BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Deferred Policy Acquisition Costs (Details) $ in Millions	6 Months Ended
Jun. 30, 2024 USD ($) segment	Jun. 30, 2023 USD ($)
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Balance, January 1	$ 18.0	$ 6.7
Acquisition costs deferred	21.1	14.9
Amortization expense	(15.7)	(11.1)
Balance, June 30	$ 23.4	$ 10.5
Number of reportable segments \| segment	1

Amount of amortization expense (reversal of expense) for deferred policy acquisition costs.

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Name:	us-gaap_DeferredPolicyAcquisitionCostAmortizationExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration