Note 9 - Allowance for Loan Losses and Credit Quality Information - Aging of Past Due Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Loans past due	$ 4,417	$ 2,990
Current loans	589,982	591,808
Loans receivable	594,399	594,798
Loans 90 days or more past due and still accruing	0	0
Residential Portfolio Segment [Member]
Loans past due	1,119	1,690
Current loans	107,374	105,315
Loans receivable	108,493	107,005
Loans 90 days or more past due and still accruing	0	0
Commercial Real Estate Portfolio Segment [Member]
Loans receivable	332,503	334,117
Commercial Real Estate Portfolio Segment [Member] \| Real Estate Loan [Member]
Loans past due	210	0
Current loans	187,163	175,177
Loans receivable	187,373	175,177
Loans 90 days or more past due and still accruing	0	0
Commercial Real Estate Portfolio Segment [Member] \| Commercial Real Estate Other [Member]
Loans past due	2,227	0
Current loans	142,903	158,940
Loans receivable	145,130	158,940
Loans 90 days or more past due and still accruing	0	0
Consumer Portfolio Segment [Member]
Loans past due	774	1,086
Current loans	73,747	72,681
Loans receivable	74,521	73,767
Loans 90 days or more past due and still accruing	0	0
Commercial Portfolio Segment [Member]
Loans past due	87	214
Current loans	78,795	79,695
Loans receivable	78,882	79,909
Loans 90 days or more past due and still accruing		0
Financing Receivables, 30 to 59 Days Past Due [Member]
Loans past due	1,251	1,495
Financing Receivables, 30 to 59 Days Past Due [Member] \| Residential Portfolio Segment [Member]
Loans past due	897	727
Financing Receivables, 30 to 59 Days Past Due [Member] \| Commercial Real Estate Portfolio Segment [Member] \| Real Estate Loan [Member]
Loans past due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] \| Commercial Real Estate Portfolio Segment [Member] \| Commercial Real Estate Other [Member]
Loans past due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] \| Consumer Portfolio Segment [Member]
Loans past due	324	734
Financing Receivables, 30 to 59 Days Past Due [Member] \| Commercial Portfolio Segment [Member]
Loans past due	30	34
Financing Receivables, 60 to 89 Days Past Due [Member]
Loans past due	2,366	411
Financing Receivables, 60 to 89 Days Past Due [Member] \| Residential Portfolio Segment [Member]
Loans past due	0	294
Financing Receivables, 60 to 89 Days Past Due [Member] \| Commercial Real Estate Portfolio Segment [Member] \| Real Estate Loan [Member]
Loans past due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] \| Commercial Real Estate Portfolio Segment [Member] \| Commercial Real Estate Other [Member]
Loans past due	2,227	0
Financing Receivables, 60 to 89 Days Past Due [Member] \| Consumer Portfolio Segment [Member]
Loans past due	115	117
Financing Receivables, 60 to 89 Days Past Due [Member] \| Commercial Portfolio Segment [Member]
Loans past due	24	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans past due	800	1,084
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Residential Portfolio Segment [Member]
Loans past due	222	669
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Commercial Real Estate Portfolio Segment [Member] \| Real Estate Loan [Member]
Loans past due	210	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Commercial Real Estate Portfolio Segment [Member] \| Commercial Real Estate Other [Member]
Loans past due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Consumer Portfolio Segment [Member]
Loans past due	335	235
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Commercial Portfolio Segment [Member]
Loans past due	$ 33	$ 180

Recorded investment in financing receivables that are 90 days or more past due and still accruing.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5111-111524

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Financing receivables that are current.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-SubTopic 10
-Section 45
-Paragraph 2
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