Business Separation Costs - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Business separation costs	$ 30.2	$ 12.0
Materials Technologies [Member]
Restructuring Cost and Reserve [Line Items]
Business separation costs	$ 30.2	$ 12.0