Income Taxes - Components of the Income Tax Provision (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Federal	$ 2,587	$ 6,094	$ 5,103
State	1,060	2,330	1,252
Foreign	2,159	2,032	1,954
Total current	5,806	10,456	8,309
Deferred:
Federal	5,550	2,719	(723)
State	700	59	(232)
Foreign	175	(176)	(30)
Total deferred	6,425	2,602	(985)
Income tax provision	$ 12,231	$ 13,058	$ 7,324