Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (8,639)	$ 4,384
Other comprehensive (loss) income - net of tax:
Adjustment to accrued pension liability	499	729
Change in unrealized net (loss) gain on foreign currency	(1,473)	3,235
Unrealized gain (loss) on cash flow hedge derivatives	36	(348)
Other comprehensive (loss) income	(938)	3,616
Total comprehensive (loss) income	$ (9,577)	$ 8,000