Long-term Debt - Summary of Long-term Debt (Details) - USD ($) $ in Millions	Jun. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Finance leases	$ 46.5	$ 47.7
Total debt, net of unamortized discount and deferred financing costs	631.6	637.0
Less: Amounts due within one year	(293.2)	(284.7)
Total long-term debt, net of unamortized discount and deferred financing costs	$ 338.4	352.3
Secured debt
Debt Instrument [Line Items]
Effective interest rate (as a percent)	1.93%
Capital leases
Debt Instrument [Line Items]
Principal amount	$ 46.5	47.7
Term loan | Secured debt
Debt Instrument [Line Items]
Principal amount	319.4	328.1
Unamortized deferred financing costs	(1.5)	(1.8)
Senior Notes	317.9	326.3
2 1/4% Notes | Convertible Debt
Debt Instrument [Line Items]
Principal amount	300.0	300.0
Unamortized deferred financing costs	(32.8)	(37.0)
Total convertible senior notes	267.2	$ 263.0
Less: Amounts due within one year	$ (267.2)
Effective interest rate (as a percent)	5.80%	5.80%
Debt instrument interest rate stated percentage	2.25%