Earnings (Loss) per Common Share (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Earnings (Loss) per Common Share
Loss from continuing operations, basic	$ (2.5)	$ (68.6)	$ (108.3)
Loss from continuing operations, diluted	(2.5)	(68.6)	(108.3)
Income from discontinued operations, basic		839.1	122.7
Income from discontinued operations, diluted		839.1	122.7
Net (loss) income, basic	(2.5)	770.5	14.4
Net (loss) income, diluted	$ (2.5)	$ 770.5	$ 14.4
Basic weighted-average shares	83,930,984	82,720,934	81,561,707
Diluted weighted-average shares	83,930,984	82,720,934	81,561,707
Basic and diluted loss per common share - continuing operations
Basic (in dollars per share)	$ (0.03)	$ (0.83)	$ (1.33)
Diluted (in dollars per share)	(0.03)	(0.83)	(1.33)
Basic and diluted earnings per common share - discontinued operations
Basic (in dollars per share)		10.14	1.51
Diluted (in dollars per share)		10.14	1.51
Basic and diluted (loss) earnings per common share
Basic (in dollars per share)	(0.03)	9.31	0.18
Diluted (in dollars per share)	$ (0.03)	$ 9.31	$ 0.18