Property, Plant and Equipment, Net (Summary Of Property, Plant And Equipment) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 505,530	$ 541,916
Accumulated depreciation and depletion	(218,603)	(185,642)
Property, plant and equipment, net	286,927	356,274
Machinery And Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	368,220	360,353
Buildings, Improvements And Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	77,529	75,374
Automobiles, Trucks, Tractors and Trailers [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	6,550	6,450
Furniture And Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	19,707	19,668
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	5,078	6,700
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	28,446	28,671
Oil and Gas Producing Assets [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 0	$ 44,700