Derivative Financial Instruments - Schedule of Notional Amounts of Outstanding Forward Contracts and Options (Details) - Not Designated as Hedging Instrument - Foreign Exchange Forward Contract and Options - USD ($) $ in Thousands	Dec. 31, 2020	Sep. 30, 2020
Derivative [Line Items]
Notional amount	$ 666,777	$ 512,462
Canadian / U.S. Dollar
Derivative [Line Items]
Notional amount	5,696	6,847
Euro / U.S. Dollar
Derivative [Line Items]
Notional amount	569,595	390,673
British Pound / U.S. Dollar
Derivative [Line Items]
Notional amount	7,525	6,328
Israeli Shekel / U.S. Dollar
Derivative [Line Items]
Notional amount	9,468	9,503
Japanese Yen / U.S. Dollar
Derivative [Line Items]
Notional amount	29,174	50,379
Swiss Franc / U.S. Dollar
Derivative [Line Items]
Notional amount	8,969	12,874
Swedish Krona / U.S. Dollar
Derivative [Line Items]
Notional amount	9,189	18,871
Chinese Renminbi / U.S. Dollar
Derivative [Line Items]
Notional amount	11,698	5,415
Taiwanese Dollar / U.S. Dollar
Derivative [Line Items]
Notional amount	4,195	1,482
All other
Derivative [Line Items]
Notional amount	$ 11,268	$ 10,090