Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income		$ 59,415	$ 135,601	$ 121,380
Other comprehensive income (loss), net of tax
Unrealized gain (loss) hedging activities, net of tax (1)	[1]	299	(342)	847
Unrealized (loss) gain on hedging activities, tax		232	(42)	227
Foreign currency translation adjustments, net of tax (2)	[2]	83,404	(48,367)	(54,232)
Foreign currency translation adjustment, tax		610	(833)	(1,777)
Defined benefit pension and other postretirement benefits, net of tax (3)	[3]	10,726	(8,867)	9,586
Defined benefit pension and other postretirement benefits, tax		4,469	(4,687)	3,916
Total other comprehensive income (loss), net of tax		94,429	(57,576)	(43,799)
Total comprehensive income		$ 153,844	$ 78,025	$ 77,581

[1] Net of tax of $232, $(42) and $227 for the years ended December 31, 2017, 2016 and 2015, respectively.

[2] Net of tax of $610, $(833) and $(1,777) for the years ended December 31, 2017, 2016 and 2015, respectively.

[3] Net of tax of $4,469, $(4,687) and $3,916 for the years ended December 31, 2017, 2016 and 2015, respectively.