Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 1,057	$ 17,762	$ (8,681)
Other comprehensive income (loss)
Foreign currency translation adjustment	5,105	(27,622)	(13,318)
Pension liability, net of tax expense (benefit) of ($95) in 2016, $113 in 2015 and ($448) in 2014	(169)	200	(797)
Total other comprehensive income (loss)	4,936	(27,422)	(14,115)
Comprehensive income (loss)	$ 5,993	$ (9,660)	$ (22,796)