Note 3 - Loans (Details) - Age Analysis of Past Due Loans and Nonaccrual Loans - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Commercial and Agricultural
Accruing loans past due	$ 6,488	$ 9,708
Nonaccrual loans	13,559	18,334
Current loans	744,157	718,052
Loans receivable	764,204	746,094	$ 743,281
Financing Receivables, 30-89 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	6,480	9,701
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	8	7
Commercial and Agricultural Portfolio Segment [Member] | Commercial [Member]
Commercial and Agricultural
Accruing loans past due	659	872
Nonaccrual loans	664	405
Current loans	47,436	49,683
Loans receivable	48,759	50,960	46,481
Commercial and Agricultural Portfolio Segment [Member] | Commercial [Member] | Financing Receivables, 30-89 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	659	872
Commercial and Agricultural Portfolio Segment [Member] | Commercial [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	0	0
Commercial and Agricultural Portfolio Segment [Member] | Agricultural [Member]
Commercial and Agricultural
Accruing loans past due	22	0
Nonaccrual loans	156	45
Current loans	27,195	16,644
Loans receivable	27,373	16,689	23,017
Commercial and Agricultural Portfolio Segment [Member] | Agricultural [Member] | Financing Receivables, 30-89 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	22	0
Commercial and Agricultural Portfolio Segment [Member] | Agricultural [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	0	0
Real Estate Portfolio Segment [Member] | Commercial [Member]
Commercial and Agricultural
Accruing loans past due	2,689	2,309
Nonaccrual loans	5,242	5,325
Current loans	339,772	324,597
Loans receivable	347,703	332,231	327,498
Real Estate Portfolio Segment [Member] | Commercial [Member] | Financing Receivables, 30-89 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	2,689	2,309
Real Estate Portfolio Segment [Member] | Commercial [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	0	0
Real Estate Portfolio Segment [Member] | Commercial Constuction [Member]
Commercial and Agricultural
Accruing loans past due	478	142
Nonaccrual loans	2,479	3,251
Current loans	40,632	47,866
Loans receivable	43,589	51,259	50,455
Real Estate Portfolio Segment [Member] | Commercial Constuction [Member] | Financing Receivables, 30-89 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	478	142
Real Estate Portfolio Segment [Member] | Commercial Constuction [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	0	0
Real Estate Portfolio Segment [Member] | Residential Construction [Member]
Commercial and Agricultural
Accruing loans past due	0	0
Nonaccrual loans	0	0
Current loans	10,465	11,221
Loans receivable	10,465	11,221	9,700
Real Estate Portfolio Segment [Member] | Residential Construction [Member] | Financing Receivables, 30-89 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	0	0
Real Estate Portfolio Segment [Member] | Residential Construction [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	0	0
Real Estate Portfolio Segment [Member] | Residential [Member]
Commercial and Agricultural
Accruing loans past due	2,299	5,783
Nonaccrual loans	3,434	7,462
Current loans	190,067	190,508
Loans receivable	195,800	203,753	204,313
Real Estate Portfolio Segment [Member] | Residential [Member] | Financing Receivables, 30-89 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	2,299	5,783
Real Estate Portfolio Segment [Member] | Residential [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	0	0
Real Estate Portfolio Segment [Member] | Farmland [Member]
Commercial and Agricultural
Accruing loans past due	72	282
Nonaccrual loans	1,397	1,449
Current loans	60,082	48,220
Loans receivable	61,551	49,951	50,401
Real Estate Portfolio Segment [Member] | Farmland [Member] | Financing Receivables, 30-89 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	72	282
Real Estate Portfolio Segment [Member] | Farmland [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	0	0
Consumer and Other Portfolio Segment [Member] | Consumer [Member]
Commercial and Agricultural
Accruing loans past due	243	320
Nonaccrual loans	187	202
Current loans	20,528	22,298
Loans receivable	20,958	22,820	23,448
Consumer and Other Portfolio Segment [Member] | Consumer [Member] | Financing Receivables, 30-89 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	235	313
Consumer and Other Portfolio Segment [Member] | Consumer [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	8	7
Consumer and Other Portfolio Segment [Member] | Other [Member]
Commercial and Agricultural
Accruing loans past due	26	0
Nonaccrual loans	0	195
Current loans	7,980	7,015
Loans receivable	8,006	7,210	$ 7,968
Consumer and Other Portfolio Segment [Member] | Other [Member] | Financing Receivables, 30-89 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	26	0
Consumer and Other Portfolio Segment [Member] | Other [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Commercial and Agricultural
Accruing loans past due	$ 0	$ 0