Description of Business and Summary of Significant Accounting Policies - Deferred Policy Acquisition Costs (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Accounting Policies [Abstract]
Amortization expense	$ 9.8	$ 10.0	$ 17.5	$ 23.1

Amount of amortization expense (reversal of expense) for deferred policy acquisition costs.

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