Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Deferred tax assets
Net unrealized loss on investments	$ 93,201	$ 88,065
State income taxes	46,463	46,170
Unearned premiums	24,928	24,948
Goodwill and intangibles	24,393	29,197
Capitalized research and development	16,060	12,450
Accrued expenses	11,983	10,829
Other	42,562	43,227
Total gross deferred tax assets	259,590	254,886
Less: Valuation allowance	66,590	63,354
Total deferred tax assets	193,000	191,532
Deferred tax liabilities
Contingency reserve	925,152	755,481
Other	14,533	25,615
Total deferred tax liabilities	939,685	781,096
Net deferred tax asset (liability)	$ (746,685)	$ (589,564)