Leases - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating Leased Assets [Line Items]
Operating lease expiration year	2023
Rent expense	$ 6,700	$ 7,200	$ 6,700
Related Party Transaction
Operating Leased Assets [Line Items]
Rent expense	$ 330	$ 1,800	$ 1,700