Business Segments - Earned Premiums by Product Line (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Life	$ 97.6	$ 97.9
Earned Premiums, Accident and Health	38.8	40.2
Earned Premiums, Total	477.6	509.9
Personal Lines [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	328.1	359.7
Automobile [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	216.3	245.7
Homeowners [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	79.7	80.4
Other Personal Lines [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	32.1	33.6
Commercial Automobile [Member]
Entity-Wide Information, Revenue from External Customer [Line Items]
Earned Premiums, Property and Casualty	$ 13.1	$ 12.1