Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 22,745	$ 12,988	$ 83,631	$ 45,457
OTHER COMPREHENSIVE INCOME (LOSS)
Foreign currency translation adjustments	(92)	299	(392)	749
COMPREHENSIVE INCOME	$ 22,653	$ 13,287	$ 83,239	$ 46,206