Reinsurance - Schedule of Direct, Assumed, and Ceded Reinsurance Amounts (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Premiums written:
Direct	$ 1,490,805	$ 1,399,738	$ 2,913,656	$ 2,715,649
Assumed	5,441	6,413	11,418	12,398
Ceded	(207,617)	(180,050)	(396,002)	(345,325)
Net	1,288,629	1,226,101	2,529,072	2,382,722
Premiums earned:
Direct	1,373,080	1,242,696	2,713,526	2,448,064
Assumed	5,922	5,779	12,073	11,970
Ceded	(190,945)	(168,244)	(378,785)	(328,859)
Net	1,188,057	1,080,231	2,346,814	2,131,175
Loss and loss expense incurred:
Direct	929,929	1,009,819	1,760,601	1,763,386
Assumed	5,137	5,058	10,635	11,039
Ceded	(111,168)	(89,329)	(201,013)	(144,585)
Net	$ 823,898	$ 925,548	$ 1,570,223	$ 1,629,840

Amount of earned premiums assumed from other entities.

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Amount, before effect of policies assumed or ceded, of expense related to provision for policy benefits and costs incurred.

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Amount, after effects of policies assumed or ceded, of expense related to the provision for policy benefits and costs incurred.

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Amount of policy benefits and costs incurred for policies assumed.

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