CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 20,896	$ 5,377	$ 47,928	$ 20,305
Foreign currency translation adjustment	12,591	(5,729)	16,730	5,197
Derivative instruments designated as cash flow hedges:
Unrealized gain (loss) on derivative instruments held at period end, net of tax (Note 6)	(321)	5	(435)	11
Unrealized (gain) loss reclassified into earnings (Note 6)	107	0	107	0
Accumulated other comprehensive income (loss) pension and post-retirement benefits:
Actuarial net gain (loss) incurred in fiscal year, net of tax (Note 6)	334		334
Pension and postretirement benefit plans reclassified into earnings, net of tax (Note 6):
Amortization of loss, net of tax (Note 6)	6	36	36	71
Other comprehensive income (loss)	12,717	(5,688)	16,772	5,279
Comprehensive income (loss)	$ 33,613	$ (311)	$ 64,700	$ 25,584