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Note 2 - Debt Securities - Investment Securities Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands | Dec. 31, 2025 | Dec. 31, 2024
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Debt securities available for sale, less than twelve months, gross unrealized losses | $ (984) | $ (1,758)
Debt securities available for sale, less than twelve months, fair value | 77,583 | 276,720
Debt Securities Available for Sale, Twelve Months or More, Gross Unrealized Losses | (9,632) | (44,570)
Debt Securities, Available for Sale, Twelve Months or More, Fair Value | 187,749 | 472,739
Debt Securities, Available for Sale, Gross Unrealized Losses | (10,616) | (46,328)
Debt Securities, Available for Sale, Fair Value | 265,332 | 749,459
Debt Securities held to maturity less than twelve months, gross unrealized losses | (34) | (536)
Debt securities, held to maturity, Less Than Twelve Months, Fair Value | 2,954 | 40,115
Debt Securities Held To Maturity, Twelve Months or More, Gross Unrealized Losses | (44,250) | (74,835)
Debt Securities, Held To Maturity, Twelve Months or More, Fair Value | 569,943 | 593,233
Debt Securities, Held To Maturity , Gross Unrealized Losses | (44,284) | (75,371)
Debt Securities, Held To Maturity, Fair Value | 572,897 | 633,348
US Treasury Securities [Member] |  |
Debt securities available for sale, less than twelve months, gross unrealized losses | 0 | (445)
Debt securities available for sale, less than twelve months, fair value | 0 | 250,547
Debt Securities Available for Sale, Twelve Months or More, Gross Unrealized Losses | (852) | 0
Debt Securities, Available for Sale, Twelve Months or More, Fair Value | 22,662 | 0
Debt Securities, Available for Sale, Gross Unrealized Losses | (852) | (445)
Debt Securities, Available for Sale, Fair Value | 22,662 | 250,547
Debt Securities held to maturity less than twelve months, gross unrealized losses | 0 | 0
Debt securities, held to maturity, Less Than Twelve Months, Fair Value | 0 | 0
Debt Securities Held To Maturity, Twelve Months or More, Gross Unrealized Losses | (9,589) | (19,632)
Debt Securities, Held To Maturity, Twelve Months or More, Fair Value | 240,032 | 229,771
Debt Securities, Held To Maturity , Gross Unrealized Losses | (9,589) | (19,632)
Debt Securities, Held To Maturity, Fair Value | 240,032 | 229,771
Collateralized Mortgage-Backed Securities [Member] |  |
Debt securities available for sale, less than twelve months, gross unrealized losses | 0 | (6)
Debt securities available for sale, less than twelve months, fair value | 0 | 577
Debt Securities Available for Sale, Twelve Months or More, Gross Unrealized Losses | (554) | (24,204)
Debt Securities, Available for Sale, Twelve Months or More, Fair Value | 9,363 | 179,178
Debt Securities, Available for Sale, Gross Unrealized Losses | (554) | (24,210)
Debt Securities, Available for Sale, Fair Value | 9,363 | 179,755
Debt Securities held to maturity less than twelve months, gross unrealized losses | 0 | (536)
Debt securities, held to maturity, Less Than Twelve Months, Fair Value | 0 | 40,115
Debt Securities Held To Maturity, Twelve Months or More, Gross Unrealized Losses | (34,395) | (54,614)
Debt Securities, Held To Maturity, Twelve Months or More, Fair Value | 325,307 | 356,215
Debt Securities, Held To Maturity , Gross Unrealized Losses | (34,395) | (55,150)
Debt Securities, Held To Maturity, Fair Value | 325,307 | 396,330
Corporate Debt Securities [Member] |  |
Debt securities available for sale, less than twelve months, gross unrealized losses | (984) | (1,307)
Debt securities available for sale, less than twelve months, fair value | 77,583 | 25,596
Debt Securities Available for Sale, Twelve Months or More, Gross Unrealized Losses | (8,226) | (19,366)
Debt Securities, Available for Sale, Twelve Months or More, Fair Value | 155,724 | 284,489
Debt Securities, Available for Sale, Gross Unrealized Losses | (9,210) | (20,673)
Debt Securities, Available for Sale, Fair Value | 233,307 | 310,085
US States and Political Subdivisions Debt Securities [Member] |  |
Debt securities available for sale, less than twelve months, gross unrealized losses |  | 0
Debt securities available for sale, less than twelve months, fair value |  | 0
Debt Securities Available for Sale, Twelve Months or More, Gross Unrealized Losses |  | (1,000)
Debt Securities, Available for Sale, Twelve Months or More, Fair Value |  | 9,072
Debt Securities, Available for Sale, Gross Unrealized Losses |  | (1,000)
Debt Securities, Available for Sale, Fair Value |  | 9,072
Debt Securities held to maturity less than twelve months, gross unrealized losses | (34) | 0
Debt securities, held to maturity, Less Than Twelve Months, Fair Value | 2,954 | 0
Debt Securities Held To Maturity, Twelve Months or More, Gross Unrealized Losses | (266) | (589)
Debt Securities, Held To Maturity, Twelve Months or More, Fair Value | 4,604 | 7,247
Debt Securities, Held To Maturity , Gross Unrealized Losses | (300) | (589)
Debt Securities, Held To Maturity, Fair Value | $ 7,558 | $ 7,247

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