Unaudited Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Statement of Comprehensive Income [Abstract]
Net loss	$ (83,528)	$ (4,221)	$ (104,122)	$ (3,299)
Foreign currency translation adjustment	3,850	(1,178)	10,406	1,872
Foreign currency hedge	(483)	(104)	(1,598)	(347)
Amortization of net actuarial loss on defined benefit pension plans	19	0	53	0
Other comprehensive income (loss), before tax	3,386	(1,282)	8,861	1,525
Tax (provision) benefit attributable to other comprehensive income (loss)	(1,065)	287	(2,295)	(1,031)
Other comprehensive income (loss), net of tax	2,321	(995)	6,566	494
Total comprehensive loss	$ (81,207)	$ (5,216)	$ (97,556)	$ (2,805)