Income Taxes - Schedule of Unrecognized Tax Benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Unrecognized Tax Benefits [Roll Forward]
Unrecognized tax benefit, beginning of year	$ 50,742	$ 23,923	$ 21,166
Tax positions related to current year:
Additions	7,570	7,075	3,144
Tax positions related to prior years:
Additions	10,705	20,855	785
Reductions	(452)	0	(1,172)
Settlements	(3,530)	0	0
Statute expirations	0	(1,111)	0
Unrecognized tax benefit, end of year	$ 65,035	$ 50,742	$ 23,923