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Reserve for Loss and Loss Expense (Claims Development) (Details) $ in Thousands | 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 ($) | Dec. 31, 2013 USD ($) | Dec. 31, 2012 USD ($) | Dec. 31, 2011 USD ($)
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Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | $ 12,185,164 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 8,973,347 |  |  |  |  |  |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 3,576,212 |  |  |  |  |  |  |  |  |
Reserve for loss and loss expense | 4,260,355 | $ 4,067,163 |  |  |  |  |  |  |  |
Short-Duration Insurance Contracts, Accident Years Prior to 2011 [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 364,395 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2011 [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 1,009,162 | 1,013,175 | $ 1,013,115 | $ 1,019,351 | $ 1,023,726 | $ 1,033,518 | $ 1,056,107 | $ 1,062,233 | $ 1,061,667 | $ 1,042,576
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 36,641 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 105,039 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 957,391 | 950,836 | 940,626 | 924,111 | 901,801 | 852,202 | 782,655 | 692,730 | 585,867 | 391,944
Short-duration Insurance Contracts, Accident Year 2012 [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 962,091 | 968,536 | 973,411 | 973,644 | 973,089 | 998,028 | 1,020,655 | 1,071,290 | 1,065,437 |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 41,426 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 104,343 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 905,816 | 898,269 | 879,372 | 856,195 | 810,135 | 743,742 | 651,544 | 555,819 | 378,067 |
Short-duration Insurance Contracts, Accident Year 2013 [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 973,739 | 984,858 | 987,763 | 1,002,316 | 1,021,007 | 1,047,230 | 1,062,045 | 1,044,142 |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 57,866 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 91,539 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 904,825 | 891,841 | 872,331 | 833,823 | 748,758 | 644,475 | 518,872 | 335,956 |  |
Short-duration Insurance Contracts, Accident Year 2014 [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 1,089,529 | 1,100,208 | 1,104,218 | 1,124,014 | 1,146,990 | 1,133,798 | 1,107,513 |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 60,028 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 95,366 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 1,002,157 | 981,868 | 936,425 | 855,959 | 736,154 | 614,075 | 405,898 |  |  |
Short-duration Insurance Contracts, Accident Year 2015 [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 1,108,860 | 1,119,441 | 1,138,313 | 1,144,830 | 1,130,513 | 1,114,081 |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 77,855 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 94,594 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 967,857 | 929,222 | 845,868 | 725,385 | 581,203 | 376,641 |  |  |  |
Short-duration Insurance Contracts, Accident Year 2016 [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 1,180,829 | 1,199,734 | 1,227,142 | 1,203,634 | 1,188,608 |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 126,935 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 95,203 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 983,852 | 892,390 | 764,331 | 617,958 | 387,272 |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2017 [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 1,288,526 | 1,313,585 | 1,313,372 | 1,270,110 |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 206,627 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 98,918 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 954,792 | 829,134 | 678,453 | 433,440 |  |  |  |  |  |
Short-duration Insurance Contracts, Accident Year 2018 [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 1,457,415 | 1,461,603 | 1,413,800 |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 342,256 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 105,772 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 942,893 | 779,466 | 511,271 |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2019 [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 1,523,041 | 1,483,945 |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 539,113 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 101,631 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 781,462 | 510,091 |  |  |  |  |  |  |  |
Short-Duration Insurance Contract, Accident Year 2020 |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 1,591,972 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 820,762 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 85,549 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 572,302 |  |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 2,633,440 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 1,347,996 |  |  |  |  |  |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 1,380,902 |  |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Workers Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 1,716,956 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 1,132,576 |  |  |  |  |  |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 828,146 |  |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Commercial Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 2,781,151 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 2,154,487 |  |  |  |  |  |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 630,512 |  |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Business Owners' Policies [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 546,289 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 462,643 |  |  |  |  |  |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 91,419 |  |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Commercial Property [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 1,466,423 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 1,392,416 |  |  |  |  |  |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 74,182 |  |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-Duration Insurance Contracts, Accident Years Prior to 2011 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 95,458 |  |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-Duration Insurance Contracts, Accident Years Prior to 2011 [Member] | Workers Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 243,766 |  |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-Duration Insurance Contracts, Accident Years Prior to 2011 [Member] | Commercial Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 3,848 |  |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-Duration Insurance Contracts, Accident Years Prior to 2011 [Member] | Business Owners' Policies [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 7,773 |  |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-Duration Insurance Contracts, Accident Years Prior to 2011 [Member] | Commercial Property [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 175 |  |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2011 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 209,846 | 213,485 | 211,500 | 212,011 | 211,196 | 217,256 | 230,785 | 239,480 | 228,720 | 227,769
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 13,501 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 11,691 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 190,650 | 187,276 | 181,856 | 170,525 | 159,768 | 135,377 | 102,978 | 73,643 | 42,692 | 13,924
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2011 [Member] | Workers Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 191,875 | 192,863 | 194,821 | 200,674 | 205,708 | 210,591 | 215,114 | 214,743 | 218,973 | 205,238
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 21,900 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 11,863 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 163,554 | 161,696 | 158,535 | 154,320 | 149,269 | 139,232 | 134,646 | 118,847 | 90,836 | 42,941
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2011 [Member] | Commercial Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 172,684 | 173,401 | 173,507 | 174,514 | 174,882 | 172,617 | 178,421 | 182,325 | 183,044 | 174,006
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 205 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 25,651 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 172,413 | 172,365 | 170,913 | 170,000 | 166,082 | 157,291 | 142,507 | 121,576 | 99,196 | 69,849
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2011 [Member] | Business Owners' Policies [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 58,697 | 58,948 | 58,735 | 58,456 | 58,966 | 59,256 | 58,242 | 51,047 | 57,083 | 54,469
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 516 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 4,961 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 57,385 | 57,380 | 57,365 | 57,045 | 55,856 | 52,114 | 46,444 | 41,011 | 37,362 | 27,884
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2011 [Member] | Commercial Property [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 130,994 | 131,002 | 131,009 | 131,049 | 131,113 | 131,353 | 131,282 | 130,942 | 131,667 | 136,954
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 9 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 9,038 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 131,083 | 131,092 | 131,100 | 131,089 | 131,115 | 131,060 | 130,681 | 129,579 | 127,580 | 94,538
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 178,285 | 182,085 | 180,659 | 175,268 | 175,305 | 194,144 | 215,083 | 245,561 | 238,979 |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 15,055 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 10,034 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 158,397 | 156,186 | 144,451 | 130,866 | 109,448 | 89,008 | 56,580 | 35,241 | 13,030 |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member] | Workers Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 177,658 | 178,774 | 183,314 | 187,359 | 188,596 | 195,197 | 199,360 | 208,036 | 203,864 |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 23,181 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 11,624 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 148,750 | 146,739 | 143,281 | 139,477 | 132,052 | 122,755 | 108,211 | 86,909 | 40,911 |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member] | Commercial Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 184,477 | 185,357 | 184,633 | 186,128 | 184,367 | 184,289 | 183,527 | 191,947 | 179,551 |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 811 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 24,295 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 183,098 | 181,353 | 179,501 | 176,656 | 168,114 | 148,669 | 127,235 | 105,371 | 73,316 |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member] | Business Owners' Policies [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 43,444 | 43,717 | 43,418 | 43,747 | 44,077 | 44,172 | 46,303 | 48,029 | 54,342 |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 117 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 5,545 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 42,075 | 41,356 | 41,326 | 40,627 | 38,766 | 37,215 | 35,089 | 31,833 | 22,199 |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member] | Commercial Property [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 117,200 | 117,220 | 117,225 | 117,170 | 117,102 | 116,658 | 115,375 | 114,224 | 118,464 |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 6 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 8,517 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 116,673 | 116,674 | 116,671 | 116,625 | 116,291 | 114,699 | 111,503 | 108,834 | 81,528 |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 195,697 | 202,697 | 203,831 | 210,785 | 225,709 | 239,776 | 251,421 | 250,609 |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 19,110 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 10,397 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 169,847 | 163,764 | 153,628 | 139,114 | 104,587 | 72,127 | 35,113 | 12,789 |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member] | Workers Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 157,645 | 159,767 | 162,787 | 166,662 | 173,160 | 187,658 | 194,318 | 199,794 |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 23,321 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 11,382 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 129,224 | 126,822 | 124,130 | 118,669 | 109,739 | 96,376 | 74,568 | 36,829 |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member] | Commercial Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 208,040 | 209,602 | 207,975 | 210,410 | 207,994 | 209,197 | 205,282 | 188,289 |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 1,694 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 25,886 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 205,064 | 202,622 | 200,750 | 189,626 | 169,850 | 140,015 | 109,893 | 76,469 |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member] | Business Owners' Policies [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 39,358 | 39,699 | 39,709 | 41,369 | 40,624 | 41,005 | 42,618 | 49,617 |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 554 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 3,483 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 39,212 | 39,085 | 38,464 | 37,993 | 34,760 | 30,845 | 26,592 | 17,412 |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member] | Commercial Property [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 90,486 | 90,218 | 90,278 | 90,436 | 90,005 | 90,103 | 90,639 | 88,101 |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 11 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 5,715 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 90,917 | 90,646 | 90,696 | 90,840 | 90,350 | 90,446 | 87,874 | 60,244 |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2014 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 229,679 | 237,125 | 234,082 | 239,333 | 257,132 | 249,946 | 244,312 |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 29,018 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 10,652 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 187,352 | 179,192 | 154,957 | 121,969 | 79,972 | 46,825 | 14,901 |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2014 [Member] | Workers Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 159,604 | 160,646 | 164,420 | 172,515 | 182,579 | 187,065 | 199,346 |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 25,582 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 10,495 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 127,858 | 124,077 | 119,392 | 113,626 | 100,876 | 78,944 | 35,924 |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2014 [Member] | Commercial Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 216,461 | 217,334 | 218,172 | 219,925 | 216,824 | 212,725 | 200,534 |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 2,096 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 27,896 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 212,481 | 209,655 | 202,821 | 180,701 | 148,884 | 117,169 | 80,810 |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2014 [Member] | Business Owners' Policies [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 57,302 | 58,093 | 58,517 | 59,806 | 62,548 | 60,949 | 55,962 |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 616 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 4,066 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 55,708 | 55,458 | 52,940 | 49,460 | 44,911 | 40,584 | 28,914 |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2014 [Member] | Commercial Property [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 136,237 | 136,212 | 138,155 | 138,751 | 136,820 | 136,249 | 141,192 |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 13 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 6,516 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 135,928 | 136,008 | 137,418 | 137,883 | 136,634 | 132,909 | 101,131 |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 214,176 | 219,204 | 233,249 | 246,990 | 245,710 | 254,720 |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 38,182 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 10,537 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 157,071 | 144,216 | 116,804 | 78,668 | 39,978 | 14,665 |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member] | Workers Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 172,572 | 176,242 | 179,642 | 183,604 | 194,639 | 193,729 |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 22,368 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 10,551 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 124,046 | 120,097 | 112,601 | 98,195 | 77,320 | 33,857 |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member] | Commercial Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 261,386 | 260,565 | 259,495 | 253,074 | 240,958 | 220,994 |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 2,729 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 29,590 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 249,905 | 238,142 | 211,515 | 175,866 | 132,260 | 91,347 |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member] | Business Owners' Policies [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 52,325 | 54,454 | 55,925 | 57,245 | 53,768 | 52,871 |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 1,178 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 3,963 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 49,839 | 49,073 | 46,571 | 42,710 | 36,014 | 24,189 |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member] | Commercial Property [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 112,582 | 112,496 | 111,566 | 111,750 | 109,513 | 110,270 |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 24 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 6,406 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 112,117 | 110,969 | 110,994 | 109,829 | 106,182 | 79,048 |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 252,733 | 263,245 | 277,986 | 272,048 | 277,214 |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 61,329 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 10,753 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 164,136 | 133,757 | 89,431 | 46,549 | 15,684 |  |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member] | Workers Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 156,540 | 166,009 | 176,248 | 184,946 | 196,774 |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 29,220 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 10,582 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 115,159 | 109,166 | 98,037 | 78,531 | 34,525 |  |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member] | Commercial Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 290,359 | 285,304 | 285,302 | 274,367 | 255,187 |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 8,469 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 31,465 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 264,858 | 233,939 | 200,701 | 155,720 | 106,022 |  |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member] | Business Owners' Policies [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 53,367 | 53,835 | 54,993 | 53,792 | 52,335 |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 1,877 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 3,847 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 48,786 | 45,308 | 39,973 | 36,848 | 24,655 |  |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member] | Commercial Property [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 123,567 | 124,487 | 125,937 | 126,185 | 121,927 |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 60 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 6,741 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 123,601 | 123,828 | 122,930 | 118,789 | 83,966 |  |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 289,883 | 301,384 | 293,128 | 293,747 |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 114,160 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 11,096 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 131,980 | 92,355 | 49,470 | 17,366 |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Workers Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 162,672 | 175,853 | 184,306 | 195,202 |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 34,474 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 10,808 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 110,645 | 100,645 | 82,216 | 40,375 |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Commercial Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 322,197 | 324,291 | 329,389 | 301,274 |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 22,447 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 32,775 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 262,349 | 220,422 | 178,823 | 117,287 |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Business Owners' Policies [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 48,067 | 51,524 | 48,698 | 46,624 |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 5,981 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 3,885 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 40,359 | 36,950 | 31,337 | 21,865 |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Commercial Property [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 153,664 | 149,044 | 149,106 | 138,773 |  |  |  |  |  |
Short-duration Insurance, Contracts Incurred But Not Reported (IBNR) Claims Liability, Net | $ (289) |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 6,900 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 152,018 | 148,589 | 142,338 | 99,047 |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2018 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 345,224 | 336,326 | 317,934 |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 182,931 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 11,350 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 108,421 | 60,784 | 19,531 |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2018 [Member] | Workers Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 181,151 | 193,818 | 193,894 |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 48,883 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 11,111 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 105,903 | 84,780 | 41,122 |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2018 [Member] | Commercial Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 345,547 | 352,487 | 347,908 |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 47,298 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 35,418 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 243,713 | 193,788 | 134,867 |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2018 [Member] | Business Owners' Policies [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 62,427 | 57,202 | 55,024 |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 12,432 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 4,229 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 44,316 | 39,791 | 29,995 |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-duration Insurance Contracts, Accident Year 2018 [Member] | Commercial Property [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 192,558 | 190,834 | 183,177 |  |  |  |  |  |  |
Short-duration Insurance, Contracts Incurred But Not Reported (IBNR) Claims Liability, Net | $ (841) |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 8,280 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 192,698 | 184,813 | 135,416 |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2019 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 356,363 | 347,150 |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 248,289 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 10,531 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 58,284 | 18,097 |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2019 [Member] | Workers Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 188,596 | 188,625 |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 69,909 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 10,267 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 77,878 | 37,826 |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2019 [Member] | Commercial Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 398,346 | 385,212 |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 111,327 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 35,703 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 221,590 | 149,538 |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2019 [Member] | Business Owners' Policies [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 59,466 | 53,531 |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 12,872 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 3,541 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 41,587 | 27,718 |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2019 [Member] | Commercial Property [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 177,075 | 173,826 |  |  |  |  |  |  |  |
Short-duration Insurance, Contracts Incurred But Not Reported (IBNR) Claims Liability, Net | $ (738) |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 7,262 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 172,768 | 130,891 |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2020 | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 361,554 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 311,657 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 6,990 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 21,858 |  |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2020 | Workers Compensation [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 168,643 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 97,510 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 7,017 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 29,559 |  |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2020 | Commercial Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 381,654 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 195,279 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 28,366 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 139,016 |  |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2020 | Business Owners' Policies [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 71,836 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 17,392 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 5,019 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 43,376 |  |  |  |  |  |  |  |  |
Standard Commercial Lines [Member] | Short-Duration Insurance Contract, Accident Year 2020 | Commercial Property [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 232,060 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 37,050 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 9,494 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 164,613 |  |  |  |  |  |  |  |  |
Standard Personal Lines | Personal Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 1,063,316 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 975,981 |  |  |  |  |  |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 94,237 |  |  |  |  |  |  |  |  |
Standard Personal Lines | Homeowners [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 794,625 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 755,451 |  |  |  |  |  |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 44,159 |  |  |  |  |  |  |  |  |
Standard Personal Lines | Short-Duration Insurance Contracts, Accident Years Prior to 2011 [Member] | Personal Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 6,902 |  |  |  |  |  |  |  |  |
Standard Personal Lines | Short-Duration Insurance Contracts, Accident Years Prior to 2011 [Member] | Homeowners [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 4,985 |  |  |  |  |  |  |  |  |
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2011 [Member] | Personal Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 114,038 | 114,056 | 113,921 | 113,988 | 113,830 | 114,241 | 112,993 | 113,686 | 116,164 | 113,232
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 31 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 22,700 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 113,996 | 113,856 | 113,664 | 113,551 | 112,732 | 111,085 | 105,068 | 93,878 | 82,102 | 61,323
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2011 [Member] | Homeowners [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 94,524 | 94,572 | 94,587 | 94,378 | 94,183 | 94,543 | 94,167 | 97,761 | 98,211 | 103,804
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 37 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 15,111 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 94,452 | 94,458 | 94,412 | 94,007 | 93,720 | 93,312 | 92,185 | 91,718 | 89,963 | 71,668
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2012 [Member] | Personal Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 109,634 | 109,701 | 109,795 | 110,300 | 110,294 | 109,324 | 109,832 | 114,921 | 113,771 |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 78 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 22,333 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 109,554 | 109,482 | 109,447 | 109,355 | 107,890 | 102,977 | 94,842 | 82,729 | 63,704 |
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2012 [Member] | Homeowners [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 86,519 | 86,567 | 86,483 | 86,330 | 86,271 | 86,667 | 86,560 | 82,744 | 87,260 |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 44 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 16,942 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 85,899 | 85,897 | 85,642 | 85,562 | 85,196 | 84,250 | 82,720 | 79,584 | 69,056 |
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2013 [Member] | Personal Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 107,803 | 107,916 | 107,680 | 107,759 | 106,703 | 106,225 | 109,620 | 108,417 |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 121 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 22,376 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 107,419 | 106,876 | 106,679 | 105,131 | 100,528 | 92,637 | 80,861 | 61,384 |  |
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2013 [Member] | Homeowners [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 71,948 | 72,318 | 72,148 | 71,714 | 72,145 | 71,494 | 72,528 | 73,670 |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 49 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 7,749 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 72,446 | 72,433 | 72,197 | 71,776 | 69,775 | 67,838 | 65,528 | 50,664 |  |
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2014 [Member] | Personal Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 107,106 | 107,104 | 106,821 | 107,452 | 106,757 | 109,325 | 102,250 |  |  |
Short-duration Insurance, Contracts Incurred But Not Reported (IBNR) Claims Liability, Net | $ (42) |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 22,508 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 106,478 | 105,709 | 104,055 | 99,173 | 92,589 | 83,739 | 62,519 |  |  |
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2014 [Member] | Homeowners [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 83,525 | 83,824 | 83,539 | 83,844 | 83,637 | 82,461 | 80,111 |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 442 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 8,773 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 82,831 | 82,836 | 82,583 | 81,664 | 79,751 | 76,007 | 61,561 |  |  |
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2015 [Member] | Personal Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 98,588 | 98,718 | 99,570 | 100,214 | 99,698 | 96,387 |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 295 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 20,865 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 97,275 | 95,997 | 92,102 | 87,163 | 76,470 | 58,725 |  |  |  |
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2015 [Member] | Homeowners [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 74,673 | 74,978 | 74,723 | 76,559 | 76,400 | 76,637 |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 483 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 7,750 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 74,052 | 74,079 | 72,927 | 72,202 | 70,078 | 52,589 |  |  |  |
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2016 [Member] | Personal Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 99,544 | 101,140 | 100,202 | 98,032 | 92,727 |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 452 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 19,824 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 98,080 | 94,372 | 86,752 | 76,823 | 57,961 |  |  |  |  |
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2016 [Member] | Homeowners [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 61,735 | 61,723 | 62,391 | 60,931 | 60,105 |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 442 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 6,892 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 61,187 | 60,082 | 59,546 | 57,333 | 42,252 |  |  |  |  |
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Personal Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 103,260 | 103,653 | 105,139 | 101,880 |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 1,607 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 20,739 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 97,628 | 91,479 | 82,730 | 62,854 |  |  |  |  |  |
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2017 [Member] | Homeowners [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 70,064 | 70,365 | 67,978 | 59,167 |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 1,822 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 7,385 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 67,767 | 67,193 | 63,290 | 45,466 |  |  |  |  |  |
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2018 [Member] | Personal Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 112,030 | 113,569 | 111,594 |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 5,597 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 22,668 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 99,982 | 89,628 | 69,721 |  |  |  |  |  |  |
Standard Personal Lines | Short-duration Insurance Contracts, Accident Year 2018 [Member] | Homeowners [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 69,832 | 68,526 | 62,961 |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 3,129 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 7,596 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 65,348 | 64,137 | 49,430 |  |  |  |  |  |  |
Standard Personal Lines | Short-Duration Insurance Contract, Accident Year 2019 [Member] | Personal Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 115,688 | 114,043 |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 13,260 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 22,804 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 92,162 | 69,699 |  |  |  |  |  |  |  |
Standard Personal Lines | Short-Duration Insurance Contract, Accident Year 2019 [Member] | Homeowners [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 72,772 | 64,306 |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 2,765 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 6,970 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 67,631 | 49,680 |  |  |  |  |  |  |  |
Standard Personal Lines | Short-Duration Insurance Contract, Accident Year 2020 | Personal Automobile [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 95,625 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 30,333 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 16,309 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 53,407 |  |  |  |  |  |  |  |  |
Standard Personal Lines | Short-Duration Insurance Contract, Accident Year 2020 | Homeowners [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 109,033 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 16,218 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 9,003 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 83,838 |  |  |  |  |  |  |  |  |
E&S Lines [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Reserve for loss and loss expense |  |  |  |  |  |  |  |  | 15,000 |
E&S Lines [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 816,172 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | 426,833 |  |  |  |  |  |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 389,460 |  |  |  |  |  |  |  |  |
E&S Lines [Member] | Short-Duration Insurance Contracts, Accident Years Prior to 2011 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Liability for Unpaid Claims and Claims Adjustment Expense, Net | 121 |  |  |  |  |  |  |  |  |
E&S Lines [Member] | Short-duration Insurance Contracts, Accident Year 2011 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 13,344 | 11,554 | 12,119 | 10,228 | 9,652 | 10,273 | 12,207 | 9,853 | 7,102 | 8,127
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 408 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 1,337 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 10,744 | 9,604 | 9,819 | 10,256 | 9,912 | 9,954 | 6,445 | 3,200 | 806 | $ 0
E&S Lines [Member] | Short-duration Insurance Contracts, Accident Year 2012 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 44,348 | 44,622 | 46,444 | 45,988 | 46,165 | 46,149 | 43,175 | 42,621 | 42,367 |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 2,126 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 2,055 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 40,615 | 39,832 | 38,298 | 36,278 | 32,343 | 25,064 | 16,430 | 7,914 | $ 3,722 |
E&S Lines [Member] | Short-duration Insurance Contracts, Accident Year 2013 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 68,029 | 68,451 | 68,972 | 67,647 | 69,112 | 67,099 | 60,309 | 55,468 |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 13,032 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 2,299 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 55,988 | 54,974 | 51,142 | 46,108 | 35,200 | 21,980 | 9,470 | $ 2,715 |  |
E&S Lines [Member] | Short-duration Insurance Contracts, Accident Year 2014 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 70,846 | 71,153 | 71,206 | 71,719 | 69,929 | 63,505 | 55,316 |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 2,352 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 2,101 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 64,698 | 60,092 | 53,780 | 43,877 | 25,571 | 12,234 | $ 2,353 |  |  |
E&S Lines [Member] | Short-duration Insurance Contracts, Accident Year 2015 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 90,126 | 90,355 | 90,488 | 82,404 | 76,432 | 75,498 |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 12,518 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 2,844 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 71,421 | 64,529 | 50,712 | 29,389 | 13,057 | $ 3,036 |  |  |  |
E&S Lines [Member] | Short-duration Insurance Contracts, Accident Year 2016 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 104,730 | 105,120 | 104,655 | 96,416 | 94,451 |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 25,507 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 2,925 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 69,448 | 56,581 | 33,950 | 16,195 | $ 3,720 |  |  |  |  |
E&S Lines [Member] | Short-duration Insurance Contracts, Accident Year 2017 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 99,395 | 99,866 | 95,783 | 91,438 |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 26,778 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 2,727 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 53,238 | 34,179 | 14,672 | $ 5,057 |  |  |  |  |  |
E&S Lines [Member] | Short-duration Insurance Contracts, Accident Year 2018 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 103,184 | 103,004 | 98,324 |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 41,204 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 2,637 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 39,174 | 21,337 | $ 5,509 |  |  |  |  |  |  |
E&S Lines [Member] | Short-Duration Insurance Contract, Accident Year 2019 [Member] | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 118,298 | 117,087 |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 78,482 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 2,278 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 17,812 | $ 4,422 |  |  |  |  |  |  |  |
E&S Lines [Member] | Short-Duration Insurance Contract, Accident Year 2020 | General Liability [Member] |  |  |  |  |  |  |  |  |  |
Claims Development [Line Items] |  |  |  |  |  |  |  |  |  |
Net outstanding liabilities | 103,872 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net | $ 90,970 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contract, Cumulative Number of Reported Claims | 1,138 |  |  |  |  |  |  |  |  |
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net | $ 3,695 |  |  |  |  |  |  |  |  |

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