Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net loss	$ (17,620)	$ (9,205)
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustment	(461)	1,437
Defined benefit plans, net of tax:
Amortization of prior service cost, net of tax provision of $5 for the three months ended March 31, 2018	0	19
Other comprehensive income (loss), net of tax	(461)	1,456
Comprehensive loss	$ (18,081)	$ (7,749)