Business Segments - Earned Premiums by Product Line (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Life	$ 95.5	$ 96.8	$ 279.5	$ 291.6
Earned Premiums, Accident and Health	36.2	37.1	108.7	112.1
Earned Premiums, Total	536.7	462.8	1,468.1	1,410.7
Personal Automobile [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	288.5	205.1	730.9	633.4
Homeowners [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	72.1	77.9	216.3	236.6
Other Personal Property and Casualty Insurance [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	30.7	31.8	92.0	96.2
Commercial Automobile [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	$ 13.7	$ 14.1	$ 40.7	$ 40.8