Reinsurance (Schedule of Trust Assets and Reinsurance Liabilities) (Details) - USD ($) $ in Millions		Mar. 31, 2020	Dec. 31, 2019
Trust Assets [Member]
Reinsurance [Line Items]
Restricted cash and cash equivalents		$ 0.9	$ 0.9
Restricted securities available for sale		63.2	59.3
Unearned Premium [Member]
Reinsurance [Line Items]
Accounts payable and accrued liabilities		48.5	44.1
Claims Reserve [Member]
Reinsurance [Line Items]
Accounts payable and accrued liabilities	[1]	$ 2.1	$ 1.8

[1] The claims reserve represents our liability for incurred-but-not-reported claims and is estimated based on historical claims experience.