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Note 7 - Investment Securities (Details Textual) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss	$ 4,300		$ 4,300		$ 4,600
Equity Securities, FV-NI, Unrealized Gain (Loss)	(1,400)	$ (1,400)	(5,581)	$ (10,457)
Equity Securities, FV-NI, Decrease in Unrealized Loss			(4,900)
Equity Securities, FV-NI, Current	$ 28,849		$ 28,849		$ 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, Excluding Accrued Interest	$ 0		$ 0
Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss, Not to Sell before Recovery, Credit Loss, Previously Recorded, Expense (Reversal)			0
Debt Securities, Available-for-Sale, Excluding Accrued Interest	1,648,433		1,648,433		$ 1,547,128
Asset Pledged as Collateral [Member] | Public Deposits and Other Borrowings [Member]
Debt Securities, Available-for-Sale, Excluding Accrued Interest	$ 17,700		$ 17,700		$ 17,800
Collateralized Mortgage-Backed Securities [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions	147		147		154
Debt Securities, Available-for-Sale, Excluding Accrued Interest	$ 658,431		$ 658,431		$ 684,016
Corporate Debt Securities [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions	14		14		16
Debt Securities, Available-for-Sale, Excluding Accrued Interest	$ 189,892		$ 189,892		$ 207,945
US Treasury Securities [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions	11		11
Debt Securities, Available-for-Sale, Excluding Accrued Interest	$ 768,249		$ 768,249		$ 621,462
US Government Corporations and Agencies Securities [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions	8		8		9
Debt Securities, Available-for-Sale, Excluding Accrued Interest	$ 7,934		$ 7,934		$ 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, Excluding Accrued Interest	$ 23,927		$ 23,927		$ 24,556

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