Income Taxes - Statutes of limitations (Details)	12 Months Ended
	Sep. 30, 2016
Minimum
Income Taxes
Statutes of limitations, income tax returns filed by the Company, state and local	3 years
Statutes of limitations, income tax returns filed by non-U.S. subsidiaries	3 years
Maximum
Income Taxes
Statutes of limitations, income tax returns filed by the Company, state and local	4 years
Statutes of limitations, income tax returns filed by non-U.S. subsidiaries	10 years