Intangible Assets - Acquired Intangible Assets (Details) - USD ($) $ in Millions	Sep. 30, 2016	Sep. 30, 2015
Acquired Finite-Lived Intangible Assets [Line Items]
Gross	$ 130.0	$ 129.1
Accumulated Amortization	(55.2)	(47.5)
Net	74.8	81.6
Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Gross	80.4	79.6
Accumulated Amortization	(19.5)	(15.5)
Net	60.9	64.1
Patents and technology
Acquired Finite-Lived Intangible Assets [Line Items]
Gross	46.4	46.4
Accumulated Amortization	(34.2)	(30.6)
Net	12.2	15.8
Other
Acquired Finite-Lived Intangible Assets [Line Items]
Gross	3.2	3.1
Accumulated Amortization	(1.5)	(1.4)
Net	$ 1.7	$ 1.7