Loss and Loss Adjustment Expense Reserves (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2021
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Gross beginning balance	$ 760.0	$ 696.0
Less: beginning reinsurance recoverable on unpaid losses	(425.3)	(433.4)
Net loss and LAE reserves	334.7	262.6
Loss and LAE incurred relating to:
Current year losses	141.9	269.0
Prior year losses	(12.7)	(21.2)
Total incurred losses and LAE	129.2	247.8
Foreign currency translation adjustment to loss and LAE reserves	(1.2)	(3.4)
Loss and LAE paid relating to:
Current year losses	(9.0)	(11.5)
Prior year losses	(20.3)	(62.1)
Total loss and LAE payments	(29.3)	(73.6)
Net ending balance	433.4	433.4
Plus: ending reinsurance recoverable on unpaid losses	457.5	457.5
Gross ending balance	$ 890.9	$ 890.9
Prior year claims and claims adjustment expense, points	6.00%	5.00%

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 of foreign currency gain (loss) which decreases (increases) the cost of settling unpaid claims after deduction of reinsurance recoveries. Includes, but is not limited to, claims which have been incurred but not reported.

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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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Sum of adjustments to the estimated reserve for unpaid claims and claims adjustment expense.

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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 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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Prior Year Claims and Claims Adjustment Expense, Points

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