Summary Of Accounting Policies And Accounting Changes (Details) - USD ($) $ in Millions		3 Months Ended								12 Months Ended
	Jan. 01, 2017	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 01, 2018
Accounting Policy Disclosures [Line Items]
Policyholders’ Benefits and Incurred Losses and Loss Adjustment Expenses		$ 472.5	$ 440.1	$ 447.4	$ 477.4	$ 418.3	$ 490.2	$ 436.1	$ 436.2	$ 1,837.4	$ 1,780.8	$ 1,467.6
Reinsurance Recoverables, Including Reinsurance Premium Paid		111.6				106.4				111.6	106.4
Accrued Investment Income Receivable		72.8				70.8				72.8	70.8
Write-off of long-lived asset										0.0	0.0	$ 11.1
Expected Amortization Expense of Ending Present Value of Future Insurance Profits, Net of Interest Accrued [Abstract]
Deferred Policy Acquisition Costs		365.3				332.0				365.3	332.0
Life Insurance Product Line [Member]
Accounting Policy Disclosures [Line Items]
Present value of the future profits embedded in life insurance in force		25.5				28.9				25.5	28.9
Expected Amortization Expense of Ending Present Value of Future Insurance Profits, Net of Interest Accrued [Abstract]
2018										3.0
2019										2.8
2020										2.3
2021										2.0
2022										1.9
Property and Casualty Insurance [Member]
Accounting Policy Disclosures [Line Items]
Present value of the future profits embedded in life insurance in force		7.3				9.0				7.3	9.0
Broker Relationships [Member]
Expected Amortization Expense of Ending Present Value of Future Insurance Profits, Net of Interest Accrued [Abstract]
Assets acquired		$ 15.6				16.8				$ 15.6	16.8
Useful life of intangibles acquired (in years)										15 years
Minimum [Member] | Traditional Life [Member]
Accounting Policy Disclosures [Line Items]
Liability for Future Policy Benefits, Interest Rate		3.00%								3.00%
Maximum [Member] | Traditional Life [Member]
Accounting Policy Disclosures [Line Items]
Liability for Future Policy Benefits, Interest Rate		7.00%								7.00%
Change in Accounting Method Accounted for as Change in Estimate [Member]
Expected Amortization Expense of Ending Present Value of Future Insurance Profits, Net of Interest Accrued [Abstract]
Pension Expense											(2.7)
Change in Accounting Estimate, Use of Death Master File in Reserving Process [Member]
Accounting Policy Disclosures [Line Items]
Policyholders’ Benefits and Incurred Losses and Loss Adjustment Expenses										$ 77.8
Premium Deficiency [Member]
Expected Amortization Expense of Ending Present Value of Future Insurance Profits, Net of Interest Accrued [Abstract]
Deferred Policy Acquisition Costs		$ (1.2)				$ (9.7)				$ (1.2)	$ (9.7)
Accounting Standards Update 2016-09 [Member]
Expected Amortization Expense of Ending Present Value of Future Insurance Profits, Net of Interest Accrued [Abstract]
Cumulative Effect on Retained Earnings, Net of Tax	$ 0.5
Subsequent Event [Member] | Retained Earnings [Member] | Accounting Standards Update 2016-01 [Member]
Accounting Policy Disclosures [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets													$ 17.7