Derivative Instruments and Hedging Activities - Derivatives Designated as Hedging Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Derivatives Designated as Hedging Instruments
Derivatives not designated as hedging instruments	$ (1,051)	$ 2,731	$ 1,935
Probable loss on counterparty defaults	0
Selling, general and administrative expenses
Derivatives Designated as Hedging Instruments
Amount of Gain or (Loss) Recognized in Income on Derivatives, Foreign Exchange Contracts	(1,100)	2,700	1,900
Foreign exchange contracts
Credit-risk-related Contingent Features
Aggregate fair value of all foreign exchange contracts held in a liability position	300
Foreign exchange contracts | Selling, general and administrative expenses
Derivatives Designated as Hedging Instruments
Amount of Gain or (Loss) Recognized in Income on Derivatives, Foreign Exchange Contracts	$ (1,051)	$ 2,731	$ 1,935