Long-term Debt - Summary of Long-term Debt (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Finance leases	$ 46.1	$ 47.7
Total debt, net of unamortized discount and deferred financing costs	629.1	637.0
Less: Amounts due within one year	(297.7)	(284.7)
Total long-term debt, net of unamortized discount and deferred financing costs	$ 331.4	352.3
Secured debt
Debt Instrument [Line Items]
Effective interest rate (as a percent)	1.90%
Capital leases
Debt Instrument [Line Items]
Principal amount	$ 46.1	47.7
Term loan \| Secured debt
Debt Instrument [Line Items]
Principal amount	315.0	328.1
Unamortized deferred financing costs	(1.4)	(1.8)
Senior Notes	313.6	326.3
2 1/4% Notes \| Convertible Debt
Debt Instrument [Line Items]
Principal amount	300.0	300.0
Unamortized deferred financing costs	(30.6)	(37.0)
Total convertible senior notes	269.4	$ 263.0
Less: Amounts due within one year	$ (269.4)
Effective interest rate (as a percent)	5.80%	5.80%
Debt instrument interest rate stated percentage	2.25%

Including the current and noncurrent portions, carrying amount of debt identified as being convertible into another form of financial instrument (typically the entity's common stock) as of the balance sheet date, which originally required full repayment more than twelve months after issuance or greater than the normal operating cycle of the company.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Present value of lessee's discounted obligation for lease payments from finance lease.

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