Note 4 - Loans - Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Recorded investment	$ 3,641	$ 2,290
Unpaid principal balance	4,475	2,559
Average recorded investment	2,966	1,634
Home Equity Portfolio Segment [Member]
Recorded investment	98	491
Unpaid principal balance	115	522
Average recorded investment	295	367
Consumer Portfolio Segment [Member]
Recorded investment	156	127
Unpaid principal balance	169	181
Average recorded investment	142	140
Commercial Portfolio Segment [Member]
Recorded investment	824	308
Unpaid principal balance	887	310
Average recorded investment	566	208
Agricultural Loan [Member]
Recorded investment	499	32
Unpaid principal balance	756	32
Average recorded investment	266	16
One-to-Four Family Loans [Member] \| Residential Portfolio Segment [Member]
Recorded investment	618	253
Unpaid principal balance	657	277
Average recorded investment	435	364
One-to-Four Family Construction [Member] \| Residential Portfolio Segment [Member]
Recorded investment	337	634
Unpaid principal balance	387	684
Average recorded investment	485	317
Commercial Real Estate Loan [Member] \| Commercial Real Estate Portfolio Segment [Member]
Recorded investment	583	432
Unpaid principal balance	766	527
Average recorded investment	507	216
Construction Loans [Member] \| Commercial Real Estate Portfolio Segment [Member]
Recorded investment	50	13
Unpaid principal balance	225	26
Average recorded investment	32	6
Farmland Loan [Member] \| Commercial Real Estate Portfolio Segment [Member]
Recorded investment	476
Unpaid principal balance	513
Average recorded investment	$ 238

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=118936363&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=118936363&loc=d3e5258-111524

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-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
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