Note 3 - Loans - Segregated by Class of Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016
Loans	$ 770,046	$ 754,283	$ 776,117
Commercial and Agricultural Portfolio Segment [Member] | Commercial [Member]
Loans	45,363	47,025	45,773
Commercial and Agricultural Portfolio Segment [Member] | Agricultural [Member]
Loans	25,246	17,080	26,547
Real Estate Portfolio Segment [Member] | Commercial [Member]
Loans	346,251	349,090	349,392
Real Estate Portfolio Segment [Member] | Commercial Construction [Member]
Loans	36,533	30,358	33,724
Real Estate Portfolio Segment [Member] | Residential Construction [Member]
Loans	8,905	11,830	10,325
Real Estate Portfolio Segment [Member] | Residential [Member]
Loans	196,332	195,580	195,045
Real Estate Portfolio Segment [Member] | Farmland [Member]
Loans	71,903	66,877	73,801
Consumer and Other Portfolio Segment [Member] | Consumer [Member]
Loans	18,677	19,695	20,378
Consumer and Other Portfolio Segment [Member] | Other [Member]
Loans	$ 20,836	$ 16,748	$ 21,132