CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 74,564	$ (3,519)	$ 34,004
Other comprehensive income (loss), before tax:
Change in foreign currency translation adjustments	(10,278)	(25,841)	(26,674)
Unrealized gain (loss) on derivatives
Unrealized derivative gain (loss) arising during period	1,871	(25)	(206)
Less: Reclassification adjustments for losses included in net loss	0	(923)	(1,747)
Unrealized gain on derivatives	1,871	898	1,541
Defined benefit pension plan
Defined benefit pension plan - net (loss) gain arising during period	(45)	904	1,672
Total other comprehensive loss, before tax	(8,452)	(24,039)	(23,461)
Income tax expense related to items in other comprehensive loss	(800)	(375)	(954)
Total other comprehensive loss, net of tax	(9,252)	(24,414)	(24,415)
Comprehensive income (loss), net of tax	$ 65,312	$ (27,933)	$ 9,589