Note 8 - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, beginning of period	$ 8,834	$ 7,841
Provision for (credit to) loan losses	225	188
Charge-offs	(82)	(26)
Recoveries	38	34
Allowance for loan losses, end of period	9,015	8,037
Commercial Portfolio Segment [Member] \| Commercial and Industrial [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, beginning of period	3,092	2,711
Provision for (credit to) loan losses	(16)	103
Charge-offs	0	0
Recoveries	7	15
Allowance for loan losses, end of period	3,083	2,829
Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, beginning of period	551	563
Provision for (credit to) loan losses	51	(6)
Charge-offs	0	0
Recoveries	0	0
Allowance for loan losses, end of period	602	557
Commercial Portfolio Segment [Member] \| Secured by Commercial Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, beginning of period	2,824	2,410
Provision for (credit to) loan losses	5	20
Charge-offs	0	0
Recoveries	0	1
Allowance for loan losses, end of period	2,829	2,431
Commercial Portfolio Segment [Member] \| Secured by Residential Real Estate [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, beginning of period	754	816
Provision for (credit to) loan losses	(1)	17
Charge-offs	(31)	0
Recoveries	21	2
Allowance for loan losses, end of period	743	835
State and Political Subdivisions Portfolio Segment [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, beginning of period	153	114
Provision for (credit to) loan losses	37	7
Charge-offs	0	0
Recoveries	0	0
Allowance for loan losses, end of period	190	121
Retail Portfolio Segment [Member] \| Consumer Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, beginning of period	164	57
Provision for (credit to) loan losses	28	18
Charge-offs	(35)	(26)
Recoveries	9	12
Allowance for loan losses, end of period	166	61
Retail Portfolio Segment [Member] \| Family Residential Mortgages [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, beginning of period	497	444
Provision for (credit to) loan losses	3	68
Charge-offs	0	0
Recoveries	0	0
Allowance for loan losses, end of period	500	512
Retail Portfolio Segment [Member] \| Home Equity Loans and Lines [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, beginning of period	338	357
Provision for (credit to) loan losses	18	20
Charge-offs	(16)	0
Recoveries	1	4
Allowance for loan losses, end of period	341	381
Unallocated Financing Receivables [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, beginning of period	461	369
Provision for (credit to) loan losses	100	(59)
Charge-offs	0	0
Recoveries	0	0
Allowance for loan losses, end of period	$ 561	$ 310

Provision for (credit to) loan and lease losses.

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- Definition

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

+ References

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- Definition

Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

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-SubTopic 210
-Section S99
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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 210
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-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

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-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707

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