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)	$ (34,638)	$ 6,510	$ 10,350
Foreign currency adjustment	(758)	(1,875)	(2,274)
Change in pension loss, net of taxes of $71, $327 and $(428), in 2016, 2015 and 2014, respectively	(1,365)	2,828	(4,614)
Other comprehensive income (loss)	(2,123)	953	(6,888)
Comprehensive income (loss)	$ (36,761)	$ 7,463	$ 3,462