Fair Value Measurements (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities	$ 1,263,784	$ 3,679
Derivative Asset, Statement of Financial Position	Prepaid expenses and other current assets
Fair Value, Recurring
Assets, Fair Value Disclosure [Abstract]
Cash equivalents		21
Available-for-sale securities	$ 1,263,782	3,679
Foreign exchange contracts	634	153
Net Investment Hedge	124,789
Total Assets	1,764,009
Liabilities, Fair Value Disclosure [Abstract]
Foreign exchange contracts	230	165
Acquisition-related contingent consideration		9,400
Total Liabilities	230	9,565
Fair Value, Recurring | Cash Equivalents
Assets, Fair Value Disclosure [Abstract]
Cash equivalents	374,804
Fair Value, Recurring | Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure [Abstract]
Cash equivalents		21
Available-for-sale securities	651,800
Total Assets	1,025,855
Fair Value, Recurring | Fair Value, Inputs, Level 1 | Cash Equivalents
Assets, Fair Value Disclosure [Abstract]
Cash equivalents	374,055
Fair Value, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities	611,982	3,679
Foreign exchange contracts	634	153
Net Investment Hedge	124,789
Total Assets	738,154
Liabilities, Fair Value Disclosure [Abstract]
Foreign exchange contracts	230	165
Total Liabilities	230	165
Fair Value, Recurring | Fair Value, Inputs, Level 2 | Cash Equivalents
Assets, Fair Value Disclosure [Abstract]
Cash equivalents	$ 749
Fair Value, Recurring | Fair Value, Inputs, Level 3
Liabilities, Fair Value Disclosure [Abstract]
Acquisition-related contingent consideration		9,400
Total Liabilities		$ 9,400