Fair Value Measurements - Assets and Liabilities Carried at Fair Value Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Interest rate swaps	$ (14,892)	$ (13,341)
Interest Rate Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Interest rate swaps	(14,892)	(13,341)
Interest Rate Swap [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Interest rate swaps	$ (14,892)	$ (13,341)