Net Income Per Unrestricted Share - Reconciliation of Numerator and Denominator Used in Calculation (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Schedule of Basic and Diluted Earnings Per Share [Line Items]
Net Income (Loss)	$ (76.2)	$ (75.3)	$ (245.7)	$ (14.7)
Dilutive Effect on Income of Equity-based Compensation Equivalent Shares	0.0	0.0	0.0	0.0
Diluted Net Income (Loss) Attributed to Unrestricted Shares	$ (76.2)	$ (75.3)	$ (245.7)	$ (14.7)
Weighted-Average Unrestricted Shares Outstanding (in shares)	63,852,800	63,628,100	63,804,400	64,469,900
Equity-based Compensation Equivalent Shares (in shares)	0	0	0	0
Weighted-Average Unrestricted Shares and Equivalent Shares Outstanding Assuming Dilution (in shares)	63,852,800	63,628,100	63,804,400	64,469,900
Basic (in dollars per share)	$ (1.19)	$ (1.18)	$ (3.85)	$ (0.23)
Diluted (in dollars per share)	$ (1.19)	$ (1.18)	$ (3.85)	$ (0.23)
Common Stock
Schedule of Basic and Diluted Earnings Per Share [Line Items]
Net Income (Loss)	$ (76.2)	$ (75.3)	$ (245.7)	$ (14.7)
Participating Awards
Schedule of Basic and Diluted Earnings Per Share [Line Items]
Net Income (Loss)	$ 0.0	$ 0.0	$ 0.0	$ 0.0