Note 3 - Loans and Allowance for Credit Losses (Details Textual) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2026	Sep. 30, 2025	Dec. 31, 2025
Financing Receivable, before Allowance for Credit Loss	$ 4,952,942		$ 4,821,888
Increase (Decrease) in Finance Receivables	$ 131,000
Loans and Leases Receivable, Percentage Period Increase (Decrease)	2.70%
Financing Receivable, Nonaccrual, Interest Income	$ 1,300	$ 500
Financing Receivable, Revolving, Converted to Term Loan During Period	5,600		700
Financing Receivable, Allowance for Credit Loss, Period Increase (Decrease) From Forecast Changes	(200)		(300)
Financing Receivable, Individually Evaluated for Credit Loss	9,700		7,900
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	2,600		4,000
Commercial Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss	$ 4,070,778		$ 3,918,662
Financing Receivables, Prepayment Speed Assumed	2.00%		2.00%
Retail Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss	$ 882,164		$ 903,226
Retail Portfolio Segment [Member] \| One to Four Family Mortgages [Member]
Financing Receivable, before Allowance for Credit Loss	$ 763,715		$ 790,857
Financing Receivables, Prepayment Speed Assumed	11.60%		9.50%
Retail Portfolio Segment [Member] \| Other Consumer Loans [Member]
Financing Receivable, before Allowance for Credit Loss	$ 118,449		$ 112,369
Financing Receivables, Prepayment Speed Assumed	11.60%		9.50%

Amount of increase (decrease) in allowance for credit loss on financing receivable due economic forecast changes.

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Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

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Percentage of prepayment speed assumed under financing receivables.

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The percentage of increase or (decrease) during the period in loans and leases receivable during the period.

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Amount of financing receivable individually evaluated for credit loss. Excludes financing receivable collectively evaluated for credit loss.

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Amount of interest income on financing receivable on nonaccrual status.

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Amount of increase in term loan from conversion of revolving financing receivable.

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The increase (decrease) during the reporting period in outstanding loans including accrued interest.

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Amortized cost, before allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease.

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