Note 4 - Loans - Age Analysis of Past Due Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Loans, past due	$ 1,281	$ 2,289
Loans, current	926,199	877,546
Gross loans	927,480	879,835
Recorded investment greater than 90 days and accruing
Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due	729	1,409
Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due	292	418
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	260	462
Commercial Portfolio Segment [Member]
Loans, past due
Loans, current	132,091	142,405
Gross loans	132,091	142,405
Recorded investment greater than 90 days and accruing
Commercial Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due
Commercial Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due
Commercial Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due
Commercial Real Estate Portfolio Segment [Member]
Gross loans	647,350	585,593
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans, past due
Loans, current	20,496	15,902
Gross loans	20,496	15,902
Recorded investment greater than 90 days and accruing
Commercial Real Estate Portfolio Segment [Member] | Commercial Non-owner Occupied [Member]
Loans, past due
Loans, current	431,246	377,668
Gross loans	431,246	377,668
Recorded investment greater than 90 days and accruing
Commercial Real Estate Portfolio Segment [Member] | Commercial Owner Occupied Loan [Member]
Loans, past due		142
Loans, current	195,608	191,881
Gross loans	195,608	192,023
Recorded investment greater than 90 days and accruing
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Construction Loans [Member]
Loans, past due
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Non-owner Occupied [Member]
Loans, past due
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Owner Occupied Loan [Member]
Loans, past due		142
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Construction Loans [Member]
Loans, past due
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Non-owner Occupied [Member]
Loans, past due
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Owner Occupied Loan [Member]
Loans, past due
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Construction Loans [Member]
Loans, past due
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Non-owner Occupied [Member]
Loans, past due
Commercial Real Estate Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Owner Occupied Loan [Member]
Loans, past due
Residential Portfolio Segment [Member]
Gross loans	100,539	101,912
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Individual Tax Identification Number Loan [Member]
Loans, past due	748	1,139
Loans, current	37,605	40,049
Gross loans	38,353	41,188
Recorded investment greater than 90 days and accruing
Residential Portfolio Segment [Member] | Real Estate Loan [Member] | Mortgage Receivable [Member]
Loans, past due	179	463
Loans, current	33,294	29,914
Gross loans	33,473	30,377
Recorded investment greater than 90 days and accruing
Residential Portfolio Segment [Member] | Home Equity Loan [Member]
Loans, past due	120	141
Loans, current	28,593	30,206
Gross loans	28,713	30,347
Recorded investment greater than 90 days and accruing
Residential Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Real Estate Loan [Member] | Individual Tax Identification Number Loan [Member]
Loans, past due	412	555
Residential Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Real Estate Loan [Member] | Mortgage Receivable [Member]
Loans, past due		290
Residential Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Home Equity Loan [Member]
Loans, past due	120	141
Residential Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Real Estate Loan [Member] | Individual Tax Identification Number Loan [Member]
Loans, past due	76	122
Residential Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Real Estate Loan [Member] | Mortgage Receivable [Member]
Loans, past due	179	173
Residential Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Home Equity Loan [Member]
Loans, past due
Residential Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real Estate Loan [Member] | Individual Tax Identification Number Loan [Member]
Loans, past due	260	462
Residential Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real Estate Loan [Member] | Mortgage Receivable [Member]
Loans, past due
Residential Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Home Equity Loan [Member]
Loans, past due
Consumer Portfolio Segment [Member]
Loans, past due	234	404
Loans, current	47,266	49,521
Gross loans	47,500	49,925
Recorded investment greater than 90 days and accruing
Consumer Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due	197	281
Consumer Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due	37	123
Consumer Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due