Loss and Loss Adjustment Expense Reserves (Loss and Loss Adjustment Expense) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	9 Months Ended
Sep. 30, 2016	Sep. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Equity in earnings of unconsolidated affiliates, net of tax	$ 0.0	$ 3.9			$ 0.0	$ 18.0
Gross beginning balance	1,376.6	1,350.8	$ 1,389.8	$ 1,342.2	1,389.8	1,342.2
Less beginning reinsurance recoverable on unpaid losses	(162.8)	(147.1)	(186.0)	(161.6)	(186.0)	(161.6)
Net loss and LAE reserves	1,213.8	1,203.7	1,203.8	1,180.6	1,203.8	1,180.6
Loss and LAE incurred relating to current year losses	164.9	170.4			492.8	536.7
Net (favorable) and unfavorable loss reserve development	0.1	(0.4)			15.3	(2.6)
Total incurred losses and LAE	165.0	170.0			508.1	534.1
Current year losses	(55.0)	(53.0)			(116.2)	(120.2)
Prior year losses	(131.1)	(108.1)			(403.2)	(383.5)
Total loss and LAE payments	(186.1)	(161.1)			(519.4)	(503.7)
Net ending balance	1,192.6	1,213.2	1,213.8	1,203.7	1,192.6	1,213.2
Plus ending reinsurance recoverable on unpaid losses	169.4	214.2	162.8	147.1	169.4	214.2
Gross ending balance	1,362.0	1,427.4	$ 1,376.6	$ 1,350.8	1,362.0	1,427.4
Star & Shield Insurance Exchange
Net ending balance	5.4	5.5			5.4	5.5
Star & Shield Insurance Exchange
Liability for Unpaid Claims and Claims Adjustment Expense, Consolidated Claims Current Year	5.3	6.1			5.5	7.7
Net (favorable) and unfavorable loss reserve development	$ 0.1	$ (0.4)			$ (0.1)	$ (0.8)

This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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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 of payments to settle claims incurred in the current period and related claims settlement costs.

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Amount of payments to settle claims incurred in prior periods and related claims settlement costs.

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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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The amount of the other adjustment made to the claims reserves during the period.

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

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Estimated amount after valuation allowance of reinsurance recoverables, due from reinsurers for incurred claims not yet reported, and claims settlement expenses.

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

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

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