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Investment Securities (Securities With Unrealized Losses And Length Of Impairment Period) (Details) - USD ($) $ in Thousands | Jun. 30, 2025 | Dec. 31, 2024
--- | --- | ---
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value, Less than 12 months | $ 840,685 | $ 1,757,431
Unrealized Loss, Less than 12 months | 4,977 | 27,884
Fair Value, Greater than 12 months | 5,621,533 | 6,377,480
Unrealized Loss, Greater than 12 months | 791,327 | 966,650
Debt Securities, Available-for-sale, Unrealized Loss Position | 6,462,218 | 8,134,911
Unrealized Loss on AFS Debt Securities | 796,304 | 994,534
U.S. government and federal agency obligations |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value, Less than 12 months | 690,639 | 1,492,875
Unrealized Loss, Less than 12 months | 4,040 | 24,662
Fair Value, Greater than 12 months | 291,903 | 353,129
Unrealized Loss, Greater than 12 months | 8,709 | 17,197
Debt Securities, Available-for-sale, Unrealized Loss Position | 982,542 | 1,846,004
Unrealized Loss on AFS Debt Securities | 12,749 | 41,859
Government-sponsored enterprise obligations |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value, Less than 12 months | 0 | 0
Unrealized Loss, Less than 12 months | 0 | 0
Fair Value, Greater than 12 months | 44,148 | 42,848
Unrealized Loss, Greater than 12 months | 10,884 | 12,576
Debt Securities, Available-for-sale, Unrealized Loss Position | 44,148 | 42,848
Unrealized Loss on AFS Debt Securities | 10,884 | 12,576
State and municipal obligations [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value, Less than 12 months | 10,292 | 14,860
Unrealized Loss, Less than 12 months | 272 | 230
Fair Value, Greater than 12 months | 690,932 | 724,587
Unrealized Loss, Greater than 12 months | 59,513 | 79,685
Debt Securities, Available-for-sale, Unrealized Loss Position | 701,224 | 739,447
Unrealized Loss on AFS Debt Securities | 59,785 | 79,915
Agency mortgage-backed securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value, Less than 12 months | 1,964 | 3,882
Unrealized Loss, Less than 12 months | 16 | 42
Fair Value, Greater than 12 months | 3,308,242 | 3,409,405
Unrealized Loss, Greater than 12 months | 636,145 | 750,664
Debt Securities, Available-for-sale, Unrealized Loss Position | 3,310,206 | 3,413,287
Unrealized Loss on AFS Debt Securities | 636,161 | 750,706
Non-Agency Mortgage-Backed Securities [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value, Less than 12 months | 0 | 10
Unrealized Loss, Less than 12 months | 0 | 0
Fair Value, Greater than 12 months | 454,609 | 564,637
Unrealized Loss, Greater than 12 months | 40,278 | 56,986
Debt Securities, Available-for-sale, Unrealized Loss Position | 454,609 | 564,647
Unrealized Loss on AFS Debt Securities | 40,278 | 56,986
Asset-backed securities |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value, Less than 12 months | 110,990 | 219,414
Unrealized Loss, Less than 12 months | 479 | 2,371
Fair Value, Greater than 12 months | 701,808 | 1,083,938
Unrealized Loss, Greater than 12 months | 26,682 | 36,824
Debt Securities, Available-for-sale, Unrealized Loss Position | 812,798 | 1,303,352
Unrealized Loss on AFS Debt Securities | 27,161 | 39,195
Total Mortgage And Asset-Backed Securities [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value, Less than 12 months | 112,954 | 223,306
Unrealized Loss, Less than 12 months | 495 | 2,413
Fair Value, Greater than 12 months | 4,464,659 | 5,057,980
Unrealized Loss, Greater than 12 months | 703,105 | 844,474
Debt Securities, Available-for-sale, Unrealized Loss Position | 4,577,613 | 5,281,286
Unrealized Loss on AFS Debt Securities | 703,600 | 846,887
Debt Securities [Member] |  |
Debt Securities, Available-for-sale [Line Items] |  |
Fair Value, Less than 12 months | 26,800 | 26,390
Unrealized Loss, Less than 12 months | 170 | 579
Fair Value, Greater than 12 months | 129,891 | 198,936
Unrealized Loss, Greater than 12 months | 9,116 | 12,718
Debt Securities, Available-for-sale, Unrealized Loss Position | 156,691 | 225,326
Unrealized Loss on AFS Debt Securities | $ 9,286 | $ 13,297

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