Intangible Assets - Indefinite-Lived Intangible Assets (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Sep. 30, 2017
Indefinite-lived Intangible Assets [Line Items]
Amortization of Intangible Assets	$ 0.6	$ 0.7	$ 1.7	$ 2.1
Gross Finite and Indefinite-Lived Intangible Assets	22.7		22.7		$ 22.7
Finite and Indefinited-Lived Accumulated Amortization and Impairment Charges	(12.1)		(12.1)		(10.4)
Intangible Assets, Net (Excluding Goodwill)	$ 10.6		$ 10.6		$ 12.3