Note 4 - Loans, Allowance for Credit Losses and Credit Quality (Details Textual)	3 Months Ended	12 Months Ended
Mar. 31, 2026 USD ($)	Mar. 31, 2025 USD ($)	Dec. 31, 2025 USD ($)
Financing Receivable, Excluding Accrued Interest, after Allowance for Credit Loss	$ 1,391,489,000		$ 1,371,819,000
Financing Receivable, Accrued Interest, after Allowance for Credit Loss	4,700,000		4,600,000
Financing Receivable, Nonaccrual, Interest Income	16,000	$ 39,000	99,000
Financing Receivable, Excluding Accrued Interest, Modified in Period, Amount	0	$ 0
Commercial Loan [Member]
Financing Receivable, Excluding Accrued Interest, Threshold for Credit Assessement	500,000
Real Estate Loan [Member]
Financing Receivable, Excluding Accrued Interest, Threshold for Credit Assessement	$ 2,000,000
Consumer Loan [Member] \| Residential Real Estate [Member] \| Real Estate Portfolio Segment [Member]
Financing Receivable, Number of Contracts in Process of Foreclosure	1
Mortgage Loans in Process of Foreclosure, Amount	$ 103,000		0
Asset Pledged as Collateral [Member] \| Federal Home Loan Bank Advances [Member]
Financing Receivable, Excluding Accrued Interest, after Allowance for Credit Loss	919,200,000		920,900,000
Asset Pledged as Collateral [Member] \| Federal Reserve Bank [Member]
Financing Receivable, Excluding Accrued Interest, after Allowance for Credit Loss	$ 118,700,000		$ 114,700,000

Represents the threshold for credit assessment.

No definition available.

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- Definition

Number of financing receivables contracts in the process of foreclosure.

+ References

No definition available.

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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
-Paragraph 1
-Publisher FASB
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Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
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-Section 45
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-5

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
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-Name Accounting Standards Codification
-Section 50
-Paragraph 3A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-3A

+ Details

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Data Type:	xbrli:monetaryItemType
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- Definition

Amortized cost excluding accrued interest, after allowance for credit loss, of financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477657/942-210-S45-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
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-URI https://asc.fasb.org/1943274/2147478478/942-210-S50-1

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
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-Name Accounting Standards Codification
-Section S99
-Paragraph 1
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
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-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

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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
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-42

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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
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

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- Definition

Recorded investment of consumer mortgage loan receivables secured by residential real estate properties for which formal foreclosure proceedings are in process.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 35
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-35

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- Details

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- Details

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