Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans (Details Textual) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)
Threshold for Designation to Impaired Status	$ 250
Interest and Fee Income, Loans and Leases, Total	$ 8,269	$ 7,532
Threshold Period for Considering Loans as Special Mention or Classified	75 days
Financing Receivable, Reclassification to Held-for-sale	$ 0
Financing Receivable, Troubled Debt Restructuring	$ 5,435	$ 10,648	$ 5,661
Financing Receivable, Modifications, Number of Contracts	0	2
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts		0
Real Estate Construction Portfolio Segment[Member]
Financing Receivable, Modifications, Number of Contracts		2
Consumer Real Estate Portfolio Segment [Member]
Financing Receivable, Troubled Debt Restructuring	$ 263
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts	7
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	$ 0
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts	1
Financing Receivables, Impaired, Troubled Debt Restructuring, Write-down	$ 0
Special Mention [Member]
Increase in Percentage of Allocation Loans Rated Special Mention	50.00%
Classified Excluding Impaired [Member]
Increase in Percentage of Allocation Loans Rated Classified	100.00%
Nonperforming Financial Instruments [Member]
Interest and Fee Income, Loans and Leases, Total	$ 0	$ 0	$ 0

Increase in the percentage of allocation for loans rated classified.

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Increase in the percentage of allocation for loans rated special mention.

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This is threshold for designation to impaired status for loan relationship that are non accrual, significantly past due, display credit weakness or are TDR.

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Represents the threshold period for considering loans as special mention or classified.

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Number of financing receivables that have been modified by troubled debt restructurings.

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Amount of financing receivable modified as troubled debt restructuring.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953676-111524

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-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=118939409&loc=d3e18845-111554

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Number of financing receivable contracts modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953682-111524

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Amount of financing receivable reclassified to held-for-sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 11
-Subparagraph (i)
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-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (f)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953423-111524

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Reflects the amount of the write-down related to a troubled debt restructuring.

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-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
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The aggregate interest and fee income generated by: (1) loans the Entity has positive intent and ability to hold for the foreseeable future, or until maturity or payoff, including commercial and consumer loans, whether domestic or foreign, which may consist of: (a) industrial and agricultural; (b) real estate; and (c) real estate construction loans; (d) trade financing; (e) lease financing; (f) home equity lines-of-credit; (g) automobile and other vehicle loans; and (h) credit card and other revolving-type loans and (2) loans and leases held-for-sale which may include mortgage loans, direct financing, and sales-type leases.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
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