Note 4 - Property - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Property, plant and equipment, gross	$ 66,033	$ 65,962
Less accumulated depreciation	37,490	36,741
Net property	28,543	29,221
Land [Member]
Property, plant and equipment, gross	5,086	5,059
Land Improvements [Member]
Property, plant and equipment, gross	24,727	24,727
Building [Member]
Property, plant and equipment, gross	24,763	24,884
Machinery and Equipment [Member]
Property, plant and equipment, gross	11,295	11,143
Construction in Progress [Member]
Property, plant and equipment, gross	$ 162	$ 149

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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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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