Note 6 - Discontinued Operations (Details Textual) - USD ($)		12 Months Ended
	Oct. 29, 2018	Dec. 31, 2018	Dec. 31, 2017
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax, Total		$ 129,000,000
Discontinued Operation, Provision for Loss (Gain) on Disposal, before Income Tax, Total		130,000,000
Dillco Fluid Service, Inc [Member]
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax, Total		129,000
Discontinued Operation, Provision for Loss (Gain) on Disposal, before Income Tax, Total		$ 130,000
Dillco Fluid Service, Inc [Member] | Discontinued Operations, Disposed of by Sale [Member]
Discontinued Operation, Gain (Loss) from Disposal of Discontinued Operation, before Income Tax, Total	$ 129,000
Discontinued Operation, Provision for Loss (Gain) on Disposal, before Income Tax, Total	$ 130,000