Reinsurance - Schedule of Direct, Assumed, and Ceded Reinsurance Amounts (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Premiums written:
Direct	$ 1,399,738	$ 1,232,496	$ 2,715,649	$ 2,365,256
Assumed	6,413	5,577	12,398	10,971
Ceded	(180,050)	(153,166)	(345,325)	(291,552)
Net	1,226,101	1,084,907	2,382,722	2,084,675
Premiums earned:
Direct	1,242,696	1,073,498	2,448,064	2,105,726
Assumed	5,779	5,968	11,970	12,258
Ceded	(168,244)	(137,316)	(328,859)	(273,498)
Net	1,080,231	942,150	2,131,175	1,844,486
Loss and loss expense incurred:
Direct	1,009,819	698,994	1,763,386	1,312,223
Assumed	5,058	5,678	11,039	10,933
Ceded	(89,329)	(58,542)	(144,585)	(109,588)
Net	$ 925,548	$ 646,130	$ 1,629,840	$ 1,213,568