Intangible Assets, Goodwill and Acquisitions - Schedule of Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 647.1	$ 856.0
Accumulated Amortization	(395.6)	(565.5)
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	639.6	622.8
Accumulated Amortization	$ (393.3)	(337.8)
Customer Relationships | Minimum
Finite Lived Intangible Assets [Line Items]
Useful Life	6 years
Customer Relationships | Maximum
Finite Lived Intangible Assets [Line Items]
Useful Life	21 years
Trademarks
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 4.8	230.9
Accumulated Amortization	$ (1.7)	(227.5)
Trademarks | Minimum
Finite Lived Intangible Assets [Line Items]
Useful Life	4 years
Trademarks | Maximum
Finite Lived Intangible Assets [Line Items]
Useful Life	12 years
Noncompete Agreements
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 2.7	2.3
Accumulated Amortization	$ (0.6)	$ (0.2)
Noncompete Agreements | Minimum
Finite Lived Intangible Assets [Line Items]
Useful Life	5 years