Derivative Instruments - Notional Amounts Outstanding under Foreign Currency Contracts - Fair Value of Liabilities (Details) - Not Designated as Hedging Instrument - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 30, 2016
Derivative [Line Items]
Fair Value of Liabilities	$ (146)	$ (96)
Foreign Currency Contract, Buy Korean Won, Sell United States Dollar, Maturing October 2017
Derivative [Line Items]
Fair Value of Liabilities	(8)
Foreign Currency Contract, Buy United States Dollar, Sell Chinese Yuan, Maturing October 2017
Derivative [Line Items]
Fair Value of Liabilities	(2)
Foreign Currency Contract, Buy Euro, Sell United States Dollar, Maturing October 2017
Derivative [Line Items]
Fair Value of Liabilities	(62)
Foreign Currency Contract, Buy Euro, Sell British Pound, Maturing October 2017
Derivative [Line Items]
Fair Value of Liabilities	$ (74)
Foreign Currency Contract, Buy Euro, Sell United States Dollar, Maturing October 2016
Derivative [Line Items]
Fair Value of Liabilities		(40)
Foreign Currency Contract, Buy United States Dollar, Sell Chinese Yuan, Maturing October 2016
Derivative [Line Items]
Fair Value of Liabilities		(33)
Foreign Currency Contract, Buy Euro, Sell British Pound, Maturing October 2016
Derivative [Line Items]
Fair Value of Liabilities		$ (23)