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Investment Securities - Securities with gross unrealized losses (Details) - USD ($) $ in Thousands | Jun. 30, 2025 | Dec. 31, 2024
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Securities Held to Maturity, Gross Unrealized Losses |  |
Twelve Months or More | $ 364,243 | $ 420,143
Securities Held to Maturity, Fair Value |  |
Twelve Months or More | 1,781,748 | 1,834,527
Securities Available for Sale, Gross Unrealized Losses |  |
Less Than Twelve Months | 3,487 | 2,594
Twelve Months or More | 517,629 | 806,730
Securities Available for Sale, Fair Value |  |
Less Than Twelve Months | 662,372 | 93,830
Twelve Months or More | 2,687,664 | 4,113,658
U.S. Government agencies |  |
Securities Held to Maturity, Gross Unrealized Losses |  |
Twelve Months or More | 19,050 | 23,498
Securities Held to Maturity, Fair Value |  |
Twelve Months or More | 113,860 | 123,774
Securities Available for Sale, Gross Unrealized Losses |  |
Twelve Months or More |  | 18,789
Securities Available for Sale, Fair Value |  |
Twelve Months or More |  | 150,418
Residential mortgage-backed securities issued by U.S. government agencies or sponsored enterprises |  |
Securities Held to Maturity, Gross Unrealized Losses |  |
Twelve Months or More | 209,197 | 241,204
Securities Held to Maturity, Fair Value |  |
Twelve Months or More | 1,016,900 | 1,056,339
Securities Available for Sale, Gross Unrealized Losses |  |
Less Than Twelve Months | 1,267 | 294
Twelve Months or More | 166,010 | 282,129
Securities Available for Sale, Fair Value |  |
Less Than Twelve Months | 96,348 | 14,341
Twelve Months or More | 838,193 | 1,350,268
Residential collateralized mortgage-obligations issued by U.S. government agencies or sponsored enterprises |  |
Securities Held to Maturity, Gross Unrealized Losses |  |
Twelve Months or More | 62,090 | 72,057
Securities Held to Maturity, Fair Value |  |
Twelve Months or More | 333,259 | 339,664
Securities Available for Sale, Gross Unrealized Losses |  |
Less Than Twelve Months | 1,627 |
Twelve Months or More | 54,181 | 98,212
Securities Available for Sale, Fair Value |  |
Less Than Twelve Months | 398,768 |
Twelve Months or More | 308,971 | 454,908
Commercial mortgage-backed securities issued by U.S. government agencies or sponsored enterprises |  |
Securities Held to Maturity, Gross Unrealized Losses |  |
Twelve Months or More | 64,067 | 72,391
Securities Held to Maturity, Fair Value |  |
Twelve Months or More | 279,886 | 275,947
Securities Available for Sale, Gross Unrealized Losses |  |
Less Than Twelve Months | 135 | 792
Twelve Months or More | 81,585 | 193,788
Securities Available for Sale, Fair Value |  |
Less Than Twelve Months | 39,092 | 53,342
Twelve Months or More | 414,247 | 918,338
State and municipal obligations |  |
Securities Available for Sale, Gross Unrealized Losses |  |
Less Than Twelve Months | 315 | 1,484
Twelve Months or More | 185,899 | 170,125
Securities Available for Sale, Fair Value |  |
Less Than Twelve Months | 6,672 | 19,400
Twelve Months or More | 881,624 | 923,431
Small Business Administration loan-backed securities |  |
Securities Held to Maturity, Gross Unrealized Losses |  |
Twelve Months or More | 9,839 | 10,993
Securities Held to Maturity, Fair Value |  |
Twelve Months or More | 37,843 | 38,803
Securities Available for Sale, Gross Unrealized Losses |  |
Less Than Twelve Months | 143 | 24
Twelve Months or More | 28,049 | 41,697
Securities Available for Sale, Fair Value |  |
Less Than Twelve Months | 121,492 | 6,747
Twelve Months or More | 218,036 | 289,786
Corporate securities |  |
Securities Available for Sale, Gross Unrealized Losses |  |
Twelve Months or More | 1,905 | 1,990
Securities Available for Sale, Fair Value |  |
Twelve Months or More | $ 26,593 | $ 26,509

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