Income Taxes - Schedule of Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Income Tax Disclosure [Abstract]
Income tax computed at statutory rate	$ 8,579	$ 33,408	$ 38,356
State income taxes, net of federal benefit	2,223	3,273	2,874
Permanent differences	4,261	9,140	2,037
Stock-based compensation	611	1,055	179
Tax credits	(20,253)	(27,918)	(20,287)
Deferred rate change	(343)	53	665
Other, net	184	(101)	134
Total (benefit) expense from income taxes	$ (4,738)	$ 18,910	$ 23,958