Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues
Premiums	$ 1,226.9	$ 1,160.9	$ 3,589.4	$ 3,457.7
Net investment income	76.6	67.8	220.0	205.2
Net realized investment gains (losses):
Net realized gains from sales and other	14.7	4.3	25.7	31.0
Net other–than–temporary impairment losses on investments recognized in earnings	(1.3)	(0.1)	(4.5)	(26.0)
Total net realized investment gains	13.4	4.2	21.2	5.0
Fees and other income	8.3	8.3	21.6	22.9
Total revenues	1,325.2	1,241.2	3,852.2	3,690.8
Losses and expenses
Losses and loss adjustment expenses	878.0	692.0	2,369.5	2,121.3
Amortization of deferred acquisition costs	275.1	257.9	806.1	771.4
Interest expense	12.1	12.5	36.3	42.8
Net loss from repayment of debt				86.1
Other operating expenses	151.1	154.7	461.4	444.1
Total losses and expenses	1,316.3	1,117.1	3,673.3	3,465.7
Income before income taxes	8.9	124.1	178.9	225.1
Income tax expense (benefit):
Current	7.3	8.0	46.1	47.9
Deferred	(10.7)	27.8	(3.1)	8.9
Total income tax (benefit) expense	(3.4)	35.8	43.0	56.8
Income from continuing operations	12.3	88.3	135.9	168.3
Net (loss) gain from discontinued operations (net of tax benefit (expense) of $0.8 for the three and nine months ended September 30, 2017 and $(0.1) and $2.1 for the three and nine months ended September 30, 2016, respectively)	(1.2)	0.1	(1.2)	0.3
Net income	$ 11.1	$ 88.4	$ 134.7	$ 168.6
Basic:
Income from continuing operations	$ 0.29	$ 2.07	$ 3.20	$ 3.93
Net gain from discontinued operations	(0.03)		(0.03)	0.01
Net income per share	$ 0.26	$ 2.07	$ 3.17	$ 3.94
Weighted average shares outstanding	42.4	42.7	42.5	42.8
Diluted:
Income from continuing operations	$ 0.28	$ 2.06	$ 3.17	$ 3.89
Net gain from discontinued operations	(0.02)		(0.03)
Net income per share	$ 0.26	$ 2.06	$ 3.14	$ 3.89
Weighted average shares outstanding	42.9	43.0	42.9	43.3