Commitments and Contingencies - Total Rent Expense under Operating Lease (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Leased Assets [Line Items]
Rent expense under operating leases	$ 11,580	$ 9,362	$ 7,871
Cost of Sales [Member]
Operating Leased Assets [Line Items]
Rent expense under operating leases	848	855	733
Administrative [Member]
Operating Leased Assets [Line Items]
Rent expense under operating leases	$ 10,732	$ 8,507	$ 7,138