Summary Of Significant Accounting Policies (Schedule Of Trust Assets And Reinsurance Liabilities) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Summary Of Significant Accounting Policies [Line Items]
Restricted cash and cash equivalents	$ 116.3	$ 92.4
Restricted securities available for sale	47.5	46.1
Accounts payable and accrued liabilities	105.2	105.8
Trust Assets [Member]
Summary Of Significant Accounting Policies [Line Items]
Restricted cash and cash equivalents	2.4	2.2
Restricted securities available for sale	47.5	46.1
Unearned Premium [Member]
Summary Of Significant Accounting Policies [Line Items]
Accounts payable and accrued liabilities	40.0	35.7
Claims Reserve [Member]
Summary Of Significant Accounting Policies [Line Items]
Accounts payable and accrued liabilities	$ 1.5	$ 1.4