Consolidated Statement of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net Income (loss)	$ (100,870)	$ 19,110	$ (103,450)	$ 60,220
Other comprehensive income (loss)
Defined benefit plans	160	100	470	300
Foreign currency translation	5,740	(4,180)	(1,210)	(4,380)
Derivative instruments	(4,580)	4,260	(2,280)	5,750
Total other comprehensive income (loss)	1,320	180	(3,020)	1,670
Total comprehensive income (loss)	$ (99,550)	$ 19,290	$ (106,470)	$ 61,890