Note 4 - Loans and the Allowance for Loan Losses - Allocation of the Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Balance, beginning of year	$ 6,743	$ 6,198	$ 6,549	$ 6,078	$ 6,078
Losses charged to allowance	(120)	(310)	(175)	(530)	(979)
Recoveries	32	342	81	482	650
Provision	200	200	400	400	800
Balance, end of period	6,855	6,430	6,855	6,430	6,549
Loans, individually evaluated for impairment	5,300		5,300		5,442
Loans, collectively evaluated for impairment	470,791		470,791		455,681
Allowance for loan losses, individually evaluated for impairment	480		480		366
Allowance for loan losses, collectively evaluated for impairment	6,375		6,375		6,183
Loans	476,091		476,091		461,123
Commercial Portfolio Segment [Member] \| Commercial Loans [Member]
Balance, beginning of year	788	637	655	639	639
Losses charged to allowance	(67)		(67)	(73)
Recoveries	11	6	19	17
Provision	(27)	192	98	252
Balance, end of period	705	835	705	835	655
Loans, individually evaluated for impairment	105		105		16
Loans, collectively evaluated for impairment	39,289		39,289		41,277
Allowance for loan losses, individually evaluated for impairment	93		93		2
Allowance for loan losses, collectively evaluated for impairment	612		612		653
Loans	39,394		39,394		41,293
Commercial Portfolio Segment [Member] \| Agricultural Loans [Member]
Balance, beginning of year	473	311	466	294	294
Losses charged to allowance
Recoveries
Provision	41	105	48	122
Balance, end of period	514	416	514	416	466
Loans, individually evaluated for impairment	256		256		258
Loans, collectively evaluated for impairment	54,718		54,718		50,845
Allowance for loan losses, individually evaluated for impairment
Allowance for loan losses, collectively evaluated for impairment	514		514		466
Loans	54,974		54,974		51,103
Commercial Portfolio Segment [Member] \| Real Estate Loan [Member]
Balance, beginning of year	2,919	2,762	2,740	2,525	2,525
Losses charged to allowance		(252)		(252)
Recoveries	1	2	3	2
Provision	(108)	(47)	69	190
Balance, end of period	2,812	2,465	2,812	2,465	2,740
Loans, individually evaluated for impairment	2,258		2,258		2,323
Loans, collectively evaluated for impairment	234,533		234,533		223,813
Allowance for loan losses, individually evaluated for impairment	76		76		81
Allowance for loan losses, collectively evaluated for impairment	2,736		2,736		2,659
Loans	236,791		236,791		226,136
Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Balance, beginning of year	838	800	927	874	874
Losses charged to allowance
Recoveries		300		329
Provision	233	(217)	144	(320)
Balance, end of period	1,071	883	1,071	883	927
Loans, individually evaluated for impairment	823		823		833
Loans, collectively evaluated for impairment	23,996		23,996		21,071
Allowance for loan losses, individually evaluated for impairment	218		218		206
Allowance for loan losses, collectively evaluated for impairment	853		853		721
Loans	24,819		24,819		21,904
Residential Portfolio Segment [Member] \| Real Estate Loan [Member]
Balance, beginning of year	268	318	280	341	341
Losses charged to allowance
Recoveries	1	1	2	36
Provision	(17)	3	(30)	(55)
Balance, end of period	252	322	252	322	280
Loans, individually evaluated for impairment	1,288		1,288		1,615
Loans, collectively evaluated for impairment	17,664		17,664		19,668
Allowance for loan losses, individually evaluated for impairment	53		53		53
Allowance for loan losses, collectively evaluated for impairment	199		199		227
Loans	18,952		18,952		21,283
Residential Portfolio Segment [Member] \| Equity Lines of Credit [Member]
Balance, beginning of year	561	524	575	528	528
Losses charged to allowance		1		(23)
Recoveries	2	1	2	1
Provision	(2)	47	(16)	67
Balance, end of period	561	573	561	573	575
Loans, individually evaluated for impairment	260		260		326
Loans, collectively evaluated for impairment	41,951		41,951		42,012
Allowance for loan losses, individually evaluated for impairment	22		22		24
Allowance for loan losses, collectively evaluated for impairment	539		539		551
Loans	42,211		42,211		42,338
Consumer Portfolio Segment [Member] \| Automobile Loan [Member]
Balance, beginning of year	806	763	815	784	784
Losses charged to allowance	(40)	(53)	(90)	(158)
Recoveries	16	25	50	82
Provision	63	106	70	133
Balance, end of period	845	841	845	841	815
Loans, individually evaluated for impairment	308		308		69
Loans, collectively evaluated for impairment	54,947		54,947		53,484
Allowance for loan losses, individually evaluated for impairment	16		16
Allowance for loan losses, collectively evaluated for impairment	829		829		815
Loans	55,255		55,255		53,553
Consumer Portfolio Segment [Member] \| Other Loans [Member]
Balance, beginning of year	90	83	91	93	93
Losses charged to allowance	(13)	(6)	(18)	(24)
Recoveries	1	7	5	15
Provision	17	11	17	11
Balance, end of period	95	$ 95	95	$ 95	91
Loans, individually evaluated for impairment	2		2		2
Loans, collectively evaluated for impairment	3,693		3,693		3,511
Allowance for loan losses, individually evaluated for impairment	2		2
Allowance for loan losses, collectively evaluated for impairment	93		93		91
Loans	$ 3,695		$ 3,695		$ 3,513

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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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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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 to estimated loss from loan and lease transactions.

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