Note 4 - Loans (Details Textual)	3 Months Ended
Mar. 31, 2026 USD ($)	Mar. 31, 2025 USD ($)	Dec. 31, 2025 USD ($)
Financing Receivable, before Allowance for Credit Loss, to Total, Percent	22.00%		22.00%
Financing Receivable, Accrued Interest, after Allowance for Credit Loss	$ 3,567,000		$ 3,510,000
Underwriting Standards, Loan to Value Percentage	80.00%
Underwriting Standards, Housing Percentage	36.00%
Underwriting Standards, Total Debt Ratio	42.00%
Financing Receivable, Nonaccrual, Interest Income	$ 50,000
Financing Receivable, Excluding Accrued Interest, Nonaccrual			0
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process	1,147,451,000		1,143,930,000
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	$ 0	$ 0
Exceptional [Member]
Financing Receivable, Minimum Cash Collateral Percent	110.00%
Better Than Acceptable [Member] \| Minimum [Member]
Financing Receivable, Loan-to-value on Real Estate Secured Transactions	10.00%
Better Than Acceptable [Member] \| Maximum [Member]
Financing Receivable, Loan-to-value on Real Estate Secured Transactions	20.00%
Unlikely to be Collected Financing Receivable [Member]
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process	$ 0		$ 0
Commercial Real Estate [Member]
Number of Collateral Dependent Loans	1		1
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process	$ 4,574,000		$ 4,587,000
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss, to Total, Percent	88.00%
Commercial Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss, to Total, Percent	6.00%
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process	$ 68,207,000		70,262,000
Residential Real Estate and Other Consumer Loans [Member]
Financing Receivable, before Allowance for Credit Loss, to Total, Percent	3.00%
Agriculture [Member]
Financing Receivable, before Allowance for Credit Loss, to Total, Percent	3.00%
Financing Receivable, Excluding Accrued Interest, before Allowance for Credit Loss, Fee, and Loan in Process	$ 31,377,000		$ 29,006,000

Percentage of loan to value on real estate secured transactions.

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- Definition

The percentage of the loan amount for which cash collateral must be equal to or greater than in order for the loan to properly margined.

+ References

No definition available.

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- Definition

Represents the number of collateral dependent loans.

+ References

No definition available.

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- Definition

Represents the housing percentage as per the underwriting standards.

+ References

No definition available.

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- Definition

Represents the loan-to-value percentage as per the underwriting standards.

+ References

No definition available.

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- Definition

Represents the total debt ratio as per the underwriting standards.

+ References

No definition available.

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- Definition

Percentage, before allowance for credit loss, of financing receivable to total financing receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph c
-Publisher SEC

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- Definition

Amount, after allowance for credit loss, of accrued interest on financing receivable.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S45
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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 4: http://www.xbrl.org/2003/role/disclosureRef
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- Definition

Amortized cost excluding accrued interest, before allowance for credit loss, fee, and loan in process, of financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
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- Definition

Amortized cost excluding accrued interest, of financing receivable modified during period for debtor experiencing financial difficulty.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Subparagraph (a)(1)
-Publisher FASB
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- Definition

Amortized cost excluding accrued interest, of financing receivable on nonaccrual status. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
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- Definition

Amount of interest income on financing receivable on nonaccrual status.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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-SubTopic 20
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