Note 5 - Leasing Arrangements (Details Textual) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment, Net, Ending Balance	$ 19,719	$ 21,525
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Ending Balance	32,445	33,150
Assets Leased to Others [Member]
Property, Plant and Equipment, Net, Ending Balance	42,500	42,500
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Ending Balance	$ 28,400	$ 27,200