Description of Business and Summary of Significant Accounting Policies - Accounts Receivable and Long term Insurance Commissions Receivable (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Allowance for uncollectible receivables	$ 0.6		$ 0.5
Deferred policy acquisition costs	17.7		$ 8.7
Amortized deferred acquisition costs	$ 9.3	$ 3.0