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Debt Securities (Schedule Of Fair Value And Unrealized Losses Of Securities) (Details) - USD ($) $ in Thousands | Jun. 30, 2025 | Dec. 31, 2024
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Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 2,583,800 | $ 4,123,091
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | (36,285) | (89,623)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 2,835,887 | 2,850,214
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | (423,555) | (501,899)
Debt Securities, Available-for-sale, Unrealized Loss Position | 5,419,687 | 6,973,305
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | (459,840) | (591,522)
U.S. Treasury and agencies |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | 100,399 | 185,042
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | (305) | (2,770)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 768,214 | 794,521
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | (50,017) | (71,077)
Debt Securities, Available-for-sale, Unrealized Loss Position | 868,613 | 979,563
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | (50,322) | (73,847)
Obligations of states and political subdivisions |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | 484,667 | 539,440
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | (8,995) | (8,036)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 273,928 | 224,973
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | (21,207) | (24,225)
Debt Securities, Available-for-sale, Unrealized Loss Position | 758,595 | 764,413
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | (30,202) | (32,261)
Mortgage-backed securities and collateralized mortgage obligations |  |
Debt Securities, Available-for-sale [Line Items] |  |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | 1,998,734 | 3,398,609
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | (26,985) | (78,817)
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 1,793,745 | 1,830,720
Debt Securities, Available-for-Sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | (352,331) | (406,597)
Debt Securities, Available-for-sale, Unrealized Loss Position | 3,792,479 | 5,229,329
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ (379,316) | $ (485,414)

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