Note 5 - Loans and the Allowance for Loan Losses - Outstanding Loans (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loans	$ 619,718,000	$ 566,199,000
Deferred loan costs, net	3,561,000	3,257,000
Allowance for loan losses	(7,243,000)	(6,958,000)	$ (6,669,000)	$ (6,549,000)
Loans, net	616,036,000	562,498,000
Commercial Portfolio Segment [Member] \| Commercial Loans [Member]
Loans	47,892,000	49,563,000
Allowance for loan losses	(617,000)	(914,000)	(725,000)	(655,000)
Commercial Portfolio Segment [Member] \| Agricultural Loans [Member]
Loans	78,785,000	69,160,000
Allowance for loan losses	(653,000)	(538,000)	(623,000)	(466,000)
Commercial Portfolio Segment [Member] \| Real Estate Loan [Member]
Loans	316,986,000	271,710,000
Allowance for loan losses	(3,426,000)	(2,686,000)	(2,729,000)	(2,740,000)
Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Loans	31,181,000	40,161,000
Allowance for loan losses	(481,000)	(758,000)	(783,000)	(927,000)
Residential Portfolio Segment [Member] \| Real Estate Loan [Member]
Loans	14,530,000	15,900,000
Allowance for loan losses	(163,000)	(214,000)	(231,000)	(280,000)
Residential Portfolio Segment [Member] \| Equity Lines of Credit [Member]
Loans	35,471,000	38,490,000
Allowance for loan losses	(393,000)	(464,000)	(533,000)	(575,000)
Consumer Portfolio Segment [Member] \| Automobile Loan [Member]
Loans	90,310,000	77,135,000
Allowance for loan losses	(1,409,000)	(1,289,000)	(946,000)	(815,000)
Consumer Portfolio Segment [Member] \| Other Loans [Member]
Loans	4,563,000	4,080,000
Allowance for loan losses	$ (101,000)	$ (95,000)	$ (99,000)	$ (91,000)

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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