Summary of Significant Accounting Policies - Summary of Contract Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Contract with Customer, Liability [Roll Forward]
Beginning contract liability	$ 51,649	$ 65,460	$ 46,610
Revenue recognized from contract liabilities included in the beginning balance	48,642	63,207	43,777
Increases due to business combinations and cash received, net of amounts recognized in revenue during the period	60,948	49,396	62,627
Ending contract liability	$ 63,955	$ 51,649	$ 65,460