Consolidated Statement of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 98,620	$ 83,300	$ 30,960
Other comprehensive income
Defined benefit plans	(1,470)	3,250	1,670
Foreign currency translation	10,290	(6,880)	6,050
Derivative instruments	3,300	4,110	(650)
Total other comprehensive income (loss)	12,120	480	7,070
Total comprehensive income	$ 110,740	$ 83,780	$ 38,030