Other Liabilities and Accrued Expenses - Summary (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Other Liabilities Disclosure [Abstract]
Ceding commission payable	$ 25.4	$ 13.9
Lease liabilities	23.4	28.2
Uncertain tax position	16.4	13.3
Accrued advertising costs	11.1	6.2
Employee compensation	7.5	8.4
Premium taxes payable	5.0	5.9
Advance premium	4.5	3.4
Accrued professional fees	4.4	5.0
Reinsurance payable	4.3	0.8
Income taxes payable	2.0	1.2
Other payables	17.2	13.2
Total	$ 121.2	$ 99.5