Basis of Presentation and Summary of Significant Accounting Policies - Reinsurance - Additional Information (Details) - USD ($)	9 Months Ended
Sep. 30, 2024	Dec. 31, 2023
Reinsurance
Amount of allowance for uncollectible amounts on paid recoverables	$ 16,000,000	$ 16,000,000
Reinsurance balances recoverable on unpaid losses and settlement expenses, allowances for uncollectible amounts	10,055,000	$ 10,608,000
Financing receivable, allowance for credit Loss, write-off	0
Maximum
Reinsurance
Financing receivable, allowance for credit loss, recovery	$ 1,000,000

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of increase in allowance for credit loss on financing receivable from recovery.

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Amount of valuation allowance for reinsurance recoverables on paid losses.

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Amount of valuation allowance for reinsurance recoverables for losses reported to the ceding insurer but not yet paid, and for amounts expected based upon statistical projections and other measures of incurred losses and loss settlement expenses which have not yet been reported to the ceding insurer.

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