Derivative Instruments and Hedging Activities (Impact of Derivative Instruments on Earnings) (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Derivative Instruments Gain Loss [Line Items]
Amount of (Income) Expense Recognized in Earnings on Derivative	$ 1,330	$ (32,484)	$ 1,467
Amount of (Gain) Loss Recognized in Accumulated OCI on Derivative	18,262	(47,759)	23,000
Amount of (Gain) Loss Reclassified from Accumulated OCI into Earnings	2,134	(31,446)	1,467
Floating-Rate Cross Currency Interest Rate Contract [Member] \| Derivatives in Fair Value Hedging Relationships [Member] \| Selling, General and Administrative Expense [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of (Income) Expense Recognized in Earnings on Derivative	4,592	(9,394)	472
Amount of (Gain) Loss Recognized in Accumulated OCI on Derivative	4,832	(8,317)	1,034
Amount of (Gain) Loss Reclassified from Accumulated OCI into Earnings	5,396	(8,356)	472
Fixed-Rate Cross Currency Interest Rate Contract [Member] \| Cash Flow Hedging [Member] \| Selling, General and Administrative Expense [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of (Income) Expense Recognized in Earnings on Derivative	(3,190)	(23,018)	1,067
Amount of (Gain) Loss Recognized in Accumulated OCI on Derivative	13,430	(39,442)	21,966
Amount of (Gain) Loss Reclassified from Accumulated OCI into Earnings	(3,190)	(23,018)	1,067
Treasury Lock [Member] \| Cash Flow Hedging [Member] \| Interest Expense [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of (Income) Expense Recognized in Earnings on Derivative	(72)	(72)	(72)
Amount of (Gain) Loss Reclassified from Accumulated OCI into Earnings	$ (72)	$ (72)	$ (72)

Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

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The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

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Amount after tax of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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