Consolidated Statement of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net Income	$ 19,600	$ 14,850	$ 43,920	$ 21,840
Other comprehensive income
Defined benefit pension and postretirement plans	2,650	160	2,850	330
Foreign currency translation	(6,450)	1,930	(4,090)	3,730
Derivative instruments	5,710	(400)	1,670	(20)
Total other comprehensive income (loss)	1,910	1,690	430	4,040
Total comprehensive income	$ 21,510	$ 16,540	$ 44,350	$ 25,880