| Accumulated Other Comprehensive Income (Loss) [Table Text Block] |
A rollforward of the components of accumulated other comprehensive income (loss) is included as follows (in thousands): | | | | | | | | | | | | | | | | | | | | | | | | | | | Unrealized Gain (Loss) on | | | | | | | | | Available-for-Sale Securities | | Investment Securities Transferred from AFS | | | | | | Total | | Balance, Dec. 31, 2024 | | $ | (412,348) | | | $ | (90,692) | | | | | | | $ | (503,040) | | Net change in unrealized gain (loss) | | 173,828 | | | — | | | | | | | 173,828 | | | | | | | | | | | | | Reclassification adjustments included in earnings: | | | | | | | | | | | | Interest revenue, Investment securities | | — | | | 9,444 | | | | | | | 9,444 | | | | | | | | | | | | | | | | | | | | | | | | | Other comprehensive income (loss), before income taxes | | 173,828 | | | 9,444 | | | | | | | 183,272 | | | Federal and state income taxes | | 40,476 | | | 2,099 | | | | | | | 42,575 | | | Other comprehensive income (loss), net of income taxes | | 133,352 | | | 7,345 | | | | | | | 140,697 | | | Balance, March 31, 2025 | | $ | (278,996) | | | $ | (83,347) | | | | | | | $ | (362,343) | | | | | | | | | | | | | | Balance, Dec. 31, 2025 | | $ | (102,569) | | | $ | (63,601) | | | | | | | $ | (166,170) | | Net change in unrealized gain (loss) | | (84,412) | | | — | | | | | | | (84,412) | | | | | | | | | | | | | Reclassification adjustments included in earnings: | | | | | | | | | | | | Interest revenue, Investment securities | | — | | | 7,376 | | | | | | | 7,376 | | | | | | | | | | | | | | | | | | | | | | | | | Other comprehensive income (loss), before income taxes | | (84,412) | | | 7,376 | | | | | | | (77,036) | | | Federal and state income taxes | | (19,947) | | | 1,743 | | | | | | | (18,204) | | | Other comprehensive income (loss), net of income taxes | | (64,465) | | | 5,633 | | | | | | | (58,832) | | | Balance, March 31, 2026 | | $ | (167,034) | | | $ | (57,968) | | | | | | | $ | (225,002) | |
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