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Note 7 - Investment Securities (Details Textual) $ in Thousands | 3 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Sep. 30, 2025 USD ($) | Sep. 30, 2024 USD ($) | Sep. 30, 2025 USD ($) | Sep. 30, 2024 USD ($) | Dec. 31, 2024 USD ($)
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss | $ 2,800 |  | $ 2,800 |  | $ 4,600
Equity Securities, FV-NI, Unrealized Gain (Loss) | 3,300 | $ 4,300 | (2,318) | $ (6,204) |
Equity Securities, FV-NI, Decrease in Unrealized Loss |  |  | 3,900 |  |
Equity Securities, FV-NI, Current | $ 32,111 |  | $ 32,111 |  | $ 34,429
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions | 169 |  | 169 |  | 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 |  | 0 |  |
Debt Securities, Available-for-Sale, Excluding Accrued Interest | 1,643,450 |  | 1,643,450 |  | $ 1,547,128
Asset Pledged as Collateral [Member] | Public Deposits and Other Borrowings [Member] |  |  |  |  |
Debt Securities, Available-for-Sale, Excluding Accrued Interest | $ 19,500 |  | $ 19,500 |  | $ 17,800
Commercial Mortgage-Backed Securities [Member] |  |  |  |  |
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions | 141 |  | 141 |  |
Corporate Debt Securities [Member] |  |  |  |  |
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions | 12 |  | 12 |  | 16
Debt Securities, Available-for-Sale, Excluding Accrued Interest | $ 165,875 |  | $ 165,875 |  | $ 207,945
US Government Corporations and Agencies Securities [Member] |  |  |  |  |
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions | 11 |  | 11 |  | 9
Debt Securities, Available-for-Sale, Excluding Accrued Interest | $ 6,860 |  | $ 6,860 |  | $ 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 | $ 23,302 |  | $ 23,302 |  | $ 24,556
US Treasury Securities [Member] |  |  |  |  |
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions | 2 |  | 2 |  |
Debt Securities, Available-for-Sale, Excluding Accrued Interest | $ 776,833 |  | $ 776,833 |  | $ 621,462
Collateralized Mortgage-Backed Securities [Member] |  |  |  |  |
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions |  |  |  |  | 154
Debt Securities, Available-for-Sale, Excluding Accrued Interest | $ 645,575 |  | $ 645,575 |  | $ 684,016

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