Condensed Consolidated Statements of (Loss) Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Premiums and other revenue:
Earned premiums	$ 451.5	$ 446.9	$ 1,303.7	$ 1,279.3
Net investment income	40.2	34.5	116.9	103.7
Fee and other income	1.9	3.3	6.3	7.2
Net realized investment (losses) gains:
Net realized investment gains	2.6	9.7	0.3	31.1
Change in fair value of equity securities	(8.8)	4.5	58.0	(22.1)
Net realized investment (losses) gains	(6.2)	14.2	58.3	9.0
Total revenue	487.4	498.9	1,485.2	1,399.2
Expenses:
Losses and loss adjustment expenses	338.8	277.5	861.5	760.2
Underwriting, acquisition and insurance expenses	167.7	168.0	497.3	485.0
Interest expense	7.5	7.9	25.3	23.4
Fee and other expense	1.2	1.9	3.8	5.5
Foreign currency exchange gains	(1.6)	(1.7)	(6.2)	(2.3)
Total expenses	513.6	453.6	1,381.7	1,271.8
(Loss) income before income taxes	(26.2)	45.3	103.5	127.4
Income tax (benefit) provision	(1.1)	4.7	8.6	20.2
Net (loss) income	$ (25.1)	$ 40.6	$ 94.9	$ 107.2
Net (loss) income per common share:
Basic (in dollars per share)	$ (0.73)	$ 1.20	$ 2.78	$ 3.16
Diluted (in dollars per share)	(0.73)	1.17	2.73	3.09
Dividend declared per common share (in dollars per share)	$ 0.31	$ 0.27	$ 0.93	$ 0.81
Weighted average common shares:
Basic (in shares)	34,299,999	33,956,695	34,161,016	33,921,632
Diluted (in shares)	34,299,999	34,656,328	34,769,622	34,688,843
Net realized investment (losses) gains before other-than-temporary impairment losses	$ (1.2)	$ 14.2	$ 70.1	$ 10.9
Other-than-temporary impairment losses recognized in earnings:
Other-than-temporary impairment losses on fixed maturities	(5.0)	0.0	(11.8)	(1.9)
Impairment losses recognized in earnings	$ (5.0)	$ 0.0	$ (11.8)	$ (1.9)