Business Segments - Earned Premiums by Product Line (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Life	$ 88.0	$ 97.6
Earned Premiums, Accident and Health	36.8	38.8
Earned Premiums, Total	431.3	477.6
Personal Automobile [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	189.8	216.3
Homeowners [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	72.6	79.7
Other Personal Property and Casualty Insurance [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	30.6	32.1
Commercial Automobile [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	$ 13.5	$ 13.1