Depreciation and Amortization - Depreciation and Amortization Expense for Property and Equipment and Intangible Assets (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Property, Plant and Equipment [Line Items]
Total depreciation expense	$ 5,641	$ 5,245
Operating Expenses [Member]
Property, Plant and Equipment [Line Items]
Total depreciation expense	5,543	5,130
Corporate General and Administrative Expenses [Member]
Property, Plant and Equipment [Line Items]
Total depreciation expense	$ 98	$ 115