Debt - Summary Long-Term Debt Outstanding (Details) - USD ($) $ in Millions	Jun. 30, 2018	Sep. 30, 2017
Debt Instrument [Line Items]
Total long-term debt	$ 834.3	$ 823.7
Less: unamortized debt discount	(2.4)	(2.7)
Less: debt issuance costs	(15.4)	(16.7)
Less: current portion of long-term debt and capital lease obligations	(9.8)	(10.3)
Long-term debt and capital lease obligations, less current portion, net	806.7	794.0
Capital lease obligations
Debt Instrument [Line Items]
Total long-term debt	34.9	37.5
ABL Facility
Debt Instrument [Line Items]
Total long-term debt	157.4	139.3
Term Loan Facility
Debt Instrument [Line Items]
Total long-term debt	$ 642.0	$ 646.9

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, after accumulated amortization, of debt discount.

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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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Amount of long-term debt and capital lease obligation due after one year or beyond the normal operating cycle, if longer.

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