CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (14,516)	$ 11,107	$ 12,813
Currency translation adjustments, net of income tax	16,739	(4,700)	(13,166)
Comprehensive income (loss)	$ 2,223	$ 6,407	$ (353)