Supplemental Cash Flow Information - Details of Supplemental Cash Flow Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash paid during the period for:
Income taxes, net	$ 21,324	$ 25,395	$ 52,565
Interest, net	2,101	1,609	1,048
Non-Cash Transaction Information:
Shares tendered in payment of exercise price of stock options	63	0	84
Employee stock purchase plan	669	578	699
Equipment acquired under capital leases	1,153	1,470	313
Unsettled repurchases of common stock	935	1,012	1,425
Acquisition of fixed assets through accounts payable	12	41	19
Contingent consideration for acquisition	$ 0	$ 0	$ 477