Consolidated Statements Of Income (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
REVENUES
Premiums	$ 1,035.6	$ 761.7
Net investment income	68.8	60.4
Net realized investment gains (losses):
Net realized gains from sales and other	5.0	4.7
Net other-than-temporary impairment losses on investments recognized in earnings	(1.9)	(1.4)
Total net realized investment gains	3.1	3.3
Fees and other income	14.3	8.4
Total revenues	1,121.8	833.8
LOSSES AND EXPENSES
Losses and loss adjustment expenses	661.4	511.0
Policy acquisition expenses	228.1	162.5
Interest expense	16.2	10.4
Other operating expenses	145.3	112.4
Total losses and expenses	1,051.0	796.3
Income before income taxes	70.8	37.5
Income tax expense (benefit):
Current	39.0	4.1
Deferred	(18.9)	5.5
Total income tax expense	20.1	9.6
Income from continuing operations	50.7	27.9
Net gain (loss) from discontinued operations (net of income tax benefit of $0.1 and $0.3)	(1.0)	1.4
Net income	$ 49.7	$ 29.3
Basic
Income from continuing operations	$ 1.13	$ 0.62
Net gain (loss) from discontinued operations	$ (0.02)	$ 0.03
Net income per share	$ 1.11	$ 0.65
Weighted average shares outstanding	44.9	45.3
Diluted
Income from continuing operations	$ 1.11	$ 0.61
Net gain (loss) from discontinued operations	$ (0.02)	$ 0.03
Net income per share	$ 1.09	$ 0.64
Weighted average shares outstanding	45.5	46.0