Long-Term Debt - Scheduled Maturities of Long-Term Debt (Details) - USD ($) $ in Millions	Jun. 30, 2021	Sep. 30, 2020
Debt Disclosure [Abstract]
2021	$ 2.6
2022	10.4
2023	10.4
2024	150.3
2025 and thereafter	972.1
Total long-term debt	1,145.8
Less: Current portion of long-term debt	10.4	$ 12.3
Less: Original issue discount	1.7
Less: Financing costs	11.9
Total long-term debt, net	$ 1,121.8	$ 1,127.5

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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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Amount of debt discount to be amortized after one year or the normal operating cycle, if longer.

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

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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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