Note 3 - Loans - Segregated by Class of Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Loans	$ 766,796	$ 765,284	$ 775,566
Commercial and Agricultural Portfolio Segment [Member] | Commercial [Member]
Loans	45,029	48,122	44,883
Commercial and Agricultural Portfolio Segment [Member] | Agricultural [Member]
Loans	20,037	16,443	21,810
Real Estate Portfolio Segment [Member] | Commercial [Member]
Loans	352,063	351,172	355,801
Real Estate Portfolio Segment [Member] | Commercial Construction [Member]
Loans	48,909	45,214	35,151
Real Estate Portfolio Segment [Member] | Residential Construction [Member]
Loans	11,541	8,583	9,230
Real Estate Portfolio Segment [Member] | Residential [Member]
Loans	187,591	194,049	200,572
Real Estate Portfolio Segment [Member] | Farmland [Member]
Loans	67,867	67,768	70,194
Consumer and Other Portfolio Segment [Member] | Consumer [Member]
Loans	18,746	18,956	19,134
Consumer and Other Portfolio Segment [Member] | Other [Member]
Loans	$ 15,013	$ 14,977	$ 18,791