Derivative Financial Instruments (Notional Amounts of Outstanding Forward Contracts (Details) - Foreign Exchange Forward [Member] - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 405,956	$ 318,519
Not Designated as Hedging Instrument [Member] | Canadian / U.S. Dollar
Derivative [Line Items]
Derivative, Notional Amount	7,334	12,809
Not Designated as Hedging Instrument [Member] | Euro / U.S. Dollar
Derivative [Line Items]
Derivative, Notional Amount	297,730	244,000
Not Designated as Hedging Instrument [Member] | British Pound / U.S. Dollar
Derivative [Line Items]
Derivative, Notional Amount	7,074	907
Not Designated as Hedging Instrument [Member] | Israeli Sheqel / U.S. Dollar
Derivative [Line Items]
Derivative, Notional Amount	9,778	8,820
Not Designated as Hedging Instrument [Member] | Japanese Yen / Euro
Derivative [Line Items]
Derivative, Notional Amount	0	17,694
Not Designated as Hedging Instrument [Member] | Japanese Yen / U.S. Dollar
Derivative [Line Items]
Derivative, Notional Amount	37,456	3,198
Not Designated as Hedging Instrument [Member] | Swiss Franc / U.S. Dollar
Derivative [Line Items]
Derivative, Notional Amount	11,944	605
Not Designated as Hedging Instrument [Member] | Swiss Franc / Euro
Derivative [Line Items]
Derivative, Notional Amount	0	7,157
Not Designated as Hedging Instrument [Member] | SEK / U.S. Dollar
Derivative [Line Items]
Derivative, Notional Amount	18,207	4,627
Not Designated as Hedging Instrument [Member] | Chinese Yuan offshore / Euro
Derivative [Line Items]
Derivative, Notional Amount	0	10,423
Not Designated as Hedging Instrument [Member] | Singapore Dollar / U.S. Dollar
Derivative [Line Items]
Derivative, Notional Amount	1,314	1,186
Not Designated as Hedging Instrument [Member] | China, Yuan Renminbi
Derivative [Line Items]
Derivative, Notional Amount	9,010	0
Not Designated as Hedging Instrument [Member] | All other
Derivative [Line Items]
Derivative, Notional Amount	6,109	7,093
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member]
Derivative [Line Items]
Derivative, Notional Amount	12,396	101,597
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Euro / U.S. Dollar
Derivative [Line Items]
Derivative, Notional Amount	8,495	64,831
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Japanese Yen / U.S. Dollar
Derivative [Line Items]
Derivative, Notional Amount	2,193	22,675
Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | SEK / U.S. Dollar
Derivative [Line Items]
Derivative, Notional Amount	$ 1,708	$ 14,091