XML 79 R62.htm IDEA: XBRL DOCUMENT v3.20.4
Segment Information - Summary of net premiums written and earned by major line of business and net premiums written by location (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2020
Sep. 30, 2020
Jun. 30, 2020
Mar. 31, 2020
Dec. 31, 2019
Sep. 30, 2019
Jun. 30, 2019
Mar. 31, 2019
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Segment Reporting Information [Line Items]                      
Net premiums earned $ 1,811,045 $ 1,771,092 $ 1,665,354 $ 1,744,444 $ 1,515,882 $ 1,438,023 $ 1,463,727 $ 1,368,866 $ 6,991,935 $ 5,786,498 $ 5,231,975
Net premiums written $ 1,758,015 $ 1,874,144 $ 1,668,311 $ 2,137,246 $ 1,455,453 $ 1,613,457 $ 1,444,898 $ 1,525,259 7,437,716 6,039,067 5,346,747
Other                      
Segment Reporting Information [Line Items]                      
Net premiums earned                 560,351 556,689 578,862
Net premiums written                 537,589 532,862 604,175
Other | United States                      
Segment Reporting Information [Line Items]                      
Net premiums written                 115,471 127,176 49,800
Other | Europe                      
Segment Reporting Information [Line Items]                      
Net premiums written                 97,753 52,065 91,635
Other | Bermuda                      
Segment Reporting Information [Line Items]                      
Net premiums written                 324,365 353,621 462,740
Other | Property excluding property catastrophe                      
Segment Reporting Information [Line Items]                      
Net premiums earned [1]                 1,130 3,503 2,802
Other | Property catastrophe                      
Segment Reporting Information [Line Items]                      
Net premiums earned [1]                 23,037 13,399 10,998
Other | Other specialty                      
Segment Reporting Information [Line Items]                      
Net premiums earned [1],[2]                 186,717 185,547 204,485
Other | Casualty                      
Segment Reporting Information [Line Items]                      
Net premiums earned [1],[3]                 245,272 246,894 277,589
Other | Marine and aviation                      
Segment Reporting Information [Line Items]                      
Net premiums earned                 429 0 0
Other | Other                      
Segment Reporting Information [Line Items]                      
Net premiums earned [1],[4]                 103,766 107,346 82,988
Underwriting segments                      
Segment Reporting Information [Line Items]                      
Net premiums earned                 6,431,584 5,229,809 4,653,113
Net premiums written                 6,900,127 5,506,205 4,742,572
Underwriting segments | Insurance                      
Segment Reporting Information [Line Items]                      
Net premiums earned                 2,871,420 2,397,080 2,205,661
Net premiums written                 3,162,907 2,641,726 2,212,125
Underwriting segments | Insurance | United States                      
Segment Reporting Information [Line Items]                      
Net premiums written [5]                 2,158,415 1,983,476 1,736,651
Underwriting segments | Insurance | Europe                      
Segment Reporting Information [Line Items]                      
Net premiums written [5]                 856,572 559,214 401,974
Underwriting segments | Insurance | Other geographic location                      
Segment Reporting Information [Line Items]                      
Net premiums written [5]                 147,920 99,036 73,500
Underwriting segments | Insurance | Property, energy, marine and aviation                      
Segment Reporting Information [Line Items]                      
Net premiums earned [5]                 517,247 298,966 205,069
Underwriting segments | Insurance | Professional lines                      
Segment Reporting Information [Line Items]                      
Net premiums earned [5],[6]                 655,872 499,224 458,425
Underwriting segments | Insurance | Programs                      
Segment Reporting Information [Line Items]                      
Net premiums earned [5]                 432,854 414,103 389,186
Underwriting segments | Insurance | Construction and national accounts                      
Segment Reporting Information [Line Items]                      
Net premiums earned [5]                 387,934 325,687 322,440
Underwriting segments | Insurance | Excess and surplus casualty                      
Segment Reporting Information [Line Items]                      
Net premiums earned [5],[7]                 270,620 200,615 172,424
Underwriting segments | Insurance | Travel, accident and health                      
Segment Reporting Information [Line Items]                      
Net premiums earned [5]                 190,944 305,085 297,147
Underwriting segments | Insurance | Lenders products                      
Segment Reporting Information [Line Items]                      
Net premiums earned [5]                 114,687 66,079 94,248
Underwriting segments | Insurance | Other                      
Segment Reporting Information [Line Items]                      
Net premiums earned [5],[8]                 301,262 287,321 266,722
Underwriting segments | Reinsurance                      
Segment Reporting Information [Line Items]                      
Net premiums earned                 2,162,229 1,466,389 1,261,216
Net premiums written                 2,457,370 1,602,723 1,372,572
Underwriting segments | Reinsurance | United States                      
Segment Reporting Information [Line Items]                      
Net premiums written [9]                 687,622 529,943 413,550
Underwriting segments | Reinsurance | Bermuda                      
Segment Reporting Information [Line Items]                      
Net premiums written [9]                 1,001,990 578,618 487,523
Underwriting segments | Reinsurance | Europe and other                      
Segment Reporting Information [Line Items]                      
Net premiums written                 767,758 494,162 471,499
Underwriting segments | Reinsurance | Property excluding property catastrophe                      
Segment Reporting Information [Line Items]                      
Net premiums earned [9],[10]                 562,208 362,841 287,788
Underwriting segments | Reinsurance | Property catastrophe                      
Segment Reporting Information [Line Items]                      
Net premiums earned [9],[11]                 237,736 90,934 75,249
Underwriting segments | Reinsurance | Other specialty                      
Segment Reporting Information [Line Items]                      
Net premiums earned [9],[10]                 626,409 478,517 474,568
Underwriting segments | Reinsurance | Casualty                      
Segment Reporting Information [Line Items]                      
Net premiums earned [9],[11]                 549,056 429,288 347,034
Underwriting segments | Reinsurance | Marine and aviation                      
Segment Reporting Information [Line Items]                      
Net premiums earned [9]                 109,624 48,274 39,238
Underwriting segments | Reinsurance | Other                      
Segment Reporting Information [Line Items]                      
Net premiums earned [9],[12]                 77,196 56,535 37,339
Underwriting segments | Mortgage                      
Segment Reporting Information [Line Items]                      
Net premiums earned                 1,397,935 1,366,340 1,186,236
Net premiums written                 1,279,850 1,261,756 1,157,875
Underwriting segments | Mortgage | United States                      
Segment Reporting Information [Line Items]                      
Net premiums earned                 1,158,563 1,134,849 1,009,765
Net premiums written                 1,021,950 1,032,868 948,323
Underwriting segments | Mortgage | Other geographic location                      
Segment Reporting Information [Line Items]                      
Net premiums earned                 239,372 231,491 176,471
Net premiums written                 $ 257,900 $ 228,888 $ 209,552
[1] Other segment results include premiums assumed through intersegment transactions and exclude premiums ceded through intersegment transactions.
[2] Includes proportional motor and other.
[3] Includes professional liability, excess motor, programs and other.
[4] Includes mortgage, US programs and other.
[5] Insurance segment results include premiums assumed through intersegment transactions and exclude premiums ceded through intersegment transactions.
[6] Includes professional liability, executive assurance and healthcare business.
[7] Includes casualty and contract binding business.
[8] Includes alternative markets, excess workers' compensation and surety business.
[9] Reinsurance segment results include premiums assumed through intersegment transactions and exclude premiums ceded through intersegment transactions.
[10] Includes proportional motor, surety, accident and health, workers’ compensation catastrophe, agriculture, trade credit and other.
[11] Includes executive assurance, professional liability, workers’ compensation, excess motor, healthcare and other.
[12] Includes life, casualty clash and other.