Business Segments - Segment Information (Details) $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($) segment	Mar. 31, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of Operating Segments | segment	2
Earned Premiums	$ 563.4	$ 546.0
Net Investment Income	81.6	67.0
Other Income	0.9	0.8
Total Revenues	651.4	611.3
Net Realized Gains on Sales of Investments	10.5	6.8
Net Impairment Losses Recognized in Earnings	(5.0)	(9.3)
Segment Operating Profit (Loss)	(9.0)	(4.0)
Total Before Income Taxes	(3.5)	(6.5)
Segment Net Operating Income (Loss)	(3.9)	(0.6)
Loss from Continuing Operations	(0.4)	(2.2)
Corporate, Non-Segment [Member]
Segment Reporting Information [Line Items]
Segment Operating Profit (Loss)	(4.4)	(12.2)
Segment Net Operating Income (Loss)	(3.3)	(7.8)
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Other Income	4.6	0.1
Net Realized Gains on Sales of Investments	10.5	6.8
Net Impairment Losses Recognized in Earnings	(5.0)	(9.3)
Net Realized Gains (Losses) on Sales of Investments, Net of Tax	6.8	4.4
Net Impairment Losses Recognized in Earnings, Net of Tax	(3.3)	(6.0)
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total Revenues	641.3	613.7
Segment Operating Profit (Loss)	(4.6)	8.2
Loss from Continuing Operations	(0.6)	7.2
Operating Segments [Member] | Property and Casualty Insurance [Member]
Segment Reporting Information [Line Items]
Earned Premiums	410.4	396.2
Net Investment Income	24.1	11.9
Other Income	0.2	0.2
Total Revenues	434.7	408.3
Segment Operating Profit (Loss)	(37.2)	(22.8)
Loss from Continuing Operations	(22.1)	(13.1)
Operating Segments [Member] | Life and Health Insurance [Member]
Segment Reporting Information [Line Items]
Earned Premiums	153.0	149.8
Net Investment Income	53.0	55.0
Other Income	0.6	0.6
Total Revenues	206.6	205.4
Segment Operating Profit (Loss)	32.6	31.0
Loss from Continuing Operations	$ 21.5	$ 20.3