Note 8 - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, beginning of period	$ 10,464	$ 9,164	$ 9,887	$ 8,834
Provision for (credit to) loan losses	250	550	1,000	925
Charge-offs	(25)	(271)	(291)	(426)
Recoveries	76	51	169	161
Allowance for loan losses, end of period	10,765	9,494	10,765	9,494
Commercial Portfolio Segment [Member] \| Commercial and Industrial [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, beginning of period	4,270	3,302	4,689	3,092
Provision for (credit to) loan losses	540	844	176	1,036
Charge-offs	0	(207)	(72)	(207)
Recoveries	10	8	27	26
Allowance for loan losses, end of period	4,820	3,947	4,820	3,947
Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, beginning of period	287	675	590	551
Provision for (credit to) loan losses	14	(87)	(289)	37
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Allowance for loan losses, end of period	301	588	301	588
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	3,423	2,913	2,519	2,824
Provision for (credit to) loan losses	(154)	(60)	738	29
Charge-offs	0	0	0	0
Recoveries	0	8	12	8
Allowance for loan losses, end of period	3,269	2,861	3,269	2,861
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	721	722	629	754
Provision for (credit to) loan losses	79	(9)	147	(68)
Charge-offs	0	(15)	0	(51)
Recoveries	34	16	58	79
Allowance for loan losses, end of period	834	714	834	714
State and Political Subdivisions Portfolio Segment [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, beginning of period	120	201	115	153
Provision for (credit to) loan losses	1	45	6	93
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Allowance for loan losses, end of period	121	246	121	246
Retail Portfolio Segment [Member] \| Consumer Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, beginning of period	268	188	230	164
Provision for (credit to) loan losses	(7)	46	190	154
Charge-offs	(25)	(49)	(219)	(151)
Recoveries	31	16	66	34
Allowance for loan losses, end of period	267	201	267	201
Retail Portfolio Segment [Member] \| Family Residential Mortgages [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, beginning of period	586	433	549	497
Provision for (credit to) loan losses	(59)	(15)	(22)	(79)
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Allowance for loan losses, end of period	527	418	527	418
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	266	294	310	338
Provision for (credit to) loan losses	20	21	(29)	(17)
Charge-offs	0	0	0	(17)
Recoveries	1	3	6	14
Allowance for loan losses, end of period	287	318	287	318
Unallocated Financing Receivables [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses, beginning of period	523	436	256	461
Provision for (credit to) loan losses	(184)	(235)	83	(260)
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Allowance for loan losses, end of period	$ 339	$ 201	$ 339	$ 201

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.

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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.

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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.

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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
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
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-URI http://asc.fasb.org/extlink&oid=121614798&loc=d3e15032-111544

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
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-URI http://asc.fasb.org/extlink&oid=121611835&loc=SL6953423-111524

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 6.L.1)
-URI http://asc.fasb.org/extlink&oid=27010918&loc=d3e74567-122707

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