Fair Value Measurements (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Sep. 30, 2021
Assets:
Available-for-sale securities	$ 1,021,090	$ 3,679
Derivative Asset, Statement of Financial Position	Prepaid expenses and other current assets
Fair Value, Measurements, Recurring
Assets:
Available-for-sale securities	$ 1,021,090	3,679
Foreign exchange contracts	32	153
Net Investment Hedge	65,814
Total Assets	1,417,482	3,853
Liabilities:
Foreign exchange contracts	294	165
Acquisition-related contingent consideration		9,400
Total Liabilities	294	9,565
Fair Value, Measurements, Recurring | Cash equivalents
Assets:
Cash equivalents	330,546	21
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Recurring
Assets:
Available-for-sale securities	417,059
Total Assets	747,605	21
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fair Value, Measurements, Recurring | Cash equivalents
Assets:
Cash equivalents	330,546	21
Significant Other Observable Inputs (Level 2) | Fair Value, Measurements, Recurring
Assets:
Available-for-sale securities	604,031	3,679
Foreign exchange contracts	32	153
Net Investment Hedge	65,814
Total Assets	669,877	3,832
Liabilities:
Foreign exchange contracts	294	165
Total Liabilities	$ 294	165
Significant Unobservable Inputs (Level 3) | Fair Value, Measurements, Recurring
Liabilities:
Acquisition-related contingent consideration		9,400
Total Liabilities		$ 9,400