Note 5 - Loans Receivable - Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Unpaid principal balance - with allowance	$ 1,228	$ 2,114	$ 5,147
Recorded investment - with allowance	1,201	2,022	4,546
Valuation allowance	509	567	1,061
Average recorded investment - with allowance	1,298	3,933	4,589
Interest income recognzied - with allowance	7	7	7
Unpaid principal balance - with no allowance	20,918	24,757	18,202
Recorded investment - with no allowance	16,842	20,158	15,078
Average recorded investment - with no allowance	18,613	16,034	9,056
Interest income recognzied - with no allowance	41	6	7
Unpaid principal balance	22,146	26,871	23,349
Recorded investment	18,043	22,180	19,624
Average recorded investment	19,911	19,967	13,645
Interest income recognzied	48	13	14
Interest based on original terms	1,145	1,360	1,179
Real Estate Portfolio Segment [Member] \| One-to-Four-Family Residential [Member]
Unpaid principal balance - with allowance	240	244	430
Recorded investment - with allowance	215	229	312
Valuation allowance	64	74	83
Average recorded investment - with allowance	223	332	833
Interest income recognzied - with allowance	7	7	7
Unpaid principal balance - with no allowance	9,277	8,704	7,605
Recorded investment - with no allowance	7,035	6,677	6,348
Average recorded investment - with no allowance	6,828	7,074	4,902
Interest income recognzied - with no allowance			1
Real Estate Portfolio Segment [Member] \| Nonfarm Nonresidential [Member]
Unpaid principal balance - with allowance	305		2,728
Recorded investment - with allowance	305		2,395
Valuation allowance	9		522
Average recorded investment - with allowance	61	903	2,651
Interest income recognzied - with allowance
Unpaid principal balance - with no allowance	9,110	11,022	5,352
Recorded investment - with no allowance	7,692	9,421	4,243
Average recorded investment - with no allowance	8,627	5,656	1,759
Interest income recognzied - with no allowance	36
Real Estate Portfolio Segment [Member] \| Farmland [Member]
Unpaid principal balance - with allowance			616
Recorded investment - with allowance			473
Valuation allowance			112
Average recorded investment - with allowance	76	95	479
Interest income recognzied - with allowance
Unpaid principal balance - with no allowance	704	1,226	796
Recorded investment - with no allowance	657	783	499
Average recorded investment - with no allowance	908	740	303
Interest income recognzied - with no allowance
Real Estate Portfolio Segment [Member] \| Construction Loans [Member]
Unpaid principal balance - with allowance	353		215
Recorded investment - with allowance	258		211
Valuation allowance			89
Average recorded investment - with allowance	375	75	152
Interest income recognzied - with allowance	5
Unpaid principal balance - with no allowance		728	686
Recorded investment - with no allowance		539	490
Average recorded investment - with no allowance		593	535
Interest income recognzied - with no allowance		6	6
Real Estate Portfolio Segment [Member] \| Multifamily Residential [Member]
Unpaid principal balance - with no allowance			282
Recorded investment - with no allowance			230
Average recorded investment - with no allowance	48	107	50
Interest income recognzied - with no allowance
Commercial Portfolio Segment [Member]
Unpaid principal balance - with allowance	678	1,865	1,153
Recorded investment - with allowance	676	1,788	1,150
Valuation allowance	431	488	250
Average recorded investment - with allowance	933	2,523	461
Interest income recognzied - with allowance
Unpaid principal balance - with no allowance	1,254	2,893	3,293
Recorded investment - with no allowance	993	2,570	3,085
Average recorded investment - with no allowance	1,641	1,664	1,399
Interest income recognzied - with no allowance
Consumer Portfolio Segment [Member]
Unpaid principal balance - with allowance	5	5	5
Recorded investment - with allowance	5	5	5
Valuation allowance	5	5	5
Average recorded investment - with allowance	5	5	13
Interest income recognzied - with allowance
Unpaid principal balance - with no allowance	220	184	188
Recorded investment - with no allowance	207	168	183
Average recorded investment - with no allowance	186	200	108
Interest income recognzied - with no allowance

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://www.xbrl.org/2003/role/presentationRef
-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://www.xbrl.org/2003/role/presentationRef
-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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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953550-111524

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+ References

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

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-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

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Reflects the amount of additional interest income that would have been recorded if impaired or nonperforming loans were instead current, in compliance with their original terms, and outstanding throughout the reporting period or since origination (if held for part of the period).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82895541&loc=d3e18794-111554

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