Segment Information - Schedule of Segment Reporting Information, by Segment (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2026	Mar. 31, 2026	Jun. 30, 2025	Mar. 31, 2025	Jun. 30, 2026	Jun. 30, 2025
Segment Reporting [Line Items]
Total revenue	$ 294.4		$ 164.1		$ 552.4	$ 315.3
less: Loss and loss adjustment expenses, net	154.0		77.5		287.3	162.9
Other insurance expense	26.7		21.4		50.8	47.5
Sales and marketing	77.7		59.6		143.8	102.8
Technology development	30.0		22.4		56.9	44.4
Income tax expense	1.6		1.3		2.8	2.3
Net loss	(43.4)	$ (35.8)	(43.9)	$ (62.4)	(79.2)	(106.3)
Income Tax Jurisdiction, Domestic Federal | CARES Act, ERC Program
Segment Reporting [Line Items]
Tax credits received under ERC program					11.7	11.7
Reportable Segment
Segment Reporting [Line Items]
Total revenue	294.4		164.1		552.4	315.3
less: Loss and loss adjustment expenses, net	154.0		77.5		287.3	162.9
Other insurance expense	26.7		21.4		50.8	47.5
Sales and marketing	13.3		9.9		25.1	15.0
Advertising expenses	64.4		49.7		118.7	87.8
Technology development	30.0		22.4		56.9	44.4
General and administrative	38.4		28.8		73.4	56.9
Interest expense	7.0		4.0		13.2	7.3
Depreciation and amortization	2.4		4.7		5.1	9.2
Other expenses	0.0		(11.7)		(1.7)	(11.7)
Income tax expense	1.6		1.3		2.8	2.3
Net loss	$ (43.4)		$ (43.9)		(79.2)	$ (106.3)
Other expenses					$ 1.7