Note 4 - Loans and the Allowance for Loan Losses - Impaired Loans (Details) - USD ($)	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Recorded investment with no related allowance recorded	$ 1,185,000		$ 1,185,000		$ 4,584,000
Recorded investment with an allowance	169,000		169,000		273,000
Impaired Financing Receivable, Related Allowance	21,000		21,000		28,000
Recorded investment	1,354,000		1,354,000		4,857,000
Unpaid principal balance	1,447,000		1,447,000		5,048,000
Average recorded investment			1,369,000	$ 2,610,000	3,369,000
Interest income recognized	16,000	$ 14,000	46,000	$ 45,000	60,000
Commercial Portfolio Segment [Member] \| Commercial Loans [Member]
Recorded investment with no related allowance recorded	0		0		0
Unpaid principal balance with no related allowance recorded	0		0		0
Average recorded investment with no related allowance recorded			0		0
Interest income recognized with no related allowance recorded			0		0
Recorded investment with an allowance	0		0		0
Unpaid principal balance with allowance	0		0		0
Impaired Financing Receivable, Related Allowance	0		0		0
Average recorded investment with an allowance			0		0
Interest income recognized with an allowance			0		0
Recorded investment	0		0		0
Unpaid principal balance	0		0		0
Average recorded investment			0		0
Interest income recognized			0		0
Commercial Portfolio Segment [Member] \| Agricultural Loans [Member]
Recorded investment with no related allowance recorded	234,000		234,000		238,000
Unpaid principal balance with no related allowance recorded	234,000		234,000		238,000
Average recorded investment with no related allowance recorded			236,000		241,000
Interest income recognized with no related allowance recorded			14,000		18,000
Recorded investment with an allowance	0		0		0
Unpaid principal balance with allowance	0		0		0
Impaired Financing Receivable, Related Allowance	0		0		0
Average recorded investment with an allowance			0		0
Interest income recognized with an allowance			0		0
Recorded investment	234,000		234,000		238,000
Unpaid principal balance	234,000		234,000		238,000
Average recorded investment			236,000		241,000
Interest income recognized			14,000		18,000
Commercial Portfolio Segment [Member] \| Real Estate Loan [Member]
Recorded investment with no related allowance recorded	93,000		93,000		3,697,000
Unpaid principal balance with no related allowance recorded	107,000		107,000		3,834,000
Average recorded investment with no related allowance recorded			95,000		2,188,000
Interest income recognized with no related allowance recorded			0		0
Recorded investment with an allowance	0		0		0
Unpaid principal balance with allowance	0		0		0
Impaired Financing Receivable, Related Allowance	0		0		0
Average recorded investment with an allowance			0		0
Interest income recognized with an allowance			0		0
Recorded investment	93,000		93,000		3,697,000
Unpaid principal balance	107,000		107,000		3,834,000
Average recorded investment			95,000		2,188,000
Interest income recognized			0		0
Commercial Portfolio Segment [Member] \| Construction Loans [Member]
Recorded investment with no related allowance recorded	96,000		96,000		0
Unpaid principal balance with no related allowance recorded	96,000		96,000		0
Average recorded investment with no related allowance recorded			99,000		0
Interest income recognized with no related allowance recorded			5,000		0
Recorded investment with an allowance	0		0		102,000
Unpaid principal balance with allowance	0		0		102,000
Impaired Financing Receivable, Related Allowance	0		0		5,000
Average recorded investment with an allowance			0		105,000
Interest income recognized with an allowance			0		6,000
Recorded investment	96,000		96,000		102,000
Unpaid principal balance	96,000		96,000		102,000
Average recorded investment			99,000		105,000
Interest income recognized			5,000		6,000
Residential Portfolio Segment [Member] \| Real Estate Loan [Member]
Recorded investment with no related allowance recorded	514,000		514,000		386,000
Unpaid principal balance with no related allowance recorded	542,000		542,000		399,000
Average recorded investment with no related allowance recorded			514,000		387,000
Interest income recognized with no related allowance recorded			22,000		29,000
Recorded investment with an allowance	169,000		169,000		171,000
Unpaid principal balance with allowance	169,000		169,000		171,000
Impaired Financing Receivable, Related Allowance	21,000		21,000		23,000
Average recorded investment with an allowance			170,000		173,000
Interest income recognized with an allowance			5,000		7,000
Recorded investment	683,000		683,000		557,000
Unpaid principal balance	711,000		711,000		570,000
Average recorded investment			684,000		560,000
Interest income recognized			27,000		36,000
Residential Portfolio Segment [Member] \| Equity Lines of Credit [Member]
Recorded investment with no related allowance recorded	248,000		248,000		263,000
Unpaid principal balance with no related allowance recorded	299,000		299,000		304,000
Average recorded investment with no related allowance recorded			255,000		275,000
Interest income recognized with no related allowance recorded			0		0
Recorded investment with an allowance	0		0		0
Unpaid principal balance with allowance	0		0		0
Impaired Financing Receivable, Related Allowance	0		0		0
Average recorded investment with an allowance			0		0
Interest income recognized with an allowance			0		0
Recorded investment	248,000		248,000		263,000
Unpaid principal balance	299,000		299,000		304,000
Average recorded investment			255,000		275,000
Interest income recognized			0		0
Consumer Portfolio Segment [Member] \| Automobile Loan [Member]
Recorded investment with no related allowance recorded	0		0		0
Unpaid principal balance with no related allowance recorded	0		0		0
Average recorded investment with no related allowance recorded			0		0
Interest income recognized with no related allowance recorded			0		0
Recorded investment with an allowance	0		0		0
Unpaid principal balance with allowance	0		0		0
Impaired Financing Receivable, Related Allowance	0		0		0
Average recorded investment with an allowance			0		0
Interest income recognized with an allowance			0		0
Recorded investment	0		0		0
Unpaid principal balance	0		0		0
Average recorded investment			0		0
Interest income recognized			0		0
Consumer Portfolio Segment [Member] \| Other Loans [Member]
Recorded investment with no related allowance recorded	0		0		0
Unpaid principal balance with no related allowance recorded	0		0		0
Average recorded investment with no related allowance recorded			0		0
Interest income recognized with no related allowance recorded			0		0
Recorded investment with an allowance	0		0		0
Unpaid principal balance with allowance	0		0		0
Impaired Financing Receivable, Related Allowance	0		0		0
Average recorded investment with an allowance			0		0
Interest income recognized with an allowance			0		0
Recorded investment	0		0		0
Unpaid principal balance	$ 0		0		0
Average recorded investment			0		0
Interest income recognized			$ 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 https://asc.fasb.org/extlink&oid=123577603&loc=d3e5212-111524

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