Consolidated Statement of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net Income	$ 19,090	$ 24,320
Other comprehensive income
Defined benefit plans	100	200
Foreign currency translation	700	2,360
Derivative instruments	2,220	(4,040)
Total other comprehensive income (loss)	3,020	(1,480)
Total comprehensive income	$ 22,110	$ 22,840