Note 4 - Loans - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Beginning balance	$ 8,166	$ 7,832
Charge-offs	(46)	(30)
Recoveries	10	14
Provision for loan losses	555	350
Ending balance	8,685	8,166
Individually evaluated for impairment			$ 680	$ 680
Collectively evaluated for impairment			8,005	7,486
	8,685	8,166	8,685	8,166
Individually evaluated for impairment			920	1,311
Collectively evaluated for impairment			710,982	661,233
			711,902	662,544
Commercial Real Estate Portfolio Segment [Member]
Beginning balance	6,331	6,185
Charge-offs	0
Recoveries	0
Provision for loan losses	249	146
Ending balance	6,580	6,331
Individually evaluated for impairment			680	680
Collectively evaluated for impairment			5,900	5,651
	6,331	6,331	6,580	6,331
Individually evaluated for impairment			906	993
Collectively evaluated for impairment			553,613	516,157
			554,519	517,150
Commercial Portfolio Segment [Member]
Beginning balance	813	697
Charge-offs	0
Recoveries	0
Provision for loan losses	252	116
Ending balance	1,065	813
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			1,065	813
	813	813	1,065	813
Individually evaluated for impairment			0	303
Collectively evaluated for impairment			82,252	69,307
			82,252	69,610
Consumer Portfolio Segment [Member]
Beginning balance	27	51
Charge-offs	(29)	(30)
Recoveries	8	13
Provision for loan losses	33	(7)
Ending balance	39	27
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			39	27
	27	27	39	27
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			1,314	689
			1,314	689
Residential Portfolio Segment [Member]
Beginning balance	300	325
Charge-offs	(17)
Recoveries	2	1
Provision for loan losses	19	(26)
Ending balance	304	300
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			304	300
	300	300	304	300
Individually evaluated for impairment			14	15
Collectively evaluated for impairment			35,727	37,146
			35,741	37,161
Agriculture [Member]
Beginning balance	693	504
Charge-offs	0
Recoveries	0
Provision for loan losses	0	189
Ending balance	693	693
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			693	693
	693	693	693	693
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			38,076	37,934
			38,076	37,934
Unallocated Financing Receivables [Member]
Beginning balance	2	70
Charge-offs	0
Recoveries	0
Provision for loan losses	2	(68)
Ending balance	4	2
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			4	2
	$ 2	$ 2	4	2
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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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 direct write-downs of financing receivables charged against the allowance.

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The balance of financing receivables that were collectively evaluated for impairment.

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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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