Note 6 - Discontinued Operations (Details Textual) - USD ($)	1 Months Ended	9 Months Ended	12 Months Ended
	Dec. 31, 2018	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
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 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