Fair Value Measurements - Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities	$ 559,914			$ 1,263,784
Derivative Asset, Statement of Financial Position	Prepaid expenses and other current assets			Prepaid expenses and other current assets
Liabilities, Fair Value Disclosure [Abstract]
Contingent consideration liability	$ 0	$ 1,400	$ 18,500
Fair Value, Recurring
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities	559,914			$ 1,263,782
Foreign exchange contracts				634
Net investment hedge	984			124,789
Total Assets	1,150,224			1,764,009
Liabilities, Fair Value Disclosure [Abstract]
Foreign exchange contracts	428			230
Total Liabilities	428			230
Fair Value, Recurring | Cash Equivalents
Assets, Fair Value Disclosure [Abstract]
Cash equivalents	589,326			374,804
Fair Value, Recurring | Fair Value, Inputs, Level 1
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities	127,592			651,800
Total Assets	716,918			1,025,855
Fair Value, Recurring | Fair Value, Inputs, Level 1 | Cash Equivalents
Assets, Fair Value Disclosure [Abstract]
Cash equivalents	589,326			374,055
Fair Value, Recurring | Fair Value, Inputs, Level 2
Assets, Fair Value Disclosure [Abstract]
Available-for-sale securities	432,322			611,982
Foreign exchange contracts				634
Net investment hedge	984			124,789
Total Assets	433,306			738,154
Liabilities, Fair Value Disclosure [Abstract]
Foreign exchange contracts	428			230
Total Liabilities	$ 428			230
Fair Value, Recurring | Fair Value, Inputs, Level 2 | Cash Equivalents
Assets, Fair Value Disclosure [Abstract]
Cash equivalents				$ 749