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Loss and Loss Adjustment Expenses (Tables) | 12 Months Ended
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Dec. 31, 2020
Insurance [Abstract] |
Summary of Development Tables of Incurred and Paid Losses and Allocated Loss Adjustment Expenses Net of Reinsurance |
|  | Incurred Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance |  |  | As of |
|  | For the Years Ended December 31, |  |  | December 31, 2020 |
|  | (Dollars in thousands) |  |  | Total IBNR |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | Plus |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | Expected |  |  | Cumulative |
|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | Development |  |  | Number of |
Accident |  | Unaudited (1) |  |  |  |  |  |  | on Reported |  |  | Claims |
Year |  | 2011 |  | 2012 |  | 2013 |  | 2014 |  | 2015 |  | 2016 |  | 2017 |  | 2018 |  | 2019 |  |  | 2020 |  |  | Claims |  |  | Reported |
2011 |  | $ | 196,384 |  | $ | 199,522 |  | $ | 199,163 |  | $ | 198,213 |  | $ | 195,262 |  | $ | 192,988 |  | $ | 191,126 |  | $ | 189,327 |  | $ | 188,226 |  |  | $ | 188,264 |  |  | $ | 5,198 |  |  |  | 6,044 |
2012 |  |  | — |  |  | 222,549 |  |  | 222,075 |  |  | 212,738 |  |  | 193,515 |  |  | 184,460 |  |  | 182,859 |  |  | 180,387 |  |  | 178,586 |  |  |  | 177,547 |  |  |  | 6,419 |  |  |  | 5,749 |
2013 |  |  | — |  |  | — |  |  | 241,810 |  |  | 241,811 |  |  | 233,656 |  |  | 220,457 |  |  | 214,701 |  |  | 210,588 |  |  | 209,184 |  |  |  | 207,304 |  |  |  | 7,762 |  |  |  | 5,766 |
2014 |  |  | — |  |  | — |  |  | — |  |  | 268,846 |  |  | 268,846 |  |  | 249,097 |  |  | 235,058 |  |  | 226,933 |  |  | 218,386 |  |  |  | 212,417 |  |  |  | 5,468 |  |  |  | 5,839 |
2015 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 262,573 |  |  | 262,573 |  |  | 252,514 |  |  | 235,471 |  |  | 220,965 |  |  |  | 211,758 |  |  |  | 6,717 |  |  |  | 5,516 |
2016 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 250,491 |  |  | 250,491 |  |  | 241,406 |  |  | 218,005 |  |  |  | 209,214 |  |  |  | 6,843 |  |  |  | 5,393 |
2017 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 244,094 |  |  | 244,098 |  |  | 234,587 |  |  |  | 220,096 |  |  |  | 8,066 |  |  |  | 5,211 |
2018 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 250,487 |  |  | 250,487 |  |  |  | 235,641 |  |  |  | 16,057 |  |  |  | 5,467 |
2019 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 241,344 |  |  |  | 241,344 |  |  |  | 16,609 |  |  |  | 5,199 |
2020 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  |  | 220,710 |  |  |  | 8,491 |  |  |  | 4,170 |
|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | Total |  |  | $ | 2,124,295 |  |  | $ | 87,630 |  |  |  |  |
|  | Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance |  |  |  |  |
|  | For the Years Ended December 31, |  |  |  |  |
|  | (Dollars in thousands) |  |  |  |  |
Accident |  | Unaudited (1) |  |  |  |  |  |  | Claim |
Year |  | 2011 |  | 2012 |  | 2013 |  | 2014 |  | 2015 |  | 2016 |  | 2017 |  | 2018 |  | 2019 |  |  | 2020 |  |  | Frequency (2) |
2011 |  | $ | 53,329 |  | $ | 111,029 |  | $ | 140,831 |  | $ | 153,968 |  | $ | 161,639 |  | $ | 165,967 |  | $ | 167,757 |  | $ | 169,994 |  | $ | 170,785 |  |  | $ | 171,583 |  |  |  | 22.82 |
2012 |  |  | — |  |  | 50,579 |  |  | 107,467 |  |  | 133,658 |  |  | 149,161 |  |  | 154,553 |  |  | 157,207 |  |  | 159,807 |  |  | 161,014 |  |  |  | 162,588 |  |  |  | 18.73 |
2013 |  |  | — |  |  | — |  |  | 51,396 |  |  | 119,507 |  |  | 150,304 |  |  | 165,994 |  |  | 172,479 |  |  | 177,724 |  |  | 180,614 |  |  |  | 182,465 |  |  |  | 16.55 |
2014 |  |  | — |  |  | — |  |  | — |  |  | 53,060 |  |  | 119,820 |  |  | 153,320 |  |  | 169,736 |  |  | 180,683 |  |  | 186,129 |  |  |  | 191,394 |  |  |  | 14.99 |
2015 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 54,141 |  |  | 121,599 |  |  | 151,818 |  |  | 170,461 |  |  | 182,053 |  |  |  | 185,657 |  |  |  | 14.25 |
2016 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 52,238 |  |  | 115,713 |  |  | 143,016 |  |  | 156,861 |  |  |  | 166,887 |  |  |  | 14.23 |
2017 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 56,951 |  |  | 122,552 |  |  | 151,427 |  |  |  | 166,448 |  |  |  | 14.68 |
2018 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 62,061 |  |  | 126,057 |  |  |  | 152,328 |  |  |  | 15.20 |
2019 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | 58,883 |  |  |  | 120,512 |  |  |  | 15.21 |
2020 |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  | — |  |  |  | 50,113 |  |  |  | 13.25 |
|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | Total |  |  |  | 1,549,975 |  |  |  |  |
All outstanding liabilities before 2011, net of reinsurance |  |  |  | 80,533 |  |  |  |  |
Liabilities for loss and loss adjustment expenses, net of reinsurance |  |  |  | 654,854 |  |  |  |  |
(1) Data presented for these calendar years is required supplementary information, which is unaudited. |
(2) Frequency, as calculated above, refers to reported claims divided by gross premium earned. |
Summary of Average Annual Percentage Payout of Incurred Losses by Age Net of Reinsurance for Worker's Compensation and General Liability | The average annual percentage payout of incurred losses by age, net of reinsurance, for workers’ compensation and general liability as of December 31, 2020 is summarized below. Since workers’ compensation has long payout periods, the table below shows less than 100% in the years disclosed. This is required supplementary information, which is unaudited.
Average Annual Percentage Payout of Incurred Losses by Age, Net of Reinsurance (Unaudited) |
Year 1 |  |  | Year 2 |  | Year 3 |  | Year 4 |  | Year 5 |  | Year 6 |  | Year 7 |  | Year 8 |  | Year 9 |  | Year 10 |
25.6% |  |  | 30.2% |  | 14.1% |  | 7.6% |  | 4.3% |  | 2.1% |  | 1.6% |  | 0.9% |  | 0.7% |  | 0.4% |
Reconciliation of Beginning and Ending Reserve Balances, Net of Related Amounts Recoverable from Reinsurers | The following table provides a reconciliation of the beginning and ending reserve balances, net of related amounts recoverable from reinsurers, for 2020, 2019 and 2018:
|  | Year Ended December 31, |
|  | 2020 |  |  | 2019 |  |  | 2018 |
|  | (in thousands) |
Balance, beginning of period |  | $ | 772,887 |  |  | $ | 798,409 |  |  | $ | 771,845 |
Less amounts recoverable from reinsurers on unpaid loss and loss adjustment expenses |  |  | 95,343 |  |  |  | 107,216 |  |  |  | 84,889 |
Net balance, beginning of period |  |  | 677,544 |  |  |  | 691,193 |  |  |  | 686,956 |
Add incurred related to: |  |  |  |  |  |  |  |  |  |  |  |
Current accident year |  |  | 220,710 |  |  |  | 241,344 |  |  |  | 250,487 |
Prior accident years |  |  | (63,484 | ) |  |  | (65,002 | ) |  |  | (45,596 | )
Total incurred |  |  | 157,226 |  |  |  | 176,342 |  |  |  | 204,891 |
Less paid related to: |  |  |  |  |  |  |  |  |  |  |  |
Current accident year |  |  | 50,113 |  |  |  | 58,883 |  |  |  | 62,061 |
Prior accident years |  |  | 129,803 |  |  |  | 131,108 |  |  |  | 138,593 |
Total paid |  |  | 179,916 |  |  |  | 189,991 |  |  |  | 200,654 |
Net balance, end of period |  |  | 654,854 |  |  |  | 677,544 |  |  |  | 691,193 |
Add amounts recoverable from reinsurers on unpaid loss and loss adjustment expenses |  |  | 105,707 |  |  |  | 95,343 |  |  |  | 107,216 |
Balance, end of period |  | $ | 760,561 |  |  | $ | 772,887 |  |  | $ | 798,409 |
Summary Exposures to Various Asbestos Related Claims | The following table details our exposures to various asbestos related claims:
|  | Year Ended December 31, |
|  | 2020 |  |  | 2019 |  |  | 2018 |
|  | (in thousands) |
Reserves for loss and LAE at beginning of year |  | $ | 1,323 |  |  | $ | 1,555 |  |  | $ | 1,748 |
Incurred losses and LAE during the current year |  |  | (936 | ) |  |  | (183 | ) |  |  | 108 |
Loss and LAE payments |  |  | (69 | ) |  |  | (49 | ) |  |  | (301 | )
Reserves for loss and LAE at end of year |  | $ | 318 |  |  | $ | 1,323 |  |  | $ | 1,555 |

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