Note 5 - Supplemental Balance Sheet Information - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment, Gross	$ 278,398	$ 272,335
Less – Accumulated depreciation	(185,498)	(177,449)
Property, plant & equipment, less accumulated depreciation	92,900	94,886
Land and Land Improvements [Member]
Property, Plant and Equipment, Gross	$ 7,851	6,703
Land and Land Improvements [Member] \| Minimum [Member]
Estimated Useful Lives (Year)	5 years
Land and Land Improvements [Member] \| Maximum [Member]
Estimated Useful Lives (Year)	40 years
Land, Buildings and Improvements [Member]
Property, Plant and Equipment, Gross	$ 48,190	49,084
Land, Buildings and Improvements [Member] \| Minimum [Member]
Estimated Useful Lives (Year)	4 years
Land, Buildings and Improvements [Member] \| Maximum [Member]
Estimated Useful Lives (Year)	10 years
Machinery and Equipment [Member]
Property, Plant and Equipment, Gross	$ 139,844	131,956
Machinery and Equipment [Member] \| Minimum [Member]
Estimated Useful Lives (Year)	3 years
Machinery and Equipment [Member] \| Maximum [Member]
Estimated Useful Lives (Year)	10 years
Furniture and Fixtures [Member]
Property, Plant and Equipment, Gross	$ 31,188	31,860
Furniture and Fixtures [Member] \| Minimum [Member]
Estimated Useful Lives (Year)	3 years
Furniture and Fixtures [Member] \| Maximum [Member]
Estimated Useful Lives (Year)	10 years
Vehicles [Member]
Property, Plant and Equipment, Gross	$ 45,768	45,496
Construction in Progress [Member]
Property, Plant and Equipment, Gross	$ 5,557	$ 7,236

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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