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Investment Securities - Schedule of Available-for-sale Investment Securities Portfolios (Details) - USD ($) | Jun. 30, 2025 | Dec. 31, 2024 | Jun. 30, 2024
--- | --- | --- | ---
Available-for-sale securities |  |  |
Continuous unrealized losses existing for less than 12 months, fair value | $ 1,176,440,000 |  |
Continuous unrealized losses existing for less than 12 months, unrealized losses | (16,863,000) |  |
Continuous unrealized losses existing for greater than 12 months, fair value | 2,424,427,000 |  |
Continuous unrealized losses existing for greater than 12 months, unrealized losses | (493,712,000) |  |
Total, fair value | 3,600,867,000 |  |
Total, unrealized losses | (510,575,000) |  |
Available-for-sale securities, at fair value | 4,885,715,000 | $ 4,141,482,000 | $ 4,329,957,000
U.S. Treasury |  |  |
Available-for-sale securities |  |  |
Continuous unrealized losses existing for less than 12 months, fair value | 0 |  |
Continuous unrealized losses existing for less than 12 months, unrealized losses | 0 |  |
Continuous unrealized losses existing for greater than 12 months, fair value | 0 |  |
Continuous unrealized losses existing for greater than 12 months, unrealized losses | 0 |  |
Total, fair value | 0 |  |
Total, unrealized losses | 0 |  |
Available-for-sale securities, at fair value | 13,018,000 | 37,907,000 | 102,712,000
U.S. government agencies |  |  |
Available-for-sale securities |  |  |
Continuous unrealized losses existing for less than 12 months, fair value | 0 |  |
Continuous unrealized losses existing for less than 12 months, unrealized losses | 0 |  |
Continuous unrealized losses existing for greater than 12 months, fair value | 45,824,000 |  |
Continuous unrealized losses existing for greater than 12 months, unrealized losses | (4,176,000) |  |
Total, fair value | 45,824,000 |  |
Total, unrealized losses | (4,176,000) |  |
Available-for-sale securities, at fair value | 45,824,000 | 44,945,000 | 45,192,000
Municipal |  |  |
Available-for-sale securities |  |  |
Continuous unrealized losses existing for less than 12 months, fair value | 46,160,000 |  |
Continuous unrealized losses existing for less than 12 months, unrealized losses | (720,000) |  |
Continuous unrealized losses existing for greater than 12 months, fair value | 50,763,000 |  |
Continuous unrealized losses existing for greater than 12 months, unrealized losses | (2,517,000) |  |
Total, fair value | 96,923,000 |  |
Total, unrealized losses | (3,237,000) |  |
Available-for-sale securities, at fair value | 180,644,000 | 184,593,000 | 146,608,000
Financial issuers |  |  |
Available-for-sale securities |  |  |
Continuous unrealized losses existing for less than 12 months, fair value | 0 |  |
Continuous unrealized losses existing for less than 12 months, unrealized losses | 0 |  |
Continuous unrealized losses existing for greater than 12 months, fair value | 78,801,000 |  |
Continuous unrealized losses existing for greater than 12 months, unrealized losses | (3,199,000) |  |
Total, fair value | 78,801,000 |  |
Total, unrealized losses | (3,199,000) |  |
Available-for-sale securities, at fair value | 78,801,000 | 80,169,000 | 76,985,000
Other |  |  |
Available-for-sale securities |  |  |
Continuous unrealized losses existing for less than 12 months, fair value | 0 |  |
Continuous unrealized losses existing for less than 12 months, unrealized losses | 0 |  |
Continuous unrealized losses existing for greater than 12 months, fair value | 998,000 |  |
Continuous unrealized losses existing for greater than 12 months, unrealized losses | (2,000) |  |
Total, fair value | 998,000 |  |
Total, unrealized losses | (2,000) |  |
Available-for-sale securities, at fair value | 998,000 | 993,000 | 990,000
Residential mortgage-backed securities |  |  |
Available-for-sale securities |  |  |
Continuous unrealized losses existing for less than 12 months, fair value | 1,037,618,000 |  |
Continuous unrealized losses existing for less than 12 months, unrealized losses | (12,905,000) |  |
Continuous unrealized losses existing for greater than 12 months, fair value | 2,177,836,000 |  |
Continuous unrealized losses existing for greater than 12 months, unrealized losses | (465,863,000) |  |
Total, fair value | 3,215,454,000 |  |
Total, unrealized losses | (478,768,000) |  |
Available-for-sale securities, at fair value | 4,143,684,000 | 3,553,638,000 | 3,778,834,000
Commercial (multi-family) mortgage-backed securities |  |  |
Available-for-sale securities |  |  |
Continuous unrealized losses existing for less than 12 months, fair value | 92,662,000 |  |
Continuous unrealized losses existing for less than 12 months, unrealized losses | (3,238,000) |  |
Continuous unrealized losses existing for greater than 12 months, fair value | 6,107,000 |  |
Continuous unrealized losses existing for greater than 12 months, unrealized losses | (396,000) |  |
Total, fair value | 98,769,000 |  |
Total, unrealized losses | (3,634,000) |  |
Available-for-sale securities, at fair value | 126,945,000 | 18,332,000 | 17,478,000
Collateralized mortgage obligations |  |  |
Available-for-sale securities |  |  |
Continuous unrealized losses existing for less than 12 months, fair value | 0 |  |
Continuous unrealized losses existing for less than 12 months, unrealized losses | 0 |  |
Continuous unrealized losses existing for greater than 12 months, fair value | 64,098,000 |  |
Continuous unrealized losses existing for greater than 12 months, unrealized losses | (17,559,000) |  |
Total, fair value | 64,098,000 |  |
Total, unrealized losses | (17,559,000) |  |
Available-for-sale securities, at fair value | 295,801,000 | 220,905,000 | 161,158,000
Mortgage-backed securities, subprime |  |  |
Available-for-sale securities |  |  |
Available-for-sale securities, at fair value | $ 0 | $ 0 | $ 0

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