Note 13 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Deferred Tax Assets, Valuation Allowance	$ 0	$ 0
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability	401,000
Unrecognized Tax Benefits	$ 0	$ 0

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32537-109319

+ Details

Name:	us-gaap_DeferredTaxAssetsValuationAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of income tax expense (benefit) from continuing operations attributable to an adjustment of a deferred tax liability or asset for enacted changes in tax laws or rates or a change in the tax status of the entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of unrecognized tax benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 15A
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319

+ Details

Name:	us-gaap_UnrecognizedTaxBenefits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant