Note 9 - Commitments and Off-balance Sheet Risk (Details Textual) - USD ($) $ in Thousands	Jun. 30, 2025	Mar. 31, 2025	Dec. 31, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023
Financing Receivable, Allowance for Credit Loss	$ 58,375	$ 56,666	$ 54,454	$ 55,408	$ 51,638	$ 49,914
Retail and Commercial Lines of Credit and Credit Card Receivables [Member]
Financing Receivable, Allowance for Credit Loss	$ 900		$ 1,000

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

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Name:	us-gaap_FinancingReceivableAllowanceForCreditLosses
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant