Historical Loss and LAE Development - Reconciliation of Unpaid Losses and Settlement Expenses (LAE) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Unpaid losses and LAE at beginning of year
Gross	$ 2,693,470	$ 2,446,025
Ceded	(755,425)	(757,349)
Net	1,938,045	1,688,676
Increase (decrease) in incurred losses and LAE
Current accident year	623,926	599,183
Prior accident year	(74,112)	(85,442)
Total incurred	549,814	513,741
Loss and LAE payments for claims incurred
Current accident year	(74,868)	(76,148)
Prior accident years	(309,548)	(273,868)
Total paid	(384,416)	(350,016)
Net unpaid losses and LAE at end of year	2,103,443	1,852,401
Unpaid losses and LAE at end of year
Gross	2,873,054	2,611,941
Ceded	(769,611)	(759,540)
Net unpaid losses and LAE at end of year	$ 2,103,443	$ 1,852,401