Note 8 - Loans Receivable and Credit Disclosures - Activity in Allowance for Loan Losses (Details) - USD ($)	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Balance	$ 12,619,000	$ 11,684,000
Provision for loan losses	2,316,155	98,094
Recoveries of loans charged-off	7,000	41,000
Loans charged-off	(33,000)	(11,000)
Balance	14,909,000	11,812,000
Construction Real Estate [Member]
Balance	672,000	699,000
Provision for loan losses	80,000	26,000
Recoveries of loans charged-off	1,000	11,000
Loans charged-off	0	0
Balance	753,000	736,000
Family Residential Real Estate 1-4 [Member]
Balance	2,122,000	1,820,000
Provision for loan losses	214,000	28,000
Recoveries of loans charged-off		2,000
Loans charged-off
Balance	2,336,000	1,850,000
Commercial Real Estate Portfolio Segment [Member]
Balance	5,362,000	4,615,000
Provision for loan losses	1,220,000	155,000
Recoveries of loans charged-off	1,000
Loans charged-off	(31,000)
Balance	6,552,000	4,770,000
Agriculture Real Estate [Member]
Balance	1,326,000	1,198,000
Provision for loan losses	237,000	60,000
Recoveries of loans charged-off		0
Loans charged-off	0	0
Balance	1,563,000	1,258,000
Commercial Portfolio Segment [Member]
Balance	1,458,000	1,777,000
Provision for loan losses	212,000	(190,000)
Recoveries of loans charged-off	2,000	28,000
Loans charged-off		(5,000)
Balance	1,672,000	1,610,000
Agriculture [Member]
Balance	1,478,000	1,384,000
Provision for loan losses	337,000	8,000
Recoveries of loans charged-off
Loans charged-off
Balance	1,815,000	1,392,000
Consumer and Other [Member]
Balance	201,000	191,000
Provision for loan losses	16,000	11,000
Recoveries of loans charged-off	3,000
Loans charged-off	(2,000)	(6,000)
Balance	$ 218,000	$ 196,000

Amount of recovery of loans and lease receivables which had previously been fully or partially written-off as bad debts.

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Amount of loans and leases that have been written off from both loan receivables and allowance reserve for credit loss.

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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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Amount of expense related to estimated loss from loan and lease transactions.

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