Note 5 - Credit Quality - Average Annual Recorded Investment and Interest Income Recognized on Impaired Loans Excluding Purchased Credit Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Impaired loans with no related allowance, interest income recognized	$ 976	$ 928	$ 986
Impaired loans with no related allowance, average recorded investment	28,495	27,209	27,494
Impaired loans with a related allowance, interest income recognized	172	328	370
Impaired loans with a related allowance, average recorded investment	6,860	8,102	8,996
Total impaired loans, interest income recognized	1,148	1,256	1,356
Total impaired loans, average recorded investment	35,355	35,311	36,490
Commercial Portfolio Segment [Member] \| Construction, Development and Other Land [Member]
Impaired loans with no related allowance, interest income recognized	26	56	22
Impaired loans with no related allowance, average recorded investment	921	455	344
Impaired loans with a related allowance, interest income recognized
Impaired loans with a related allowance, average recorded investment		107
Commercial Portfolio Segment [Member] \| Commercial and Industrial [Member]
Impaired loans with no related allowance, interest income recognized	19	14	16
Impaired loans with no related allowance, average recorded investment	383	556	646
Impaired loans with a related allowance, interest income recognized		103
Impaired loans with a related allowance, average recorded investment		1,376
Commercial Portfolio Segment [Member] \| Multi-family Residential [Member]
Impaired loans with no related allowance, interest income recognized	47	53	21
Impaired loans with no related allowance, average recorded investment	910	523	308
Impaired loans with a related allowance, interest income recognized	2
Impaired loans with a related allowance, average recorded investment	270
Commercial Portfolio Segment [Member] \| Single Family Non-owner Occupied [Member]
Impaired loans with no related allowance, interest income recognized	123	106	178
Impaired loans with no related allowance, average recorded investment	2,652	3,214	3,076
Impaired loans with a related allowance, interest income recognized	7	27	23
Impaired loans with a related allowance, average recorded investment	110	479	518
Commercial Portfolio Segment [Member] \| Non-farm, Non-residential [Member]
Impaired loans with no related allowance, interest income recognized	133	122	307
Impaired loans with no related allowance, average recorded investment	4,828	4,052	8,573
Impaired loans with a related allowance, interest income recognized	2	15	215
Impaired loans with a related allowance, average recorded investment	809	789	3,831
Commercial Portfolio Segment [Member] \| Agricultural [Member]
Impaired loans with no related allowance, interest income recognized		5
Impaired loans with no related allowance, average recorded investment	164	124
Commercial Portfolio Segment [Member] \| Farmland [Member]
Impaired loans with no related allowance, interest income recognized	64	17	55
Impaired loans with no related allowance, average recorded investment	1,172	853	437
Impaired loans with a related allowance, interest income recognized		22	14
Impaired loans with a related allowance, average recorded investment	307	442	108
Consumer Real Estate Portfolio Segment [Member] \| Home Equity Lines [Member]
Impaired loans with no related allowance, interest income recognized	44	50	30
Impaired loans with no related allowance, average recorded investment	1,637	1,365	1,223
Impaired loans with a related allowance, interest income recognized	3
Impaired loans with a related allowance, average recorded investment	68	104
Consumer Real Estate Portfolio Segment [Member] \| Single Family Owner Occupied [Member]
Impaired loans with no related allowance, interest income recognized	503	488	343
Impaired loans with no related allowance, average recorded investment	15,423	15,758	12,330
Impaired loans with a related allowance, interest income recognized	158	161	118
Impaired loans with a related allowance, average recorded investment	5,296	4,805	4,452
Consumer Real Estate Portfolio Segment [Member] \| Owner Occupied Construction [Member]
Impaired loans with no related allowance, interest income recognized	8	8	9
Impaired loans with no related allowance, average recorded investment	244	234	497
Impaired loans with a related allowance, interest income recognized
Impaired loans with a related allowance, average recorded investment			87
Consumer and Other Portfolio Segment [Member] \| Consumer Loans [Member]
Impaired loans with no related allowance, interest income recognized	9	9	5
Impaired loans with no related allowance, average recorded investment	$ 161	$ 75	$ 60

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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