SHARE-BASED COMPENSATION - Schedule of Share-Based Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	$ 5.0	$ 8.4	$ 16.0	$ 14.8
Income Statement Location [Axis]: us-gaap:GeneralAndAdministrativeExpense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	0.8	5.6	7.7	9.6
Income Statement Location [Axis]: us-gaap:LiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseIncurredClaims1
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	0.7	0.8	1.9	1.4
Income Statement Location [Axis]: us-gaap:SellingAndMarketingExpense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	0.4	0.3	0.7	0.5
Income Statement Location [Axis]: root:OtherInsuranceExpenseIncome
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	0.5	0.2	0.9	0.5
Income Statement Location [Axis]: root:TechnologyAndDevelopmentExpense
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Total share-based compensation expense	$ 2.6	$ 1.5	$ 4.8	$ 2.8