Inventories (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Inventory [Line Items]
Inventory, Raw Materials, Gross		$ 65,315	$ 66,391
Provision Bankruptcy Settlement		366	7,675	$ 7,175
Total restructuring charges, net	$ 16,910	5,186	5,848	2,559
Inventories		137,309	143,682
Energy Segment
Inventory [Line Items]
Total restructuring charges, net		$ (1,181)	$ 3,661	$ 54