v3.26.1
Schedule of Total Investment Return (Detail) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Investments, Debt and Equity Securities [Abstract]        
Net investment income $ 16,361 $ 14,707 $ 28,579 $ 29,489
Net realized investment losses 198 127 (2,045) 263
Change in unrealized holding gains (losses) (222) 2,833 (3,515) 7,216
Net realized and unrealized investment returns (24) 2,960 (5,560) 7,479
Total investment return $ 16,337 $ 17,667 $ 23,019 $ 36,968
Total investment return % [1] 1.20% 1.20% 1.60% 2.60%
Average investment portfolio [2] $ 1,381,084 $ 1,432,379 $ 1,395,935 $ 1,436,827
[1] Not annualized.
[2] Average of total cash and invested assets, net of receivable/payable for securities, as of the beginning and end of the period.