Note 4 - Credit Quality - Average Annual Recorded Investment and Interest Income Recognized on Impaired Loans Excluding Purchased Credit Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Impaired loans with no related allowance, interest income recognized	$ 138	$ 161	$ 351	$ 315
Impaired loans with no related allowance, average recorded investment	25,805	25,929	28,395	23,669
Impaired loans with a related allowance, interest income recognized	61	81	100	149
Impaired loans with a related allowance, average recorded investment	8,891	7,367	7,943	8,198
Total impaired loans, interest income recognized	199	242	451	464
Total impaired loans, average recorded investment	34,696	33,296	36,338	31,867
Commercial Portfolio Segment [Member] \| Construction, Development and Other Land [Member]
Impaired loans with no related allowance, interest income recognized	1		14
Impaired loans with no related allowance, average recorded investment	823	10	969	11
Impaired loans with a related allowance, interest income recognized
Impaired loans with a related allowance, average recorded investment				214
Commercial Portfolio Segment [Member] \| Commercial and Industrial [Member]
Impaired loans with no related allowance, interest income recognized	2	1	3	3
Impaired loans with no related allowance, average recorded investment	237	321	411	325
Impaired loans with a related allowance, interest income recognized		38		53
Impaired loans with a related allowance, average recorded investment		2,352		1,332
Commercial Portfolio Segment [Member] \| Multi-family Residential [Member]
Impaired loans with no related allowance, interest income recognized		3	10	3
Impaired loans with no related allowance, average recorded investment	296	557	547	457
Commercial Portfolio Segment [Member] \| Single Family Non-owner Occupied [Member]
Impaired loans with no related allowance, interest income recognized	25	34	48	77
Impaired loans with no related allowance, average recorded investment	2,307	3,308	2,634	3,317
Impaired loans with a related allowance, interest income recognized		5	7	13
Impaired loans with a related allowance, average recorded investment		344	439	344
Commercial Portfolio Segment [Member] \| Non-farm, Non-residential [Member]
Impaired loans with no related allowance, interest income recognized		21	39	25
Impaired loans with no related allowance, average recorded investment	4,048	3,330	5,579	3,027
Impaired loans with a related allowance, interest income recognized		5		15
Impaired loans with a related allowance, average recorded investment	1,374	867	770	1,011
Commercial Portfolio Segment [Member] \| Agricultural [Member]
Impaired loans with no related allowance, interest income recognized
Impaired loans with no related allowance, average recorded investment	175	128	229	127
Commercial Portfolio Segment [Member] \| Farmland [Member]
Impaired loans with no related allowance, interest income recognized	6		15
Impaired loans with no related allowance, average recorded investment	1,336	1,003	887	1,005
Impaired loans with a related allowance, interest income recognized
Impaired loans with a related allowance, average recorded investment	409	411	407	205
Consumer Real Estate Portfolio Segment [Member] \| Home Equity Lines [Member]
Impaired loans with no related allowance, interest income recognized	10	5	17	20
Impaired loans with no related allowance, average recorded investment	1,837	1,052	1,822	1,047
Impaired loans with a related allowance, interest income recognized	2		2
Impaired loans with a related allowance, average recorded investment	68		70	209
Consumer Real Estate Portfolio Segment [Member] \| Single Family Owner Occupied [Member]
Impaired loans with no related allowance, interest income recognized	86	93	193	180
Impaired loans with no related allowance, average recorded investment	14,247	15,943	14,917	14,074
Impaired loans with a related allowance, interest income recognized	59	33	91	68
Impaired loans with a related allowance, average recorded investment	7,040	3,393	6,257	4,883
Consumer Real Estate Portfolio Segment [Member] \| Owner Occupied Construction [Member]
Impaired loans with no related allowance, interest income recognized	3	2	6	5
Impaired loans with no related allowance, average recorded investment	292	234	259	233
Impaired loans with a related allowance, interest income recognized
Impaired loans with a related allowance, average recorded investment
Consumer and Other Portfolio Segment [Member] \| Consumer Loans [Member]
Impaired loans with no related allowance, interest income recognized	5	2	6	2
Impaired loans with no related allowance, average recorded investment	$ 207	$ 43	$ 141	$ 46

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5212-111524

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5258-111524

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