Business Segments - Earned Premiums by Product Line (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Life	$ 96.0	$ 97.2	$ 184.0	$ 194.8
Earned Premiums, Accident and Health	35.7	36.2	72.5	75.0
Earned Premiums, Total	500.1	470.3	931.4	947.9
Personal Automobile [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	252.6	212.0	442.4	428.3
Homeowners [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	71.6	79.0	144.2	158.7
Other Personal Property and Casualty Insurance [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	30.7	32.3	61.3	64.4
Commercial Automobile [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	$ 13.5	$ 13.6	$ 27.0	$ 26.7