Long-term Debt - Schedule of Debt (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Debt Instrument [Line Items]
Finance lease obligations	$ 23.5		$ 23.5		$ 23.6
Less: Debt issuance costs	(9.0)		(9.0)		(9.8)
Total debt	334.5		334.5		333.8
Less: Current portion of long-term debt	13.0		13.0		13.2
Long-term debt	321.5		321.5		320.6
Interest expense	13.3	$ 37.6	31.7	$ 77.0
Interest Paid, Capitalized, Investing Activities	22.9	40.6	41.9	77.8
Other Noncash Income (Expense)	1.7	5.2
Noncash interest expense, net			3.3	9.0
Financial assurance instruments
Debt Instrument [Line Items]
Interest expense	8.0	13.6	20.0	27.1
Indebtedness
Debt Instrument [Line Items]
Interest expense	5.3	$ 24.0	11.7	$ 49.9
Senior Notes | 3.250% Convertible Senior Notes due March 2028 (2028 Convertible Notes)
Debt Instrument [Line Items]
Long-term debt	$ 320.0		$ 320.0		$ 320.0
Stated interest rate	3.25%		3.25%