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Reserves For Losses And Loss Expenses (Loss and Loss Expenses Incurred, Net of Reinsurance, and Cumulative Paid Claims and Claim Adjustment Expenses, Net of Reinsurance) (Details) $ in Thousands | Dec. 31, 2023 USD ($) claim | Dec. 31, 2022 USD ($) | Dec. 31, 2021 USD ($) | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($) | Dec. 31, 2014 USD ($)
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Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Reserves for loss and loss adjustment expenses, net of reinsurance | $ 16,051,744 |  |  |  |  |  |  |  |  |
Other liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 13,419,768 |  |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 7,202,094 |  |  |  |  |  |  |  |  |
Reserves for loss and loss adjustment expenses before 2014, net of reinsurance | 154,001 |  |  |  |  |  |  |  |  |
Reserves for loss and loss adjustment expenses, net of reinsurance | 6,371,675 |  |  |  |  |  |  |  |  |
Workers' compensation |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 6,813,772 |  |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 5,209,715 |  |  |  |  |  |  |  |  |
Reserves for loss and loss adjustment expenses before 2014, net of reinsurance | 208,451 |  |  |  |  |  |  |  |  |
Reserves for loss and loss adjustment expenses, net of reinsurance | 1,812,508 |  |  |  |  |  |  |  |  |
Professional liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 4,149,302 |  |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 2,216,817 |  |  |  |  |  |  |  |  |
Reserves for loss and loss adjustment expenses before 2014, net of reinsurance | 38,814 |  |  |  |  |  |  |  |  |
Reserves for loss and loss adjustment expenses, net of reinsurance | 1,971,299 |  |  |  |  |  |  |  |  |
Auto |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 5,647,754 |  |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 4,197,877 |  |  |  |  |  |  |  |  |
Reserves for loss and loss adjustment expenses before 2014, net of reinsurance | 2,953 |  |  |  |  |  |  |  |  |
Reserves for loss and loss adjustment expenses, net of reinsurance | 1,452,830 |  |  |  |  |  |  |  |  |
Short-tail lines |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 8,042,131 |  |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 7,276,034 |  |  |  |  |  |  |  |  |
Reserves for loss and loss adjustment expenses before 2014, net of reinsurance | 5,171 |  |  |  |  |  |  |  |  |
Reserves for loss and loss adjustment expenses, net of reinsurance | 771,268 |  |  |  |  |  |  |  |  |
Casualty |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 3,391,253 |  |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 1,619,402 |  |  |  |  |  |  |  |  |
Reserves for loss and loss adjustment expenses before 2014, net of reinsurance | 402,281 |  |  |  |  |  |  |  |  |
Reserves for loss and loss adjustment expenses, net of reinsurance | 2,174,132 |  |  |  |  |  |  |  |  |
Monoline excess |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 622,374 |  |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 127,434 |  |  |  |  |  |  |  |  |
Reserves for loss and loss adjustment expenses before 2014, net of reinsurance | 576,491 |  |  |  |  |  |  |  |  |
Reserves for loss and loss adjustment expenses, net of reinsurance | 1,071,431 |  |  |  |  |  |  |  |  |
Property |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 1,361,346 |  |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 1,087,421 |  |  |  |  |  |  |  |  |
Reserves for loss and loss adjustment expenses before 2014, net of reinsurance | 1,472 |  |  |  |  |  |  |  |  |
Reserves for loss and loss adjustment expenses, net of reinsurance | 275,397 |  |  |  |  |  |  |  |  |
Accident Year 2014 | Other liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 863,342 | $ 863,636 | $ 862,440 | $ 863,890 | $ 868,639 | $ 862,568 | $ 849,657 | $ 845,254 | $ 847,308 | $ 846,005
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 810,687 | 782,462 | 759,003 | 729,573 | 679,351 | 593,577 | 479,657 | 337,870 | 190,637 | 78,811
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 28,447 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 28,000 |  |  |  |  |  |  |  |  |
Accident Year 2014 | Workers' compensation |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 589,283 | 598,977 | 602,000 | 600,194 | 604,030 | 615,435 | 617,242 | 627,767 | 637,307 | 639,436
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 553,739 | 547,894 | 538,914 | 531,475 | 521,141 | 503,915 | 471,235 | 412,611 | 319,743 | 148,405
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 12,555 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 57,000 |  |  |  |  |  |  |  |  |
Accident Year 2014 | Professional liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 256,527 | 254,514 | 255,527 | 256,157 | 257,205 | 238,388 | 242,903 | 258,874 | 245,854 | 252,473
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 243,397 | 238,277 | 235,581 | 226,323 | 214,915 | 198,176 | 175,230 | 137,931 | 83,246 | 19,318
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 10,067 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 7,000 |  |  |  |  |  |  |  |  |
Accident Year 2014 | Auto |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 408,743 | 408,816 | 407,435 | 408,304 | 412,757 | 412,929 | 415,490 | 417,539 | 385,214 | 363,882
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 407,212 | 405,817 | 405,061 | 404,067 | 401,368 | 393,428 | 364,768 | 327,548 | 237,622 | 155,553
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 291 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 47,000 |  |  |  |  |  |  |  |  |
Accident Year 2014 | Short-tail lines |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 656,326 | 656,931 | 658,600 | 660,388 | 657,968 | 657,637 | 656,704 | 658,437 | 701,133 | 697,102
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 652,449 | 652,379 | 652,054 | 651,560 | 649,068 | 641,861 | 626,751 | 608,396 | 590,511 | 369,514
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 1,483 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 30,000 |  |  |  |  |  |  |  |  |
Accident Year 2014 | Casualty |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 343,235 | 341,244 | 336,622 | 335,560 | 323,855 | 324,470 | 330,354 | 318,559 | 319,210 | 319,818
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 296,469 | 283,876 | 271,062 | 251,736 | 227,038 | 197,644 | 154,811 | 115,585 | 68,906 | 21,302
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 13,680 |  |  |  |  |  |  |  |  |
Accident Year 2014 | Monoline excess |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 32,185 | 35,707 | 40,652 | 42,618 | 42,541 | 41,671 | 45,758 | 49,478 | 57,558 | 63,465
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 14,632 | 13,491 | 11,938 | 11,154 | 7,595 | 5,808 | 4,175 | 3,354 | 1,729 | 358
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 3,400 |  |  |  |  |  |  |  |  |
Accident Year 2014 | Property |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 96,135 | 96,648 | 97,308 | 99,244 | 98,846 | 99,200 | 99,973 | 97,261 | 96,586 | 113,055
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 94,996 | 95,620 | 95,186 | 94,552 | 93,087 | 91,376 | 88,240 | 82,113 | 66,816 | $ 38,734
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 344 |  |  |  |  |  |  |  |  |
Accident Year 2015 | Other liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 1,018,418 | 1,011,753 | 982,145 | 975,534 | 965,497 | 963,237 | 960,136 | 985,529 | 949,853 |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 928,793 | 873,489 | 814,964 | 756,353 | 675,274 | 537,415 | 381,682 | 210,421 | 82,664 |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 42,923 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 28,000 |  |  |  |  |  |  |  |  |
Accident Year 2015 | Workers' compensation |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 603,732 | 612,687 | 617,478 | 620,741 | 626,432 | 641,169 | 650,997 | 690,525 | 712,800 |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 564,658 | 557,215 | 544,849 | 531,512 | 512,933 | 477,541 | 421,734 | 323,744 | 139,320 |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 18,013 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 58,000 |  |  |  |  |  |  |  |  |
Accident Year 2015 | Professional liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 286,320 | 286,950 | 282,806 | 282,452 | 291,157 | 275,604 | 274,233 | 257,634 | 259,122 |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 258,988 | 246,501 | 239,514 | 232,506 | 215,821 | 187,007 | 139,396 | 85,169 | 20,319 |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 13,275 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 8,000 |  |  |  |  |  |  |  |  |
Accident Year 2015 | Auto |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 428,339 | 428,898 | 427,079 | 429,950 | 431,514 | 430,503 | 422,344 | 416,251 | 389,529 |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 421,749 | 419,891 | 416,060 | 410,275 | 396,832 | 369,223 | 324,175 | 264,377 | 159,932 |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 1,013 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 53,000 |  |  |  |  |  |  |  |  |
Accident Year 2015 | Short-tail lines |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 714,974 | 710,266 | 709,937 | 711,665 | 713,225 | 721,082 | 722,556 | 725,927 | 737,494 |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 716,682 | 707,447 | 707,271 | 700,569 | 694,780 | 685,314 | 663,402 | 608,056 | 392,762 |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 2,044 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 32,000 |  |  |  |  |  |  |  |  |
Accident Year 2015 | Casualty |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 313,327 | 308,986 | 304,503 | 303,053 | 293,032 | 252,249 | 230,136 | 231,574 | 259,244 |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 266,497 | 250,504 | 233,281 | 204,981 | 178,280 | 141,073 | 91,016 | 48,371 | 17,876 |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 16,235 |  |  |  |  |  |  |  |  |
Accident Year 2015 | Monoline excess |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 27,590 | 30,104 | 36,774 | 39,781 | 39,682 | 45,115 | 50,099 | 57,897 | 69,977 |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 6,844 | 6,457 | 5,421 | 5,083 | 4,416 | 4,099 | 3,272 | 2,481 | 2,069 |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 4,664 |  |  |  |  |  |  |  |  |
Accident Year 2015 | Property |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 131,947 | 131,393 | 130,697 | 131,133 | 129,472 | 130,389 | 131,722 | 117,503 | 127,315 |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 128,947 | 128,037 | 126,895 | 125,494 | 122,630 | 118,615 | 109,053 | 89,120 | $ 53,435 |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 1,007 |  |  |  |  |  |  |  |  |
Accident Year 2016 | Other liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 1,134,162 | 1,092,036 | 1,060,478 | 1,044,563 | 1,030,490 | 1,019,067 | 1,010,016 | 1,017,074 |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 955,951 | 871,252 | 766,774 | 676,957 | 558,176 | 389,988 | 208,851 | 69,404 |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 80,989 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 28,000 |  |  |  |  |  |  |  |  |
Accident Year 2016 | Workers' compensation |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 641,549 | 654,385 | 657,972 | 651,278 | 660,520 | 684,700 | 696,339 | 702,716 |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 584,330 | 572,669 | 558,934 | 537,861 | 504,850 | 446,072 | 338,835 | 142,998 |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 19,823 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 58,000 |  |  |  |  |  |  |  |  |
Accident Year 2016 | Professional liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 449,678 | 463,625 | 468,154 | 438,761 | 401,569 | 360,778 | 324,043 | 310,140 |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 412,645 | 405,052 | 357,094 | 297,088 | 254,994 | 201,167 | 102,232 | 28,503 |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 15,850 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 9,000 |  |  |  |  |  |  |  |  |
Accident Year 2016 | Auto |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 442,164 | 440,412 | 438,616 | 438,917 | 442,122 | 441,051 | 429,762 | 430,132 |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 433,882 | 427,662 | 419,203 | 408,676 | 389,233 | 340,319 | 278,289 | 183,777 |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 2,410 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 52,000 |  |  |  |  |  |  |  |  |
Accident Year 2016 | Short-tail lines |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 752,960 | 752,541 | 753,926 | 751,510 | 757,010 | 762,449 | 775,358 | 771,829 |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 744,157 | 739,143 | 738,302 | 731,552 | 726,462 | 711,238 | 669,738 | 416,513 |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 3,288 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 34,000 |  |  |  |  |  |  |  |  |
Accident Year 2016 | Casualty |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 309,126 | 310,273 | 301,242 | 301,629 | 267,808 | 245,317 | 252,786 | 240,868 |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 241,884 | 224,739 | 205,052 | 171,465 | 140,104 | 100,074 | 61,710 | 19,884 |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 19,483 |  |  |  |  |  |  |  |  |
Accident Year 2016 | Monoline excess |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 53,304 | 61,432 | 65,222 | 65,485 | 64,957 | 71,404 | 70,281 | 72,657 |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 13,569 | 11,819 | 9,883 | 7,685 | 5,928 | 5,573 | 4,783 | 2,498 |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 6,192 |  |  |  |  |  |  |  |  |
Accident Year 2016 | Property |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 186,176 | 185,133 | 184,053 | 186,086 | 180,816 | 181,595 | 174,440 | 167,998 |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 184,208 | 182,300 | 177,961 | 175,867 | 168,433 | 157,341 | 133,478 | $ 78,887 |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 1,303 |  |  |  |  |  |  |  |  |
Accident Year 2017 | Other liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 1,267,359 | 1,249,086 | 1,178,596 | 1,138,821 | 1,121,979 | 1,099,566 | 1,065,837 |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 1,048,203 | 930,529 | 774,674 | 638,879 | 453,073 | 255,591 | 79,937 |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 95,118 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 28,000 |  |  |  |  |  |  |  |  |
Accident Year 2017 | Workers' compensation |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 675,871 | 682,153 | 683,880 | 673,216 | 689,622 | 733,505 | 762,093 |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 603,006 | 583,258 | 559,198 | 525,753 | 468,817 | 362,299 | 153,456 |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 22,933 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 58,000 |  |  |  |  |  |  |  |  |
Accident Year 2017 | Professional liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 401,661 | 393,054 | 384,107 | 377,209 | 338,526 | 332,317 | 333,255 |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 329,303 | 306,535 | 261,033 | 242,929 | 162,660 | 96,179 | 36,450 |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 45,095 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 10,000 |  |  |  |  |  |  |  |  |
Accident Year 2017 | Auto |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 445,263 | 444,483 | 440,004 | 434,186 | 430,205 | 428,420 | 430,445 |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 431,165 | 419,548 | 401,846 | 371,755 | 326,851 | 267,309 | 180,494 |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 3,148 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 47,000 |  |  |  |  |  |  |  |  |
Accident Year 2017 | Short-tail lines |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 746,406 | 747,710 | 746,475 | 746,878 | 747,521 | 753,274 | 752,865 |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 746,917 | 741,582 | 734,415 | 730,584 | 718,436 | 689,587 | 445,208 |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 4,267 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 42,000 |  |  |  |  |  |  |  |  |
Accident Year 2017 | Casualty |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 314,895 | 298,284 | 281,132 | 261,438 | 238,916 | 220,878 | 231,313 |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 207,378 | 174,745 | 147,049 | 123,404 | 69,190 | 40,013 | 16,457 |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 28,441 |  |  |  |  |  |  |  |  |
Accident Year 2017 | Monoline excess |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 55,713 | 62,647 | 66,795 | 71,025 | 70,749 | 80,508 | 76,701 |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 21,275 | 19,275 | 18,375 | 17,327 | 15,356 | 12,810 | 6,282 |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 9,442 |  |  |  |  |  |  |  |  |
Accident Year 2017 | Property |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 193,551 | 192,458 | 191,941 | 198,039 | 199,481 | 200,487 | 206,666 |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 188,497 | 185,895 | 182,680 | 179,799 | 171,736 | 141,390 | $ 72,114 |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 1,452 |  |  |  |  |  |  |  |  |
Accident Year 2018 | Other liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 1,299,691 | 1,232,803 | 1,156,233 | 1,121,429 | 1,131,672 | 1,104,011 |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 986,108 | 806,757 | 615,688 | 435,711 | 264,261 | 86,788 |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 141,108 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 28,000 |  |  |  |  |  |  |  |  |
Accident Year 2018 | Workers' compensation |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 715,018 | 721,170 | 724,056 | 715,055 | 724,697 | 778,964 |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 642,292 | 613,675 | 574,889 | 508,546 | 397,464 | 171,006 |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 27,179 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 56,000 |  |  |  |  |  |  |  |  |
Accident Year 2018 | Professional liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 397,593 | 382,239 | 359,493 | 333,413 | 322,297 | 335,128 |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 283,639 | 244,068 | 198,546 | 155,102 | 99,540 | 28,108 |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 81,991 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 10,000 |  |  |  |  |  |  |  |  |
Accident Year 2018 | Auto |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 530,374 | 521,794 | 494,442 | 479,085 | 462,657 | 442,701 |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 498,094 | 463,232 | 412,985 | 350,212 | 281,564 | 180,110 |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 6,234 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 45,000 |  |  |  |  |  |  |  |  |
Accident Year 2018 | Short-tail lines |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 741,264 | 742,212 | 744,467 | 746,183 | 748,859 | 759,748 |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 730,199 | 725,128 | 725,027 | 708,101 | 661,607 | 414,833 |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 7,835 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 48,000 |  |  |  |  |  |  |  |  |
Accident Year 2018 | Casualty |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 292,927 | 261,004 | 246,861 | 230,817 | 210,492 | 221,393 |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 182,326 | 141,309 | 109,290 | 77,371 | 40,884 | 11,056 |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 37,287 |  |  |  |  |  |  |  |  |
Accident Year 2018 | Monoline excess |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 50,744 | 57,847 | 66,180 | 71,448 | 72,505 | 77,820 |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 13,583 | 12,414 | 10,359 | 9,368 | 8,230 | 6,141 |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 12,964 |  |  |  |  |  |  |  |  |
Accident Year 2018 | Property |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 101,498 | 103,015 | 105,165 | 103,192 | 112,133 | 108,348 |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 96,262 | 94,931 | 87,789 | 82,327 | 65,071 | $ 33,972 |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 1,898 |  |  |  |  |  |  |  |  |
Accident Year 2019 | Other liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 1,371,217 | 1,294,768 | 1,237,950 | 1,237,516 | 1,240,667 |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 909,617 | 704,851 | 471,186 | 275,315 | 88,173 |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 205,380 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 29,000 |  |  |  |  |  |  |  |  |
Accident Year 2019 | Workers' compensation |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 722,456 | 734,034 | 732,762 | 721,018 | 784,281 |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 618,324 | 581,003 | 515,914 | 397,376 | 184,715 |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 39,081 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 54,000 |  |  |  |  |  |  |  |  |
Accident Year 2019 | Professional liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 362,983 | 354,121 | 345,548 | 332,426 | 336,397 |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 235,124 | 200,259 | 147,767 | 97,302 | 31,635 |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 89,944 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 11,000 |  |  |  |  |  |  |  |  |
Accident Year 2019 | Auto |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 548,688 | 530,967 | 504,901 | 488,379 | 483,120 |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 495,111 | 440,449 | 374,545 | 290,194 | 185,289 |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 11,878 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 45,000 |  |  |  |  |  |  |  |  |
Accident Year 2019 | Short-tail lines |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 684,707 | 684,606 | 690,928 | 701,168 | 721,072 |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 665,789 | 657,699 | 645,251 | 615,748 | 404,870 |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 14,592 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 43,000 |  |  |  |  |  |  |  |  |
Accident Year 2019 | Casualty |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 272,393 | 240,879 | 239,206 | 230,620 | 236,517 |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 142,501 | 94,735 | 63,945 | 39,035 | 14,544 |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 52,998 |  |  |  |  |  |  |  |  |
Accident Year 2019 | Monoline excess |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 66,071 | 73,978 | 76,242 | 77,482 | 78,929 |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 18,836 | 15,436 | 12,728 | 10,884 | 6,241 |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 12,977 |  |  |  |  |  |  |  |  |
Accident Year 2019 | Property |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 81,157 | 81,192 | 82,036 | 77,255 | 103,316 |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 73,234 | 71,264 | 68,693 | 54,709 | $ 23,129 |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 2,479 |  |  |  |  |  |  |  |  |
Accident Year 2020 | Other liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 1,167,753 | 1,158,966 | 1,212,875 | 1,339,702 |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 621,085 | 423,186 | 224,991 | 72,203 |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 317,212 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 23,000 |  |  |  |  |  |  |  |  |
Accident Year 2020 | Workers' compensation |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 668,222 | 704,008 | 716,430 | 725,245 |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 548,585 | 485,203 | 380,454 | 172,478 |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 36,045 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 42,000 |  |  |  |  |  |  |  |  |
Accident Year 2020 | Professional liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 313,386 | 337,796 | 375,559 | 394,304 |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 169,000 | 128,869 | 80,180 | 27,996 |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 100,150 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 11,000 |  |  |  |  |  |  |  |  |
Accident Year 2020 | Auto |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 469,184 | 442,165 | 428,761 | 523,739 |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 374,990 | 308,452 | 228,358 | 142,816 |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 16,227 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 30,000 |  |  |  |  |  |  |  |  |
Accident Year 2020 | Short-tail lines |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 926,379 | 922,258 | 904,545 | 900,816 |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 900,682 | 845,590 | 784,553 | 460,351 |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 7,624 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 38,000 |  |  |  |  |  |  |  |  |
Accident Year 2020 | Casualty |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 313,904 | 290,037 | 293,574 | 299,888 |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 137,043 | 81,710 | 49,637 | 20,746 |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 103,742 |  |  |  |  |  |  |  |  |
Accident Year 2020 | Monoline excess |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 72,376 | 80,452 | 83,468 | 84,354 |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 12,869 | 10,471 | 8,699 | 4,869 |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 26,582 |  |  |  |  |  |  |  |  |
Accident Year 2020 | Property |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 121,417 | 116,786 | 117,885 | 114,645 |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 95,643 | 86,885 | 65,563 | $ 26,606 |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 4,291 |  |  |  |  |  |  |  |  |
Accident Year 2021 | Other liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 1,347,336 | 1,390,800 | 1,534,634 |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 492,271 | 267,564 | 76,568 |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 537,640 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 25,000 |  |  |  |  |  |  |  |  |
Accident Year 2021 | Workers' compensation |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 667,517 | 701,703 | 742,687 |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 490,648 | 384,867 | 172,729 |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 67,127 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 46,000 |  |  |  |  |  |  |  |  |
Accident Year 2021 | Professional liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 446,596 | 471,456 | 525,389 |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 153,063 | 85,886 | 28,542 |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 215,820 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 11,000 |  |  |  |  |  |  |  |  |
Accident Year 2021 | Auto |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 632,918 | 596,810 | 614,422 |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 429,419 | 319,941 | 180,860 |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 54,629 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 38,000 |  |  |  |  |  |  |  |  |
Accident Year 2021 | Short-tail lines |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 815,228 | 832,240 | 828,347 |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 754,448 | 698,030 | 405,461 |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 24,478 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 36,000 |  |  |  |  |  |  |  |  |
Accident Year 2021 | Casualty |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 344,272 | 347,054 | 360,399 |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 89,076 | 43,791 | 10,910 |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 190,749 |  |  |  |  |  |  |  |  |
Accident Year 2021 | Monoline excess |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 77,220 | 87,980 | 98,110 |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 8,872 | 6,026 | 4,586 |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 31,581 |  |  |  |  |  |  |  |  |
Accident Year 2021 | Property |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 144,429 | 146,726 | 133,989 |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 109,179 | 71,800 | $ 15,245 |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 13,709 |  |  |  |  |  |  |  |  |
Accident Year 2022 | Other liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 1,830,125 | 1,823,703 |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 356,621 | 93,477 |  |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 1,116,619 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 25,000 |  |  |  |  |  |  |  |  |
Accident Year 2022 | Workers' compensation |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 745,218 | 772,620 |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 408,929 | 180,982 |  |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 153,476 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 46,000 |  |  |  |  |  |  |  |  |
Accident Year 2022 | Professional liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 586,327 | 649,725 |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 90,594 | 33,417 |  |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 405,848 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 11,000 |  |  |  |  |  |  |  |  |
Accident Year 2022 | Auto |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 825,359 | 792,553 |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 428,621 | 253,206 |  |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 192,025 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 44,000 |  |  |  |  |  |  |  |  |
Accident Year 2022 | Short-tail lines |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 928,562 | 945,041 |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 799,125 | 472,020 |  |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 54,776 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 36,000 |  |  |  |  |  |  |  |  |
Accident Year 2022 | Casualty |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 437,358 | 447,231 |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 45,625 | 11,574 |  |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 325,597 |  |  |  |  |  |  |  |  |
Accident Year 2022 | Monoline excess |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 76,725 | 98,923 |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 10,564 | 5,898 |  |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 35,307 |  |  |  |  |  |  |  |  |
Accident Year 2022 | Property |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 167,351 | 167,223 |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 91,718 | $ 25,515 |  |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 30,362 |  |  |  |  |  |  |  |  |
Accident Year 2023 | Other liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 2,120,365 |  |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 92,758 |  |  |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 1,815,051 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 19,000 |  |  |  |  |  |  |  |  |
Accident Year 2023 | Workers' compensation |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 784,906 |  |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 195,204 |  |  |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 352,511 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 43,000 |  |  |  |  |  |  |  |  |
Accident Year 2023 | Professional liability |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 648,231 |  |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 41,064 |  |  |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 509,380 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 12,000 |  |  |  |  |  |  |  |  |
Accident Year 2023 | Auto |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 916,722 |  |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 277,634 |  |  |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 444,715 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 40,000 |  |  |  |  |  |  |  |  |
Accident Year 2023 | Short-tail lines |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 1,075,325 |  |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 565,586 |  |  |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 286,870 |  |  |  |  |  |  |  |  |
Short-duration insurance contract, cumulative number of reported claims | claim | 27,000 |  |  |  |  |  |  |  |  |
Accident Year 2023 | Casualty |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | $ 449,816 |  |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 10,603 |  |  |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 396,340 |  |  |  |  |  |  |  |  |
Accident Year 2023 | Monoline excess |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 110,446 |  |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 6,390 |  |  |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | 73,881 |  |  |  |  |  |  |  |  |
Accident Year 2023 | Property |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Loss and loss expenses incurred, net of reinsurance | 137,685 |  |  |  |  |  |  |  |  |
Cumulative paid claims and claim adjustment expenses, net of reinsurance | 24,737 |  |  |  |  |  |  |  |  |
Short-duration insurance contracts, incurred but not reported (IBNR) claims liability, net | $ 60,458 |  |  |  |  |  |  |  |  |

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