Note 4 - Loans and the Allowance for Loan Losses - Outstanding Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Loans	$ 623,743	$ 619,718
Deferred loan costs, net	3,548	3,561
Allowance for loan losses	(7,804)	(7,243)	$ (7,067)	$ (6,958)
Total net loans	619,487	616,036
Commercial Portfolio Segment [Member] \| Commercial Loans [Member]
Loans	49,246	47,892
Allowance for loan losses	(714)	(617)	(796)	(914)
Commercial Portfolio Segment [Member] \| Agricultural Loans [Member]
Loans	76,044	78,785
Allowance for loan losses	(622)	(653)	(542)	(538)
Commercial Portfolio Segment [Member] \| Real Estate Loan [Member]
Loans	332,294	316,986
Allowance for loan losses	(3,830)	(3,426)	(2,969)	(2,686)
Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Loans	19,674	31,181
Allowance for loan losses	(397)	(481)	(641)	(758)
Residential Portfolio Segment [Member] \| Real Estate Loan [Member]
Loans	13,820	14,530
Allowance for loan losses	(171)	(163)	(195)	(214)
Residential Portfolio Segment [Member] \| Equity Lines of Credit [Member]
Loans	35,262	35,471
Allowance for loan losses	(422)	(393)	(450)	(464)
Consumer Portfolio Segment [Member] \| Automobile Loan [Member]
Loans	92,862	90,310
Allowance for loan losses	(1,541)	(1,409)	(1,384)	(1,289)
Consumer Portfolio Segment [Member] \| Other Loans [Member]
Loans	4,541	4,563
Allowance for loan losses	$ (107)	$ (101)	$ (90)	$ (95)

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

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