Derivative Financial Instruments (Derivative Instruments and Hedging Activities Disclosure) (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Derivative [Line Items]
Net realized and unrealized gain or (loss) (excluding the underlying foreign currency exposure being hedged)	$ (8,400)	$ (7,500)	$ 1,800
Gain or (Loss) Recognized in OCI-Effective Portion	5,251	1,445	(758)
Foreign Exchange Forward [Member] \| Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain or (Loss) Recognized in OCI-Effective Portion	187	1,652	(866)
Gain or (Loss) Reclassified from OCI into Income-Effective Portion	627	(552)	(524)
Gain or (Loss) Recognized-Ineffective Portion	0	21	(49)
Other Income (Expense) [Member] \| Foreign Exchange Forward [Member] \| Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Net realized and unrealized gain or (loss) (excluding the underlying foreign currency exposure being hedged)	(6,716)	(9,720)	870
Net Investment Hedging [Member] \| Foreign Exchange Forward [Member] \| Designated as Hedging Instrument [Member]
Derivative [Line Items]
Gain or (Loss) Recognized in OCI-Effective Portion	(2,925)	0	0
Other Comprehensive Income (Loss), Net Investment Hedge, Gain (Loss), Reclassification, before Tax	(7,630)	0	0
Net Investment Hedging [Member] \| Interest and Other Expense, Net [Member] \| Foreign Exchange Forward [Member] \| Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Excluded Component, Gain (Loss), Recognized in Earnings	$ 4,598	$ 0	$ 0

Amount of gain (loss) from excluded component of derivative hedge, recognized in earnings. Excludes recognition under systematic and rational method.

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The amount of net gains or losses on foreign currency cash flow hedges reclassified during the period to earnings from accumulated other comprehensive income upon the hedged transaction affecting earnings.

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The net gain (loss) during the reporting period due to ineffectiveness in foreign currency cash flow hedges. Recognized in earnings.

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Amount of gain (loss) recognized in earnings in the period from the increase (decrease) in fair value of foreign currency derivatives not designated as hedging instruments.

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Amount, before tax, of reclassification from accumulated other comprehensive income (AOCI) for gain (loss) from derivative designated and qualifying as net investment hedge.

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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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