Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Net income (loss)	$ 16,430	$ 3,949	$ (32,389)
Other comprehensive income (loss), before tax:
Foreign currency translation adjustments	1,732	(7,168)	(8,592)
Other comprehensive income (loss), before tax	1,732	(7,168)	(8,592)
Income tax expense (benefit) related to components of other comprehensive income (loss)	(12)	21	341
Other comprehensive income (loss), net of tax	1,720	(7,147)	(8,251)
Comprehensive income (loss)	$ 18,150	$ (3,198)	$ (40,640)