Derivative Financial Instruments - Schedule of Notional Amounts of Outstanding Forward Contracts (Details) - Foreign Exchange Forward - USD ($) $ in Thousands	Sep. 30, 2020	Sep. 30, 2019
Not Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	$ 512,462	$ 498,355
Canadian / U.S. Dollar | Not Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	6,847	9,408
Euro / U.S. Dollar | Not Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	390,673	308,282
Euro / U.S. Dollar | Designated as Hedging Instrument | Net Investment Hedging
Derivative [Line Items]
Notional amount	164,885	183,396
British Pound / U.S. Dollar | Not Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	6,328	3,756
Israeli Shekel / U.S. Dollar | Not Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	9,503	10,272
Japanese Yen / U.S. Dollar | Not Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	50,379	37,462
Swiss Franc / U.S. Dollar | Not Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	12,874	12,001
Swedish Krona / U.S. Dollar | Not Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	18,871	20,636
Singapore Dollar / U.S. Dollar | Not Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	3,281	34,585
Chinese Renminbi / U.S. Dollar | Not Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	5,415	52,466
All other | Not Designated as Hedging Instrument
Derivative [Line Items]
Notional amount	$ 8,291	$ 9,487