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Note 3 - Loans and Allowance for Credit Losses (Details Textual) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2025 | Mar. 31, 2024 | Dec. 31, 2024
Financing Receivable, before Allowance for Credit Loss | $ 4,636,549 |  | $ 4,600,781
Increase (Decrease) in Finance Receivables | $ 35,800 |  |
Loans and Leases Receivable, Percentage Period Increase (Decrease) | 0.80% |  |
Financing Receivable, Nonaccrual, Interest Income | $ 300 | $ 200 |
Financing Receivable, Revolving, Converted to Term Loan During Period | 300 |  | 9,100
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease) From Forecast Changes | (100) |  | (2,200)
Financing Receivable, Individually Evaluated for Credit Loss | 7,000 |  | 7,400
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment | $ 2,400 |  | 2,200
Financing Receivable, Modifications, Number of Contracts | 0 |  |
Commercial Portfolio Segment [Member] |  |  |
Financing Receivable, before Allowance for Credit Loss | $ 3,751,591 |  | $ 3,707,304
Financing Receivables, Prepayment Speed Assumed | 2.00% |  | 2.00%
Retail Portfolio Segment [Member] |  |  |
Financing Receivable, before Allowance for Credit Loss | $ 884,958 |  | $ 893,477
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member] |  |  |
Financing Receivable, before Allowance for Credit Loss | $ 817,212 |  | $ 827,597
Financing Receivables, Prepayment Speed Assumed | 7.80% |  | 7.80%
Retail Portfolio Segment [Member] | Other Consumer Loans [Member] |  |  |
Financing Receivable, before Allowance for Credit Loss | $ 67,746 |  | $ 65,880
Financing Receivables, Prepayment Speed Assumed | 7.80% |  | 7.80%

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- Definition Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment. + References No definition available. + Details
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