Derivative Instruments and Hedging Activities (Impact of Derivative Instruments on Earnings) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Derivative Instruments Gain Loss [Line Items]
Amount of (Income) Expense Recognized in Earnings on Derivative	$ (20,683)	$ (7,659)	$ 277	$ 3,590
Amount of (Gain) Loss Recognized in Accumulated OCI on Derivative	(8,892)	(45,298)	21,766	(34,004)
Amount of (Gain) Loss Reclassified from Accumulated OCI into Earnings	(20,683)	(7,262)	277	4,394
Floating-Rate Cross Currency Interest Rate Contract [Member] \| Derivatives in Fair Value Hedging Relationships [Member] \| Selling, General and Administrative Expenses [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of (Income) Expense Recognized in Earnings on Derivative	(1,660)	(2,043)	190	233
Amount of (Gain) Loss Recognized in Accumulated OCI on Derivative	(1,401)	(1,523)	262	2,075
Amount of (Gain) Loss Reclassified from Accumulated OCI into Earnings	(1,660)	(1,646)	190	1,037
Fixed-Rate Cross Currency Interest Rate Contract [Member] \| Cash Flow Hedging \| Selling, General and Administrative Expenses [Member]
Derivative Instruments Gain Loss [Line Items]
Amount of (Income) Expense Recognized in Earnings on Derivative	(19,023)	(5,598)	87	3,393
Amount of (Gain) Loss Recognized in Accumulated OCI on Derivative	(7,491)	(43,775)	21,504	(36,079)
Amount of (Gain) Loss Reclassified from Accumulated OCI into Earnings	$ (19,023)	(5,598)	$ 87	3,393
Treasury Lock \| Cash Flow Hedging \| Interest Expense
Derivative Instruments Gain Loss [Line Items]
Amount of (Income) Expense Recognized in Earnings on Derivative		(18)		(36)
Amount of (Gain) Loss Reclassified from Accumulated OCI into Earnings		$ (18)		$ (36)

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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