Note 4 - Loans - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Beginning balance	$ 8,685	$ 8,166
Charge-offs	(92)	(46)
Recoveries	8	10
Provision for loan losses	545	555
Ending balance	9,146	8,685
Individually evaluated for impairment			$ 680	$ 680
Collectively evaluated for impairment			8,466	8,005
	8,685	8,166	9,146	8,685
Individually evaluated for impairment			1,103	920
Collectively evaluated for impairment			749,882	710,982
			750,985	711,902
Commercial Real Estate Portfolio Segment [Member]
Beginning balance	6,580	6,331
Charge-offs	0	0
Recoveries	0	0
Provision for loan losses	590	249
Ending balance	7,170	6,580
Individually evaluated for impairment			680	680
Collectively evaluated for impairment			6,490	5,900
	7,170	6,331	7,170	6,580
Individually evaluated for impairment			855	906
Collectively evaluated for impairment			606,147	553,613
			607,002	554,519
Commercial Portfolio Segment [Member]
Beginning balance	1,065	813
Charge-offs	0	0
Recoveries	0	0
Provision for loan losses	(65)	252
Ending balance	1,000	1,065
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			1,000	1,065
	1,000	813	1,000	1,065
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			77,704	82,252
			77,704	82,252
Consumer Portfolio Segment [Member]
Beginning balance	39	27
Charge-offs	(28)	(29)
Recoveries	6	8
Provision for loan losses	21	33
Ending balance	38	39
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			38	39
	38	27	38	39
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			1,274	1,314
			1,274	1,314
Residential Portfolio Segment [Member]
Beginning balance	304	300
Charge-offs	(64)	(17)
Recoveries	2	2
Provision for loan losses	64	19
Ending balance	306	304
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			306	304
	306	300	306	304
Individually evaluated for impairment			248	14
Collectively evaluated for impairment			36,399	35,727
			36,647	35,741
Agriculture [Member]
Beginning balance	693	693
Charge-offs	0	0
Recoveries	0	0
Provision for loan losses	(168)	0
Ending balance	525	693
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			525	693
	525	693	525	693
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			28,358	38,076
			28,358	38,076
Unallocated Financing Receivables [Member]
Beginning balance	4	2
Charge-offs	0	0
Recoveries	0	0
Provision for loan losses	103	2
Ending balance	107	4
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			107	4
	$ 107	$ 2	107	4
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			0	0
			$ 0	$ 0

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

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The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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Amount of writeoff of financing receivable, charged against allowance 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 before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

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