Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement [Abstract]
Net income (loss)	$ 9,600	$ (1,700)
Net pension adjustments, net of tax:
Liability adjustments for defined benefit pension plans
Reclassification of adjustment for defined benefit plans recorded in net loss	100	100
Total net pension adjustments	100	100
Net foreign currency translation:
Unrealized foreign currency translation losses		(300)
Total net foreign currency translation		(300)
Total other comprehensive income (loss), net of tax	100	(200)
Comprehensive income (loss)	$ 9,700	$ (1,900)