v3.26.1
Investments - Change in Net Unrealized Gains (Losses) on Available-for-Sale Securities (Details) - USD ($)
$ in Thousands
3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Roll Forward]    
Beginning balance $ 5,355,181 $ 4,996,096
Change in net unrealized investment gains (losses) (50,720) 58,894
Ending balance 5,343,548 5,119,407
Reclassification adjustments to net investment (gains) losses, tax (1,220) (657)
Amounts reclassified from accumulated other comprehensive income (loss)    
Debt Securities, Available-for-sale, Unrealized Gain (Loss) [Roll Forward]    
Beginning balance (24,591) (207,624)
Unrealized gains (losses) on investment securities (70,370) 71,848
Provision for income taxes 15,060 (15,425)
Change in unrealized gains (losses) on investment securities (55,310) 56,423
Reclassification adjustments to net investment (gains) losses, net of taxes of $(1,220) and $(657), respectively 4,590 2,471
Change in net unrealized investment gains (losses) (50,720) 58,894
Ending balance $ (75,311) $ (148,730)