Catastrophe Reinsurance - Catastrophe Reinsurance Premiums (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Liability for Catastrophe Claims [Line Items]
Ceded Catastrophe Reinsurance Premiums	$ 20.6	$ 26.0	$ 33.9
Catastrophe Reinsurance [Member]
Liability for Catastrophe Claims [Line Items]
Ceded Catastrophe Reinsurance Premiums	12.9	17.7	23.6
Property and Casualty Insurance [Member] | Catastrophe Reinsurance [Member]
Liability for Catastrophe Claims [Line Items]
Ceded Catastrophe Reinsurance Premiums	12.8	17.6	23.6
Life and Health Insurance [Member] | Catastrophe Reinsurance [Member]
Liability for Catastrophe Claims [Line Items]
Ceded Catastrophe Reinsurance Premiums	$ 0.1	$ 0.1	$ 0.0