LOSS AND LOSS ADJUSTMENT EXPENSE RESERVES (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Gross loss and LAE reserves, January 1			$ 237.2	$ 140.7
Reinsurance recoverable on unpaid losses			(79.6)	(18.9)
Net loss and LAE reserves, January 1			157.6	121.8
Net incurred loss and LAE related to:
Current year			178.7	213.7
Prior years			(8.6)	13.0
Total incurred	$ 110.2	$ 97.3	170.1	227.2
Net paid loss and LAE related to:
Current year			81.3	105.9
Prior years			55.7	83.5
Total paid			137.0	189.4
Net loss and LAE reserves, June 30	190.7	159.1	190.7	159.1
Plus reinsurance recoverable on unpaid losses	81.8	31.2	81.8	31.2
Gross loss and LAE reserves, June 30	$ 272.5	$ 190.3	$ 272.5	$ 190.3

The amount needed to reflect the estimated ultimate cost of settling claims relating to insured events that have occurred on or before the balance sheet date, whether or not reported to the insurer at that date.

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Amount, after effects of reinsurance, of payments to settle claims incurred in the current period and related claims settlement costs.

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Amount, after effects of reinsurance, of payments to settle claims incurred in prior periods and related claims settlement costs.

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Amount, after effects of reinsurance, of expense (reversal of expense) for claims incurred and costs incurred in the claim settlement process.

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Liability as of the balance sheet date for amounts representing estimated cost of settling unpaid claims under the terms of the underlying insurance policies, less estimated reinsurance recoveries on such claims. This includes an estimate for claims which have been incurred but not reported. Claim adjustment expenses represent the costs estimated to be incurred in the settlement of unpaid claims.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount, after effects of reinsurance, of payments to settle insured claims and pay costs incurred in the claims settlement process.

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Amount, after valuation allowance, recoverable under reinsurance contracts for losses reported to the ceding insurer but not yet paid and amounts expected for incurred losses and settlement expenses, which have not yet been reported to the ceding insurer.

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Amount, after effects of reinsurance, of expense for claims incurred in the current reporting period and related claims settlement costs.

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Amount, after effects of reinsurance, of expense (reversal of expense) for claims incurred in prior reporting periods and related claims settlement costs.

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