Note 4 - Loans and Allowance for Loan Losses - Past Due Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Loans past due	$ 18,125	$ 17,076
Loans, current	738,780	717,825
Loans	756,905	734,901
Residential Portfolio Segment [Member]
Loans past due	7,536	6,882
Loans, current	297,001	279,140
Loans	304,537	286,022
Commercial Real Estate Portfolio Segment [Member]
Loans	212,127	214,007
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Owner Occupied [Member]
Loans past due	2,616	1,825
Loans, current	73,213	75,780
Loans	75,829	77,605
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member]
Loans past due	2,796	2,785
Loans, current	90,287	87,747
Loans	93,083	90,532
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans past due	700	300
Loans, current	42,515	45,570
Loans	43,215	45,870
Commercial and Industrial Portfolio Segment [Member]
Loans past due	1,784	2,566
Loans, current	101,166	98,023
Loans	102,950	100,589
Consumer Portfolio Segment [Member]
Loans	137,291	134,283
Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due	1,215	1,438
Loans, current	63,325	58,334
Loans	64,540	59,772
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans past due	603	394
Loans, current	20,697	20,467
Loans	21,300	20,861
Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans past due	875	886
Loans, current	50,576	52,764
Loans	51,451	53,650
Financing Receivables, 30 to 59 Days Past Due [Member]
Loans past due	9,064	7,597
Financing Receivables, 30 to 59 Days Past Due [Member] | Residential Portfolio Segment [Member]
Loans past due	4,312	3,728
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Owner Occupied [Member]
Loans past due	1,870	134
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member]
Loans past due	83	261
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans past due	191	66
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans past due	1,075	1,283
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due	850	1,091
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans past due	136	349
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans past due	547	685
Financing Receivables, 60 to 89 Days Past Due [Member]
Loans past due	2,645	2,293
Financing Receivables, 60 to 89 Days Past Due [Member] | Residential Portfolio Segment [Member]
Loans past due	1,017	953
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Owner Occupied [Member]
Loans past due	512	366
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member]
Loans past due	235	18
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans past due	62	52
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans past due	234	483
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due	225	221
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans past due	232	45
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans past due	128	155
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans past due	6,416	7,186
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential Portfolio Segment [Member]
Loans past due	2,207	2,201
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Owner Occupied [Member]
Loans past due	234	1,325
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Nonowner Occupied [Member]
Loans past due	2,478	2,506
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Loans past due	447	182
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial and Industrial Portfolio Segment [Member]
Loans past due	475	800
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Automobile Loan [Member]
Loans past due	140	126
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Loans past due	235
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member] | Other Consumer Loans [Member]
Loans past due	$ 200	$ 46