Fair Value Measurements - Summary of Changes in Fair Value of Contingent Consideration Liabilities Which Reflect Level 3 Inputs (Details) - Contingent Consideration Liabilities [Member] - Level 3 [Member] - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]
Beginning Balance	$ 86,059	$ 15,207
Additions from business acquisitions	613	68,680
Settlement of contingent consideration liabilities	(2,250)	(4,000)
Change in fair value and net present value of contingency	219	1,047
Ending Balance	$ 84,641	$ 80,934