CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 16,065	$ 12,546	$ 36,370	$ 39,742
Foreign currency translation adjustment	1,408	(2,067)	6,605	(21,317)
Derivative instruments designated as cash flow hedges:
Unrealized gain (loss) on derivative instruments held at period end, net of tax (Note 6)		(19)		(179)
Unrealized gain (loss) reclassified into earnings (Note 6)	0	(1)	11	93
Pension and postretirement benefit plans reclassified into earnings, net of tax (Note 6):
Amortization of loss	34	277	105	808
Other comprehensive income (loss)	1,442	(1,810)	6,721	(20,595)
Comprehensive income (loss)	$ 17,507	$ 10,736	$ 43,091	$ 19,147