other income	$ 38,632	$ 26,652	$ 76,454	$ 52,830
Operating and other expenses	(17,090)	(11,862)	(34,644)	(24,802)
Interest expense, net	(12,478)	(9,498)	(24,779)	(18,591)
Depreciation expense	(11,737)	(8,605)	(23,339)	(17,252)
Net loss	$ (2,673)	$ (3,313)	$ (6,308)	$ (7,815)