Credit Agreements - Schedule of Debt Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2021	Sep. 30, 2020	Apr. 03, 2018
Debt Instrument [Line Items]
Principal	$ 825.0	$ 825.0
Debt Issuance Costs, Net	(6.7)	(7.1)
Debt, Net	818.3	817.9
Other short-term debt		5.2
Senior Term Loan
Debt Instrument [Line Items]
Principal	225.0	225.0
Debt Issuance Costs, Net	(0.3)	(0.3)
Debt, Net	224.7	224.7	$ 325.0
4.600% Senior Notes due May 2028
Debt Instrument [Line Items]
Principal	300.0	300.0
Debt Issuance Costs, Net	(2.8)	(3.0)
Debt, Net	297.2	297.0
3.100% Senior Notes due March 2030
Debt Instrument [Line Items]
Principal	300.0	300.0
Debt Issuance Costs, Net	(3.6)	(3.8)
Debt, Net	$ 296.4	$ 296.2

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 issuance costs. 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. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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