Note H - Property, Plant and Equipment - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property, plant and equipment, gross	$ 363,363	$ 356,168
Less accumulated depreciation and amortization	(194,086)	(177,519)
Property, plant and equipment, net before construction in progress and land	169,277	178,649
Property, plant and equipment, net	200,317	210,184
Land Improvements [Member]
Property, plant and equipment, gross	806	806
Building and Building Improvements [Member]
Property, plant and equipment, gross	86,534	86,372
Machinery and Equipment [Member]
Property, plant and equipment, gross	257,842	251,216
Furniture and Fixtures [Member]
Property, plant and equipment, gross	5,449	5,382
Computer Equipment and Software [Member]
Property, plant and equipment, gross	12,059	11,713
Vehicles [Member]
Property, plant and equipment, gross	673	679
Construction in Progress [Member]
Property, plant and equipment, net	29,939	30,434
Land [Member]
Property, plant and equipment, net	$ 1,101	$ 1,101