Property, Plant And Equipment (Schedule Of Property, Plant And Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	$ 734,041	$ 697,027
Less: Accumulated depreciation	(506,343)	(485,549)
Total property, plant and equipment, net	227,698	211,478
Land [Member]
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	5,867	5,867
Buildings And Building Improvements [Member]
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	81,282	79,178
Machinery And Equipment [Member]
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	553,468	542,034
Furniture And Fixtures [Member]
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	12,897	11,430
Vehicles [Member]
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	1,115	1,099
Leasehold Improvements [Member]
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	54,754	54,272
Construction In Progress[Member]
Property Plant And Equipment [Line Items]
Total property and equipment, at cost	$ 24,658	$ 3,147