Components of Rental Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Cash rental income	$ 44,220	$ 32,555	$ 123,982	$ 95,111
Straight-line rental income (expense), net	1,727	(1,227)	3,420	2,998
Rental income from intangible amortization, net	132	365	539	1,097
Total rental income	$ 46,079	$ 31,693	$ 127,941	$ 99,206