Company's Derivatives on Consolidated Financial Statements of Operations (Details) - Foreign Currency Forward Contracts - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amount of (Loss) Gain Recognized in Income	$ (106)	$ 50	$ 2,698
Other Income (Expense)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amount of (Loss) Gain Recognized in Income	$ (106)	$ 50	$ 2,698