Derivative Financial Instruments - Company's Derivatives on Consolidated Financial Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Foreign Currency Forward Contracts | Other Income (Expense)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Amount of (Loss) Gain Recognized in Income	$ 363	$ 217	$ 265	$ 639