Consolidated Statements Of Income (Loss) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Premiums and other revenue:
Earned premiums	$ 304.3	$ 270.9	$ 871.8	$ 804.0
Net investment income	28.9	30.0	90.3	96.3
Fee income, net	3.0	1.4	4.8	1.8
Net realized investment gains	8.3	3.9	18.7	37.7
Total revenue	344.5	306.2	985.6	939.8
Expenses:
Losses and loss adjustment expenses	186.3	199.6	527.9	664.4
Other reinsurance-related expenses	7.0	2.7	20.8	3.1
Underwriting, acquisition and insurance expenses	118.0	104.2	346.3	314.7
Interest expense	5.8	5.6	17.0	16.5
Foreign currency exchange loss (gain)	9.7	(1.9)	2.8	11.1
Total expenses	326.8	310.2	914.8	1,009.8
Income (loss) before income taxes	17.7	(4.0)	70.8	(70.0)
Provision for income taxes	4.3	6.8	13.8	13.3
Net (loss) income	13.4	(10.8)	57.0	(83.3)
Net income (loss) per common share:
Basic	$ 0.53	$ (0.39)	$ 2.22	$ (3.04)
Diluted	$ 0.52	$ (0.39)	$ 2.18	$ (3.04)
Dividend declared per common share:	$ 0.12	$ 0.12	$ 0.36	$ 0.36
Weighted average common shares:
Basic	25,227,194	27,237,788	25,694,761	27,374,953
Diluted	25,756,883	27,237,788	26,101,734	27,374,953
Realized investment gains before other-than-temporary impairment losses	9.4	5.1	20.7	38.9
Other-than-temporary impairment losses recognized in earnings
Other-than-temporary impairment losses on fixed maturities	(1.1)	(0.1)	(1.4)	(0.1)
Other-than-temporary impairment losses on equity securities	0	(1.1)	(0.6)	(1.1)
Non-credit portion of losses recognized in other comprehensive income (loss)	0	0	0	0
Impairment losses recognized in earnings	(1.1)	(1.2)	(2.0)	(1.2)
Net realized investment gains	$ 8.3	$ 3.9	$ 18.7	$ 37.7