Note 4 - Property - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Property, plant and equipment, gross	$ 58,959	$ 58,959
Less accumulated depreciation	33,631	33,215
Net property	25,328	25,744
Land [Member]
Property, plant and equipment, gross	5,059	5,059
Land Improvements [Member]
Property, plant and equipment, gross	18,051	18,051
Building [Member]
Property, plant and equipment, gross	24,884	24,884
Machinery and Equipment [Member]
Property, plant and equipment, gross	$ 10,965	$ 10,965