Note 3 - Loans Receivable - Past Due and Non-accrual Status of Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Loans, past due	$ 2,001	$ 1,926
Loans, current	426,042	417,065
Loans	428,043	418,991
Loans, nonaccrual loans	936	924
Construction Loan Portfolio Segment [Member] | Residential [Member]
Loans, past due
Loans, current	10,429	10,204
Loans	10,429	10,204
Loans, nonaccrual loans
Construction Loan Portfolio Segment [Member] | Land Acquisition Development And Commercial [Member]
Loans, past due
Loans, current	29,662	27,480
Loans	29,662	27,480
Loans, nonaccrual loans
Real Estate Portfolio Segment [Member] | Residential [Member]
Loans, past due	1,362	1,442
Loans, current	110,626	110,184
Loans	111,988	111,626
Loans, nonaccrual loans	577	577
Real Estate Portfolio Segment [Member] | Commercial [Member]
Loans, past due	21	115
Loans, current	175,633	172,133
Loans	175,654	172,248
Loans, nonaccrual loans	330	336
Commercial Industrial and Agricultural Portfolio Segment [Member]
Loans, past due	499	93
Loans, current	61,145	59,716
Loans	61,644	59,809
Loans, nonaccrual loans	29	11
Equity Lines Portfolio Segment [Member]
Loans, past due	105	258
Loans, current	30,718	29,698
Loans	30,823	29,956
Loans, nonaccrual loans
Consumer Portfolio Segment [Member]
Loans, past due	14	18
Loans, current	7,829	7,650
Loans	7,843	7,668
Loans, nonaccrual loans
Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due	1,209	1,113
Financing Receivables, 30 to 59 Days Past Due [Member] | Construction Loan Portfolio Segment [Member] | Residential [Member]
Loans, past due
Financing Receivables, 30 to 59 Days Past Due [Member] | Construction Loan Portfolio Segment [Member] | Land Acquisition Development And Commercial [Member]
Loans, past due
Financing Receivables, 30 to 59 Days Past Due [Member] | Real Estate Portfolio Segment [Member] | Residential [Member]
Loans, past due	785	672
Financing Receivables, 30 to 59 Days Past Due [Member] | Real Estate Portfolio Segment [Member] | Commercial [Member]
Loans, past due	21	115
Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Industrial and Agricultural Portfolio Segment [Member]
Loans, past due	292	60
Financing Receivables, 30 to 59 Days Past Due [Member] | Equity Lines Portfolio Segment [Member]
Loans, past due	105	258
Financing Receivables, 30 to 59 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Loans, past due	6	8
Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due		232
Financing Receivables, 60 to 89 Days Past Due [Member] | Construction Loan Portfolio Segment [Member] | Residential [Member]
Loans, past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Construction Loan Portfolio Segment [Member] | Land Acquisition Development And Commercial [Member]
Loans, past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Real Estate Portfolio Segment [Member] | Residential [Member]
Loans, past due		193
Financing Receivables, 60 to 89 Days Past Due [Member] | Real Estate Portfolio Segment [Member] | Commercial [Member]
Loans, past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Industrial and Agricultural Portfolio Segment [Member]
Loans, past due		33
Financing Receivables, 60 to 89 Days Past Due [Member] | Equity Lines Portfolio Segment [Member]
Loans, past due
Financing Receivables, 60 to 89 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Loans, past due		6
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	792	581
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Construction Loan Portfolio Segment [Member] | Residential [Member]
Loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Construction Loan Portfolio Segment [Member] | Land Acquisition Development And Commercial [Member]
Loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real Estate Portfolio Segment [Member] | Residential [Member]
Loans, past due	577	577
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real Estate Portfolio Segment [Member] | Commercial [Member]
Loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Industrial and Agricultural Portfolio Segment [Member]
Loans, past due	207
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Equity Lines Portfolio Segment [Member]
Loans, past due
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Loans, past due	$ 8	$ 4