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Note 7 - Investment Securities (Details Textual) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2025 USD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2025 USD ($)	Dec. 31, 2024 USD ($)
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss	$ 3,900		$ 3,900	$ 4,600
Equity Securities, FV-NI, Unrealized Gain (Loss)	(4,191)	$ (9,026)
Equity Securities, FV-NI, Decrease in Unrealized Loss			(4,800)
Equity Securities, FV-NI, Current	$ 30,238		$ 30,238	$ 34,429
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions	183		183	182
Debt Securities, Available-for-Sale, Allowance for Credit Loss	$ 0		$ 0
Debt Securities, Available-for-Sale, Transfer in, Allowance for Credit Loss, Expense	0
Debt Securities, Available-for-Sale	1,434,040		1,434,040	$ 1,547,128
Asset Pledged as Collateral [Member] | Public Deposits and Other Borrowings [Member]
Debt Securities, Available-for-Sale	$ 17,100		$ 17,100	$ 17,800
Collateralized Mortgage-Backed Securities [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions	149		149	154
Debt Securities, Available-for-Sale	$ 679,675		$ 679,675	$ 684,016
Corporate Debt Securities [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions	10		10	16
Debt Securities, Available-for-Sale	$ 179,335		$ 179,335	$ 207,945
US Government Corporations and Agencies Securities [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions	7		7	9
Debt Securities, Available-for-Sale	$ 8,723		$ 8,723	$ 9,149
Collateralized Mortgage Obligations [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions	3		3	3
Debt Securities, Available-for-Sale	$ 24,663		$ 24,663	$ 24,556

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