Note 9 - Income Taxes (Details Textual) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Jun. 30, 2019
Elimination of AMT Operating Loss Carryforwards	$ 91.3
Income Tax Expense (Benefit), Total	$ (5.0)
Percentage of AMT Credit Carryforward to Be Received		50.00%
Amount of AMT Credit Carryforwards Expected to Be Received		$ 2.5

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=115929826&loc=d3e8736-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 20
-Section 45
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109238882&loc=d3e38679-109324

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration