Description of Business and Summary of Significant Accounting Policies - Cash and cash equivalents (Details) $ in Millions	Sep. 30, 2023 USD ($) state	Dec. 31, 2022 USD ($) state
Accounting Policies [Abstract]
Restricted cash equivalents	$ 7.7
Restricted cash pledged against obligations to policyholders and creditors	0.6	$ 1.0
Restricted funds held for payment of possible warranty claims	$ 8.0	$ 5.0
Number of states regulatory guidelines of warranty claims | state	17	19
Indemnification hold back cost	$ 2.4	$ 2.4
Restricted cash pledged as collateral		$ 5.1