Historical Loss and LAE Development - Reconciliation of Unpaid Losses and Settlement Expenses (LAE) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023
Unpaid losses and LAE at beginning of year
Gross	$ 2,446,025	$ 2,315,637
Ceded	(757,349)	(740,089)
Net	1,688,676	1,575,548
Increase (decrease) in incurred losses and LAE
Current accident year	599,183	551,975
Prior accident years	(85,442)	(93,986)
Total incurred	513,741	457,989
Loss and LAE payments for claims incurred
Current accident year	(76,148)	(113,010)
Prior accident years	(273,868)	(252,786)
Total paid	(350,016)	(365,796)
Net unpaid losses and LAE at June 30	1,852,401	1,667,741
Unpaid losses and LAE at June 30
Gross	2,611,941	2,488,695
Ceded	(759,540)	(820,954)
Net unpaid losses and LAE at June 30	$ 1,852,401	$ 1,667,741