Debt - Carrying Amounts of Debt (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Long-term debt	$ 800.0
Unamortized discount and issuance costs	(3.4)	$ (2.6)
Total debt	796.6	552.0
Less: Current maturities	(17.5)	(32.3)
Total long-term debt	779.1	519.7
Line of Credit \| Senior Revolver
Debt Instrument [Line Items]
Long-term debt	100.0	70.0
Borrowing availability	349.5
Line of Credit \| Senior Term Loan
Debt Instrument [Line Items]
Long-term debt	700.0	$ 484.6
Line of Credit \| Letter of Credit
Debt Instrument [Line Items]
Long-term debt	$ 0.5

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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Amount of unamortized debt discount (premium) and debt issuance costs.

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Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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