Note 6 - Discontinued Operations (Details Textual) - Dillco Fluid Service, Inc [Member] - Discontinued Operations, Disposed of by Sale [Member] - USD ($)	1 Months Ended	12 Months Ended
Dec. 31, 2018	Dec. 31, 2019
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

Amount before tax of (gain) loss recognized for the (reversal of write-down) write-down to fair value, less cost to sell, of a discontinued operation.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 3B
-URI http://asc.fasb.org/extlink&oid=109222160&loc=SL51721525-107759

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
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-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109222650&loc=d3e1361-107760

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109222160&loc=d3e957-107759

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