Note 4 - Loans - Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Unpaid contractual principal	$ 1,185	$ 1,269
Recorded investment with no allowance	248	14
Recorded investment with allowance	855	906
Total recorded investment	1,103	920
Related allowance	680	680
Average recorded investment	1,005	1,148
Commercial Real Estate Portfolio Segment [Member] \| Construction Loans [Member]
Unpaid contractual principal	0	0
Recorded investment with no allowance	0	0
Recorded investment with allowance	0	0
Total recorded investment	0	0
Related allowance	0	0
Average recorded investment	0	0
Commercial Real Estate Portfolio Segment [Member] \| Mortgage Loans [Member]
Unpaid contractual principal	0	0
Recorded investment with no allowance	0	0
Recorded investment with allowance	0	0
Total recorded investment	0	0
Related allowance	0	0
Average recorded investment	0	0
Commercial Real Estate Portfolio Segment [Member] \| Land Loans [Member]
Unpaid contractual principal	873	1,222
Recorded investment with no allowance	0	0
Recorded investment with allowance	855	906
Total recorded investment	855	906
Related allowance	680	680
Average recorded investment	892	958
Commercial Real Estate Portfolio Segment [Member] \| Farmland Loans [Member]
Unpaid contractual principal	0	0
Recorded investment with no allowance	0	0
Recorded investment with allowance	0	0
Total recorded investment	0	0
Related allowance	0	0
Average recorded investment	0	0
Commercial Portfolio Segment [Member]
Unpaid contractual principal	0	32
Recorded investment with no allowance	0	0
Recorded investment with allowance	0	0
Total recorded investment	0	0
Related allowance	0	0
Average recorded investment	0	176
Consumer Portfolio Segment [Member]
Unpaid contractual principal	0	0
Recorded investment with no allowance	0	0
Recorded investment with allowance	0	0
Total recorded investment	0	0
Related allowance	0	0
Average recorded investment	0	0
Residential Portfolio Segment [Member]
Unpaid contractual principal	312	15
Recorded investment with no allowance	248	14
Recorded investment with allowance	0	0
Total recorded investment	248	14
Related allowance	0	0
Average recorded investment	113	14
Agriculture [Member]
Unpaid contractual principal	0	0
Recorded investment with no allowance	0	0
Recorded investment with allowance	0	0
Total recorded investment	0	0
Related allowance	0	0
Average recorded investment	$ 0	$ 0

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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+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=118936363&loc=SL6953550-111524

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