Summary of Significant Accounting Policies (Schedule of Trust Assets and Reinsurance Liabilities) (Details) - USD ($) $ in Millions		Sep. 30, 2015	Dec. 31, 2014
Summary Of Significant Accounting Policies [Line Items]
Restricted cash and cash equivalents		$ 176.0	$ 157.6
Restricted securities available for sale		50.5	53.2
Accounts payable and accrued liabilities		124.2	114.4
Trust Assets [Member]
Summary Of Significant Accounting Policies [Line Items]
Restricted cash and cash equivalents		0.6	0.2
Restricted securities available for sale		50.5	53.2
Unearned Premium [Member]
Summary Of Significant Accounting Policies [Line Items]
Accounts payable and accrued liabilities		37.6	38.4
Claims Reserve [Member]
Summary Of Significant Accounting Policies [Line Items]
Accounts payable and accrued liabilities	[1]	$ 1.4	$ 1.5

[1] The claims reserve is estimated based on historical claims experience.