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Investments (Number of Securities in an Unrealized Unrecognized Loss Position) (Details) - Available-for-sale Securities [Member] - USD ($) $ in Thousands | Dec. 31, 2021 | Dec. 31, 2020
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Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | $ 1,376,128 | $ 415,506
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 14,849 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 85,122 | 185,335
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss |  | 6,108
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 2,505 | 5,434
Debt Securities, Available-for-sale, Unrealized Loss Position | 1,461,250 | 600,841
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | 17,354 | 11,542
U.S. Government and Government Agencies [Member] |  |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | 34,857 | 11,519
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 746 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 7,827 | 0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss |  | 137
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 399 | 0
Debt Securities, Available-for-sale, Unrealized Loss Position | 42,684 | 11,519
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | 1,145 | 137
Foreign Government [Member] |  |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | 2,000 | 1,122
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 84 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 1,061 | 0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss |  | 3
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 39 | 0
Debt Securities, Available-for-sale, Unrealized Loss Position | 3,061 | 1,122
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | 123 | 3
Obligations of States and Political Subdivisions [Member] |  |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | 25,837 | 2,223
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 235 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 0 | 0
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss |  | 11
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 0 | 0
Debt Securities, Available-for-sale, Unrealized Loss Position | 25,837 | 2,223
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | 235 | 11
Corporate Securities [Member] |  |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | 300,549 | 65,187
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 4,903 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 2,520 | 2,400
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss |  | 2,152
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 50 | 188
Debt Securities, Available-for-sale, Unrealized Loss Position | 303,069 | 67,587
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | 4,953 | 2,340
Collateralized Loan Obligations and Other Asset-Backed Securities [Member] |  |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | 663,976 | 261,746
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 4,934 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 53,368 | 165,661
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss |  | 2,995
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 1,350 | 4,848
Debt Securities, Available-for-sale, Unrealized Loss Position | 717,344 | 427,407
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | 6,284 | 7,843
Residential Mortgage Backed Securities [Member] |  |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | 236,010 | 18,227
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 2,931 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 20 | 1,181
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss |  | 194
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 1 | 7
Debt Securities, Available-for-sale, Unrealized Loss Position | 236,030 | 19,408
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | 2,932 | 201
Commercial Mortgage Backed Securities [Member] |  |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months | 112,899 | 55,482
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss | 1,016 |
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer | 20,326 | 16,093
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss |  | 616
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss | 666 | 391
Debt Securities, Available-for-sale, Unrealized Loss Position | 133,225 | 71,575
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss | $ 1,682 | $ 1,007

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