Note 4 - Allowance for Loan Losses - Segregated by Impairment Methodology (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Ending allowance balance, individually evaluated for impairment	$ 1,585		$ 2,960
Ending allowance balance, collectively evaluated for impairment	6,392		6,243
Ending allowance balance	7,977	$ 8,923	9,203	$ 8,604
Ending loan balance, individually evaluated for impairment	21,426		28,998
Ending loan balance, collectively evaluated for impairment	748,620		747,119
Ending loan balance	770,046	754,283	776,117
Commercial [Member] \| Commercial and Agricultural Portfolio Segment [Member]
Ending allowance balance, individually evaluated for impairment
Ending allowance balance, collectively evaluated for impairment	436		491
Ending allowance balance	436	456	491	855
Ending loan balance, individually evaluated for impairment	77		8
Ending loan balance, collectively evaluated for impairment	45,286		45,765
Ending loan balance	45,363	47,025	45,773
Commercial [Member] \| Real Estate Portfolio Segment [Member]
Ending allowance balance, individually evaluated for impairment	1,471		2,470
Ending allowance balance, collectively evaluated for impairment	2,752		2,817
Ending allowance balance	4,223	5,751	5,287	3,851
Ending loan balance, individually evaluated for impairment	17,605		24,363
Ending loan balance, collectively evaluated for impairment	328,646		325,029
Ending loan balance	346,251	349,090	349,392
Agricultural [Member] \| Commercial and Agricultural Portfolio Segment [Member]
Ending allowance balance, individually evaluated for impairment
Ending allowance balance, collectively evaluated for impairment	249		281
Ending allowance balance	249	168	281	203
Ending loan balance, individually evaluated for impairment	5
Ending loan balance, collectively evaluated for impairment	25,241		26,547
Ending loan balance	25,246	17,080	26,547
Commercial Construction [Member] \| Real Estate Portfolio Segment [Member]
Ending allowance balance, individually evaluated for impairment	69		22
Ending allowance balance, collectively evaluated for impairment	919		436
Ending allowance balance	988	323	458	691
Ending loan balance, individually evaluated for impairment	497		380
Ending loan balance, collectively evaluated for impairment	36,036		33,344
Ending loan balance	36,533	30,358	33,724
Residential Construction [Member] \| Real Estate Portfolio Segment [Member]
Ending allowance balance, individually evaluated for impairment
Ending allowance balance, collectively evaluated for impairment	6		22
Ending allowance balance	6	13	22	20
Ending loan balance, individually evaluated for impairment
Ending loan balance, collectively evaluated for impairment	8,905		10,325
Ending loan balance	8,905	11,830	10,325
Residential [Member] \| Real Estate Portfolio Segment [Member]
Ending allowance balance, individually evaluated for impairment	21		435
Ending allowance balance, collectively evaluated for impairment	1,108		1,230
Ending allowance balance	1,129	1,396	1,665	1,990
Ending loan balance, individually evaluated for impairment	2,204		3,200
Ending loan balance, collectively evaluated for impairment	194,128		191,845
Ending loan balance	196,332	195,580	195,045
Farmland [Member] \| Real Estate Portfolio Segment [Member]
Ending allowance balance, individually evaluated for impairment	24		33
Ending allowance balance, collectively evaluated for impairment	848		829
Ending allowance balance	872	722	862	912
Ending loan balance, individually evaluated for impairment	1,038		1,047
Ending loan balance, collectively evaluated for impairment	70,865		72,754
Ending loan balance	71,903	66,877	73,801
Consumer [Member] \| Consumer and Other Portfolio Segment [Member]
Ending allowance balance, individually evaluated for impairment
Ending allowance balance, collectively evaluated for impairment	56		103
Ending allowance balance	56	80	103	63
Ending loan balance, individually evaluated for impairment
Ending loan balance, collectively evaluated for impairment	18,677		20,378
Ending loan balance	18,677	19,695	20,378
Other [Member] \| Consumer and Other Portfolio Segment [Member]
Ending allowance balance, individually evaluated for impairment
Ending allowance balance, collectively evaluated for impairment	18		34
Ending allowance balance	18	14	34	$ 19
Ending loan balance, individually evaluated for impairment
Ending loan balance, collectively evaluated for impairment	20,836		21,132
Ending loan balance	$ 20,836	$ 16,748	$ 21,132

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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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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