Note 4 - Loans - Segregated by Class of Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Loans	$ 779,991	$ 782,027	$ 768,497
Commercial and Agricultural Portfolio Segment [Member] | Commercial [Member]
Loans	51,368	57,410	46,693
Commercial and Agricultural Portfolio Segment [Member] | Agricultural [Member]
Loans	15,290	16,799	16,351
Real Estate Portfolio Segment [Member] | Commercial [Member]
Loans	373,263	373,534	354,098
Real Estate Portfolio Segment [Member] | Commercial Construction [Member]
Loans	44,305	47,849	49,659
Real Estate Portfolio Segment [Member] | Residential Construction [Member]
Loans	14,947	12,500	8,145
Real Estate Portfolio Segment [Member] | Residential [Member]
Loans	181,004	187,714	193,376
Real Estate Portfolio Segment [Member] | Farmland [Member]
Loans	64,056	62,709	67,111
Consumer and Other Portfolio Segment [Member] | Consumer [Member]
Loans	17,907	18,485	18,805
Consumer and Other Portfolio Segment [Member] | Other [Member]
Loans	$ 17,851	$ 5,027	$ 14,259