Loss And Loss Adjustment Expense Reserves - Reconciliation of the Disclosure of Incurred and Paid Claims Development to the Loss and Loss Adjustment Expense Reserves (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net outstanding liabilities	$ 2,607,862
Reinsurance recoverables on unpaid losses	32,148
Insurance lines other than short-duration	1,072
Unallocated claims adjustment expenses	144,620
Unallocated claims adjustment expenses, aggregate reconciling items	145,692
Total gross loss and loss adjustment expense reserves	2,785,702	$ 2,584,910	$ 2,226,430	$ 1,991,304
Property insurance product line, automobile
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net outstanding liabilities	2,009,595
Reinsurance recoverables on unpaid losses	27,528
Property insurance product line, homeowners'
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net outstanding liabilities	362,198
Reinsurance recoverables on unpaid losses	3,903
Other Short-duration Insurance Product Line
Short-duration Insurance Contracts, Reconciliation of Claims Development to Liability [Line Items]
Net outstanding liabilities	236,069
Reinsurance recoverables on unpaid losses	$ 717