Note 4 - Loans - Aging of Past Due Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Past due	$ 250	$ 3,068
Current	750,735	708,834
Loans	750,985	711,902
Greater than 90 days past due and still accruing	0	0
Financial Asset, 30 to 59 Days Past Due [Member]
Past due	2	0
Financial Asset, 60 to 89 Days Past Due [Member]
Past due	0	2,162
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	248	906
Commercial Real Estate Portfolio Segment [Member]
Loans	607,002	554,519
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Past due	0	0
Current	53,169	20,263
Loans	53,169	20,263
Greater than 90 days past due and still accruing	0	0
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Mortgage Loans [Member]
Past due	0	0
Current	475,146	460,701
Loans	475,146	460,701
Greater than 90 days past due and still accruing	0	0
Commercial Real Estate Portfolio Segment [Member] | Mortgage Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Mortgage Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Mortgage Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Land Loans [Member]
Past due	0	906
Current	8,367	10,045
Loans	8,367	10,951
Greater than 90 days past due and still accruing	0	0
Commercial Real Estate Portfolio Segment [Member] | Land Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Land Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Land Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	906
Commercial Real Estate Portfolio Segment [Member] | Farmland Loans [Member]
Past due	111	0
Current	70,209	62,604
Loans	70,320	62,604
Greater than 90 days past due and still accruing	0	0
Commercial Real Estate Portfolio Segment [Member] | Farmland Loans [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Farmland Loans [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Farmland Loans [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	111	0
Commercial Portfolio Segment [Member]
Past due	0	2,100
Current	77,704	80,152
Loans	77,704	82,252
Greater than 90 days past due and still accruing	0	0
Commercial Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	0	0
Commercial Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	0	2,100
Commercial Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	0
Consumer Portfolio Segment [Member]
Past due	2	0
Current	1,272	1,314
Loans	1,274	1,314
Greater than 90 days past due and still accruing	0	0
Consumer Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	2	0
Consumer Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	0	0
Consumer Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	0	0
Residential Portfolio Segment [Member]
Past due	137	62
Current	36,510	35,679
Loans	36,647	35,741
Greater than 90 days past due and still accruing	0	0
Residential Portfolio Segment [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	0	0
Residential Portfolio Segment [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	0	62
Residential Portfolio Segment [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	137	0
Agriculture [Member]
Past due	0	0
Current	28,358	38,076
Loans	28,358	38,076
Greater than 90 days past due and still accruing	0	0
Agriculture [Member] | Financial Asset, 30 to 59 Days Past Due [Member]
Past due	0	0
Agriculture [Member] | Financial Asset, 60 to 89 Days Past Due [Member]
Past due	0	0
Agriculture [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Past due	$ 0	$ 0