Note 6 - Allowance for Loan Losses and Credit Quality Information - Aging of Past Due Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Loans past due	$ 1,707	$ 2,464
Current Loans	559,087	470,355
Loans receivable	560,794	472,819
Loans 90 days or more past due and still accruing	0	0
Residential Portfolio Segment [Member]
Loans past due	679	1,419
Current Loans	102,576	89,526
Loans receivable	103,255	90,945
Loans 90 days or more past due and still accruing	0	0
Commercial Real Estate Portfolio Segment [Member]
Loans receivable	299,080	247,353
Commercial Real Estate Portfolio Segment [Member] \| Real Estate Loan [Member]
Loans past due	0	0
Current Loans	153,343	125,376
Loans receivable	153,343	125,376
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	0	289
Current Loans	145,737	121,688
Loans receivable	145,737	121,977
Loans 90 days or more past due and still accruing	0	0
Consumer Portfolio Segment [Member]
Loans past due	669	711
Current Loans	72,614	63,704
Loans receivable	73,283	64,415
Loans 90 days or more past due and still accruing	0	0
Commercial Portfolio Segment [Member]
Loans receivable	85,176	70,106
Commercial Portfolio Segment [Member] \| Transportation Industry Loans [Member]
Loans past due	0	0
Current Loans	10,509	9,349
Loans receivable	10,509	9,349
Loans 90 days or more past due and still accruing	0	0
Commercial Portfolio Segment [Member] \| Commercial Business Other [Member]
Loans past due	359	45
Current Loans	74,308	60,712
Loans receivable	74,667	60,757
Loans 90 days or more past due and still accruing	0	0
Financing Receivables, 30 to 59 Days Past Due [Member]
Loans past due	839	865
Financing Receivables, 30 to 59 Days Past Due [Member] \| Residential Portfolio Segment [Member]
Loans past due	342	490
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	412	330
Financing Receivables, 30 to 59 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Transportation Industry Loans [Member]
Loans past due	0	0
Financing Receivables, 30 to 59 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Commercial Business Other [Member]
Loans past due	85	45
Financing Receivables, 60 to 89 Days Past Due [Member]
Loans past due	275	681
Financing Receivables, 60 to 89 Days Past Due [Member] \| Residential Portfolio Segment [Member]
Loans past due	158	130
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	289
Financing Receivables, 60 to 89 Days Past Due [Member] \| Consumer Portfolio Segment [Member]
Loans past due	117	262
Financing Receivables, 60 to 89 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Transportation Industry Loans [Member]
Loans past due	0	0
Financing Receivables, 60 to 89 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Commercial Business Other [Member]
Loans past due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans past due	593	918
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Residential Portfolio Segment [Member]
Loans past due	179	799
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	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Consumer Portfolio Segment [Member]
Loans past due	140	119
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Transportation Industry Loans [Member]
Loans past due	0	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] \| Commercial Portfolio Segment [Member] \| Commercial Business Other [Member]
Loans past due	$ 274	$ 0

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Recorded Investment
-URI http://asc.fasb.org/extlink&oid=65880944

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5111-111524

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- Definition

Financing receivables that are current.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953401-111524

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Recorded Investment in financing receivables that are past due at the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Recorded Investment
-URI http://asc.fasb.org/extlink&oid=65880944

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953401-111524

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Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65884687&loc=d3e4428-111522

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