Consolidated Statements of Income (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Premiums and other revenue:
Earned premiums	$ 334.6	$ 325.7
Net investment income	20.8	23.3
Net realized investment and other gains	16.0	11.1
Total revenue	371.4	360.1
Expenses:
Losses and loss adjustment expenses	183.7	182.5
Underwriting, acquisition and insurance expenses	129.6	128.7
Interest expense	4.9	5.0
Fee expense, net	0.4	1.4
Foreign currency exchange (gain) loss	(9.6)	(0.2)
Total expenses	309.0	317.4
Income before income taxes	62.4	42.7
Provision for income taxes	3.6	2.5
Net income	58.8	40.2
Net income per common share:
Basic	$ 2.09	$ 1.38
Diluted	$ 2.05	$ 1.36
Dividend declared per common share	$ 0.20	$ 0.14
Weighted average common shares:
Basic	28,129,692	29,165,911
Diluted	28,677,379	29,663,090
Net realized investment and other gains before other-than-temporary impairment losses	16.5	11.1
Other-than-temporary impairment losses recognized in earnings:
Other-than-temporary impairment losses on fixed maturities	(0.4)	0
Other-than-temporary impairment losses on equity securities	(0.1)	0
Impairment losses recognized in earnings	(0.5)	0
Net realized investment and other gains	$ 16.0	$ 11.1