Condensed Consolidated Statements of (Loss) Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Premiums and other revenue:
Earned premiums	$ 433.4	$ 431.7	$ 868.4	$ 852.2
Net investment income	1.5	42.8	37.0	76.7
Fee and other income	2.0	2.1	4.1	4.4
Net realized investment gains (losses):
Net realized investment gains (losses)	11.1	(0.6)	39.0	(2.3)
Change in fair value of equity securities	16.8	12.6	(22.5)	66.8
Credit losses on fixed maturity securities	(7.8)	0.0	(32.5)	0.0
Net realized investment gains (losses)	20.1	12.0	(16.0)	64.5
Total revenue	457.0	488.6	893.5	997.8
Expenses:
Losses and loss adjustment expenses	273.2	284.8	554.1	522.7
Underwriting, acquisition and insurance expenses	161.4	161.4	329.4	321.6
Other corporate expenses	2.5	7.5	5.8	8.0
Interest expense	6.8	9.3	14.5	17.8
Fee and other expense	1.0	1.3	2.2	2.6
Foreign currency exchange losses (gains)	6.4	(5.3)	3.4	(4.6)
Total expenses	451.3	459.0	909.4	868.1
Income (loss) before income taxes	5.7	29.6	(15.9)	129.7
Income tax provision	12.1	0.8	9.3	9.7
Net (loss) income	$ (6.4)	$ 28.8	$ (25.2)	$ 120.0
Net (loss) income per common share:
Basic (in dollars per share)	$ (0.18)	$ 0.84	$ (0.73)	$ 3.52
Diluted (in dollars per share)	(0.18)	0.83	(0.73)	3.45
Dividends declared per common share (in dollars per share)	$ 0.31	$ 0.31	$ 0.62	$ 0.62
Weighted average common shares:
Basic (in shares)	34,634,353	34,195,250	34,551,935	34,090,372
Diluted (in shares)	34,634,353	34,779,991	34,551,935	34,759,548
Net realized investment gains (losses) before other-than-temporary impairment losses	$ 20.1	$ 14.5	$ (16.0)	$ 71.3
Other-than-temporary impairment losses recognized in earnings:
Other-than-temporary impairment losses on fixed maturities	0.0	(2.5)	0.0	(6.8)
Impairment losses recognized in earnings	0.0	(2.5)	0.0	(6.8)
Net realized investment gains (losses)	$ 11.1	$ (0.6)	$ 39.0	$ (2.3)