Derivative Instruments and Hedging Activities (Impact of Derivative Instruments on Earnings) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Income) Expense Recognized in Earnings on Derivative	$ (7,659)	$ (11,045)	$ 3,590	$ (19,008)
Amount of (Gain) Loss Recognized in Accumulated OCI on Derivative	(45,298)	(9,609)	(34,004)	(28,172)
Amount of (Gain) Loss Reclassified from Accumulated OCI into Earnings	(7,262)	(10,895)	4,394	(18,721)
Floating-Rate Cross Currency Interest Rate Contract [Member] \| Selling, General and Administrative Expenses [Member] \| Derivatives in Fair Value Hedging Relationships [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Income) Expense Recognized in Earnings on Derivative	(2,043)	(3,033)	233	(5,422)
Amount of (Gain) Loss Recognized in Accumulated OCI on Derivative	(1,523)	(3,030)	2,075	(5,535)
Amount of (Gain) Loss Reclassified from Accumulated OCI into Earnings	(1,646)	(2,883)	1,037	(5,135)
Fixed-Rate Cross Currency Interest Rate Contract [Member] \| Selling, General and Administrative Expenses [Member] \| Derivatives in Cash Flow Hedging Relationships [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Income) Expense Recognized in Earnings on Derivative	(5,598)	(7,994)	3,393	(13,550)
Amount of (Gain) Loss Recognized in Accumulated OCI on Derivative	(43,775)	(6,579)	(36,079)	(22,637)
Amount of (Gain) Loss Reclassified from Accumulated OCI into Earnings	(5,598)	(7,994)	3,393	(13,550)
Treasury Lock [Member] \| Interest Expense [Member] \| Derivatives in Cash Flow Hedging Relationships [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Income) Expense Recognized in Earnings on Derivative	(18)	(18)	(36)	(36)
Amount of (Gain) Loss Reclassified from Accumulated OCI into Earnings	$ (18)	$ (18)	$ (36)	$ (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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