Income Taxes (Details 1)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Effective Tax Rate Reconciliation
Statutory tax rate	35.00%	35.00%	35.00%
State and local income taxes	0.70%	0.60%	0.90%
Non-United States taxes	(9.30%)	(8.60%)	(7.90%)
Tax effect of foreign dividends	0.50%	0.10%	(0.20%)
Foreign currency transaction loss	(1.90%)	(0.80%)	0.00%
Share-based compensation	(2.80%)	0.00%	0.00%
Research and development tax credit	(0.60%)	(2.00%)	(0.60%)
Change in valuation allowances	0.10%	(0.60%)	(0.50%)
Domestic manufacturing deduction	(0.90%)	(1.20%)	(1.20%)
Adjustments for prior period tax matters	(0.40%)	0.40%	0.50%
Other	0.00%	(0.30%)	0.60%
Effective income tax rate	20.40%	22.60%	26.60%