v3.26.3
Investments - Schedule of Unrealized Loss on Investments (Details) - USD ($)
$ in Thousands
Sep. 30, 2026
Dec. 31, 2025
Debt Securities, Available-for-sale [Line Items]    
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months $ 1,936,851 $ 318,264
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 103,350 1,482
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer 682,880 996,720
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 148,032 98,641
Debt Securities, Available-for-sale, Unrealized Loss Position 2,619,731 1,314,984
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss 251,382 100,123
Obligations of U.S. Government-sponsored enterprises    
Debt Securities, Available-for-sale [Line Items]    
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months 78,193 13,971
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 4,291 22
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer 53,415 149,230
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 4,561 5,069
Debt Securities, Available-for-sale, Unrealized Loss Position 131,608 163,201
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss 8,852 5,091
Obligations of states and political subdivisions    
Debt Securities, Available-for-sale [Line Items]    
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months 190,304 32,658
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 19,057 245
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer 335,850 425,879
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 97,488 57,864
Debt Securities, Available-for-sale, Unrealized Loss Position 526,154 458,537
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss 116,545 58,109
Agency mortgage-backed securities    
Debt Securities, Available-for-sale [Line Items]    
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months 1,536,059 266,639
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 79,677 1,215
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer 291,653 377,787
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 45,945 35,115
Debt Securities, Available-for-sale, Unrealized Loss Position 1,827,712 644,426
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss 125,622 36,330
U.S. Treasury bills    
Debt Securities, Available-for-sale [Line Items]    
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months 987 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 13 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer 1,962 3,406
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 38 94
Debt Securities, Available-for-sale, Unrealized Loss Position 2,949 3,406
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss 51 94
Corporate debt securities    
Debt Securities, Available-for-sale [Line Items]    
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months 131,308 4,996
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 312 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer 0 40,418
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 0 499
Debt Securities, Available-for-sale, Unrealized Loss Position 131,308 45,414
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss $ 312 $ 499