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Note 4 - Securities - Investment Securities Continuous Unrealized Loss Position (Details) - USD ($) $ in Thousands | Jun. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Debt securities available for sale, less than twelve months, gross unrealized losses | $ 743 | $ 1,758
Debt securities available for sale, less than twelve months, fair value | 92,270 | 276,720
Debt Securities Available for Sale, Twelve Months or More, Gross Unrealized Losses | 26,986 | 44,570
Debt Securities, Available for Sale, Twelve Months or More, Fair Value | 365,236 | 472,739
Debt Securities, Available for Sale, Gross Unrealized Losses | 27,728 | 46,328
Debt Securities, Available for Sale, Fair Value | 457,506 | 749,459
Debt securities held to maturity, less than twelve months, gross unrealized losses | 202 | 536
Debt securities held to maturity, less than twelve months, fair value | 30,026 | 40,115
Debt securities held to maturity, more than twelve months, gross unrealized losses | 56,476 | 74,835
Debt securities held to maturity, more than twelve months, fair value | 582,375 | 593,233
Debt securities held to maturity, gross unrealized losses | 56,678 | 75,371
Debt securities held to maturity, fair value | 612,400 | 633,348
Total | (56,678) | (75,371)
US Treasury Securities [Member] |  |
Debt securities available for sale, less than twelve months, gross unrealized losses | 37 | 445
Debt securities available for sale, less than twelve months, fair value | 68,554 | 250,547
Debt Securities Available for Sale, Twelve Months or More, Gross Unrealized Losses | (0) | (0)
Debt Securities, Available for Sale, Twelve Months or More, Fair Value | 0 | 0
Debt Securities, Available for Sale, Gross Unrealized Losses | 37 | 445
Debt Securities, Available for Sale, Fair Value | 68,554 | 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, more than twelve months, gross unrealized losses | 13,349 | 19,632
Debt securities held to maturity, more than twelve months, fair value | 236,163 | 229,771
Debt securities held to maturity, gross unrealized losses | 13,349 | 19,632
Debt securities held to maturity, fair value | 236,162 | 229,771
Total | (13,349) | (19,632)
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 | 72 | 577
Debt Securities Available for Sale, Twelve Months or More, Gross Unrealized Losses | 9,610 | 24,204
Debt Securities, Available for Sale, Twelve Months or More, Fair Value | 106,391 | 179,178
Debt Securities, Available for Sale, Gross Unrealized Losses | 9,610 | 24,210
Debt Securities, Available for Sale, Fair Value | 106,463 | 179,755
Debt securities held to maturity, less than twelve months, gross unrealized losses | 125 | 536
Debt securities held to maturity, less than twelve months, fair value | 27,124 | 40,115
Debt securities held to maturity, more than twelve months, gross unrealized losses | 42,779 | 54,614
Debt securities held to maturity, more than twelve months, fair value | 341,693 | 356,215
Debt securities held to maturity, gross unrealized losses | 42,904 | 55,150
Debt securities held to maturity, fair value | 368,817 | 396,330
Total | (42,904) | (55,150)
US States and Political Subdivisions Debt Securities [Member] |  |
Debt securities available for sale, less than twelve months, gross unrealized losses | (0) | (0)
Debt securities available for sale, less than twelve months, fair value | 0 | 0
Debt Securities Available for Sale, Twelve Months or More, Gross Unrealized Losses | 728 | 1,000
Debt Securities, Available for Sale, Twelve Months or More, Fair Value | 9,194 | 9,072
Debt Securities, Available for Sale, Gross Unrealized Losses | 728 | 1,000
Debt Securities, Available for Sale, Fair Value | 9,194 | 9,072
Debt securities held to maturity, less than twelve months, gross unrealized losses | 77 | (0)
Debt securities held to maturity, less than twelve months, fair value | 2,902 | 0
Debt securities held to maturity, more than twelve months, gross unrealized losses | 348 | 589
Debt securities held to maturity, more than twelve months, fair value | 4,519 | 7,247
Debt securities held to maturity, gross unrealized losses | 425 | 589
Debt securities held to maturity, fair value | 7,421 | 7,247
Total | (425) | (589)
Corporate Debt Securities [Member] |  |
Debt securities available for sale, less than twelve months, gross unrealized losses | 706 | 1,307
Debt securities available for sale, less than twelve months, fair value | 23,644 | 25,596
Debt Securities Available for Sale, Twelve Months or More, Gross Unrealized Losses | 16,648 | 19,366
Debt Securities, Available for Sale, Twelve Months or More, Fair Value | 249,651 | 284,489
Debt Securities, Available for Sale, Gross Unrealized Losses | 17,353 | 20,673
Debt Securities, Available for Sale, Fair Value | $ 273,295 | $ 310,085

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