Condensed Consolidated Statements of (Loss) Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Premiums and other revenue:
Earned premiums	$ 445.5	$ 451.5	$ 1,313.9	$ 1,303.7
Net investment income	42.0	40.2	79.0	116.9
Fee and other income	1.7	1.9	5.8	6.3
Net realized investment gains (losses):
Net realized investment (losses) gains	(5.7)	2.6	33.3	0.3
Change in fair value of equity securities	10.5	(8.8)	(12.0)	58.0
Credit losses on fixed maturity securities	(10.5)	0.0	(43.0)	0.0
Net realized investment (losses) gains	(5.7)	(6.2)	(21.7)	58.3
Total revenue	483.5	487.4	1,377.0	1,485.2
Expenses:
Losses and loss adjustment expenses	328.9	338.8	883.0	861.5
Underwriting, acquisition and insurance expenses	164.3	164.0	493.7	485.6
Other corporate expenses	0.4	3.7	6.2	11.7
Interest expense	6.8	7.5	21.3	25.3
Fee and other expense	0.9	1.2	3.1	3.8
Foreign currency exchange losses (gains)	11.6	(1.6)	15.0	(6.2)
Total expenses	512.9	513.6	1,422.3	1,381.7
(Loss) income before income taxes	(29.4)	(26.2)	(45.3)	103.5
Income tax provision (benefit)	0.2	(1.1)	9.5	8.6
Net (loss) income	(29.6)	(25.1)	(54.8)	94.9
Dividends on preferred shares	2.0	0.0	2.0	0.0
Net (loss) income attributable to common shareholders	$ (31.6)	$ (25.1)	$ (56.8)	$ 94.9
Net (loss) income per common share:
Basic (in dollars per share)	$ (0.91)	$ (0.73)	$ (1.64)	$ 2.78
Diluted (in dollars per share)	(0.91)	(0.73)	(1.64)	2.73
Dividends declared per common share (in dollars per share)	$ 0.31	$ 0.31	$ 0.93	$ 0.93
Weighted average common shares:
Basic (in shares)	34,667,266	34,299,999	34,590,659	34,161,016
Diluted (in shares)	34,667,266	34,299,999	34,590,659	34,769,622
Net realized investment gains (losses) before other-than-temporary impairment losses	$ (5.7)	$ (1.2)	$ (21.7)	$ 70.1
Other-than-temporary impairment losses recognized in earnings:
Other-than-temporary impairment losses on fixed maturities	0.0	(5.0)	0.0	(11.8)
Impairment losses recognized in earnings	0.0	(5.0)	0.0	(11.8)
Net realized investment (losses) gains	$ (5.7)	$ (6.2)	$ (21.7)	$ 58.3