Stock-based Compensation - Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 61.3	$ 64.5	$ 59.9
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	25.2	29.8	37.6
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	41.3	28.2	19.8
Warrant shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	(5.2)	6.5	2.5
Loss and loss adjustment expense, net
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	2.3	2.1	2.8
Other insurance expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	2.9	2.5	2.2
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	(1.5)	10.6	6.4
Technology development
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	29.1	26.2	25.7
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 28.5	$ 23.1	$ 22.8