Property, Plant And Equipment (Schedule Of Property, Plant And Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 659,825	$ 665,706
Less accumulated depreciation	(473,159)	(480,434)
Property, plant and equipment, Net	186,666	185,272
Land [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	5,867	5,689
Buildings And Building Improvements [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	76,139	85,672
Machinery And Equipment [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	506,652	521,382
Furniture And Fixtures [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	10,035	10,426
Vehicles [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	1,125	1,142
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	42,288	39,716
Construction In Progress[Member]
Property Plant And Equipment [Line Items]
Property, plant and equipment, gross	$ 17,719	$ 1,679