Note 9 - Allowance for Loan Losses and Credit Quality Information - Aging of Past Due Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Loans past due	$ 2,082	$ 2,990
Current loans	596,701	591,808
Loans receivable	598,783	594,798
Loans 90 days or more past due and still accruing	0	0
Residential Portfolio Segment [Member]
Loans past due	917	1,690
Current loans	106,286	105,315
Loans receivable	107,203	107,005
Loans 90 days or more past due and still accruing	0	0
Commercial Real Estate Portfolio Segment [Member]
Loans receivable	338,160	334,117
Commercial Real Estate Portfolio Segment [Member] \| Real Estate Loan [Member]
Loans past due	459	0
Current loans	188,292	175,177
Loans receivable	188,751	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	22	0
Current loans	149,387	158,940
Loans receivable	149,409	158,940
Loans 90 days or more past due and still accruing	0	0
Consumer Portfolio Segment [Member]
Loans past due	659	1,086
Current loans	71,631	72,681
Loans receivable	72,290	73,767
Loans 90 days or more past due and still accruing	0	0
Commercial Portfolio Segment [Member]
Loans past due	25	214
Current loans	81,105	79,695
Loans receivable	81,130	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	1,109	1,495
Financing Receivables, 30 to 59 Days Past Due [Member] \| Residential Portfolio Segment [Member]
Loans past due	380	727
Financing Receivables, 30 to 59 Days Past Due [Member] \| Commercial Real Estate Portfolio Segment [Member] \| Real Estate Loan [Member]
Loans past due	459	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	245	734
Financing Receivables, 30 to 59 Days Past Due [Member] \| Commercial Portfolio Segment [Member]
Loans past due	25	34
Financing Receivables, 60 to 89 Days Past Due [Member]
Loans past due	591	411
Financing Receivables, 60 to 89 Days Past Due [Member] \| Residential Portfolio Segment [Member]
Loans past due	455	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	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] \| Consumer Portfolio Segment [Member]
Loans past due	136	117
Financing Receivables, 60 to 89 Days Past Due [Member] \| Commercial Portfolio Segment [Member]
Loans past due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans past due	382	1,084
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Residential Portfolio Segment [Member]
Loans past due	82	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	0	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	22	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Consumer Portfolio Segment [Member]
Loans past due	278	235
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Commercial Portfolio Segment [Member]
Loans past due	$ 0	$ 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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