Lease Obligations - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Disclosure Lease Obligations Additional Information [Abstract]
Rent expense related to operating leases	$ 2,500	$ 1,700	$ 1,800
Operating Leases, Future Minimum Payments Due, Next Twelve Months	1,400
Operating Leases, Future Minimum Payments, Due in Two Years	1,100
Operating Leases, Future Minimum Payments, Due in Three Years	848
Operating Leases, Future Minimum Payments, Due in Four Years	688
Operating Leases, Future Minimum Payments, Due in Five Years	462
Future minimum payments under current lease agreements, thereafter	2,300
Future minimum payments under current lease agreements, total	6,800
Payments to Acquire Capital Leases		$ 1,500	$ 1,100
Capital Leases, Future Minimum Payments Due, Next Twelve Months	1,500
Capital Leases, Future Minimum Payments Due in Five Years	625
Capital Leases, Future Minimum Payments Due	$ 3,600