Note 4 - Loans - Aging of Past Due Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Past due	$ 3,068	$ 1,314
Current	708,834	661,230
Loans	711,902	662,544
Greater than 90 days past due and still accruing	0	0
Financing Receivables, 30 to 59 Days Past Due [Member]
Past due	0	19
Financing Receivables, 60 to 89 Days Past Due [Member]
Past due	2,162	0
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	906	1,295
Commercial Real Estate Portfolio Segment [Member]
Loans	554,519	517,150
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Past due	0	0
Current	20,263	31,265
Loans	20,263	31,265
Greater than 90 days past due and still accruing	0	0
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Financing Receivables, Equal to 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	460,701	417,138
Loans	460,701	417,138
Greater than 90 days past due and still accruing	0	0
Commercial Real Estate Portfolio Segment [Member] | Mortgage Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Mortgage Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Mortgage Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Land Loans [Member]
Past due	906	993
Current	10,045	9,079
Loans	10,951	10,072
Greater than 90 days past due and still accruing	0	0
Commercial Real Estate Portfolio Segment [Member] | Land Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Land Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Land Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	906	993
Commercial Real Estate Portfolio Segment [Member] | Farmland Loans [Member]
Past due	0	0
Current	62,604	58,675
Loans	62,604	58,675
Greater than 90 days past due and still accruing	0	0
Commercial Real Estate Portfolio Segment [Member] | Farmland Loans [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Farmland Loans [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due	0	0
Commercial Real Estate Portfolio Segment [Member] | Farmland Loans [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	0	0
Commercial Portfolio Segment [Member]
Past due	2,100	321
Current	80,152	69,289
Loans	82,252	69,610
Greater than 90 days past due and still accruing	0	0
Commercial Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due	0	19
Commercial Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due	2,100	0
Commercial Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	0	302
Consumer Portfolio Segment [Member]
Past due	0	0
Current	1,314	689
Loans	1,314	689
Greater than 90 days past due and still accruing	0	0
Consumer Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due	0	0
Consumer Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due	0	0
Consumer Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	0	0
Residential Portfolio Segment [Member]
Past due	62	0
Current	35,679	37,161
Loans	35,741	37,161
Greater than 90 days past due and still accruing	0	0
Residential Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due	0	0
Residential Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due	62	0
Residential Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	0	0
Agriculture [Member]
Past due	0	0
Current	38,076	37,934
Loans	38,076	37,934
Greater than 90 days past due and still accruing	0	0
Agriculture [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due	0	0
Agriculture [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due	0	0
Agriculture [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	$ 0	$ 0