Fair Value Measurements - Assets Measures at Fair Value on a Recurring Basis by Level within Fair Value Hierarchy (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Interest rate swap asset	$ 4,752	$ 5,594
Interest Rate Swap Liability	(785)	(2,045)
Significant Other Observable Inputs (Level 2)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Interest rate swap asset	4,752	5,594
Interest Rate Swap Liability	$ (785)	$ (2,045)