Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized Tax Benefits, Beginning Balance	$ 10,897	$ 7,994	$ 5,834
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions	593	0	883
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	0	(385)	(65)
Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions	3,250	5,273	2,260
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities	0	(643)	0
Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations	(1,760)	(1,342)	(918)
Unrecognized Tax Benefits, Ending Balance	$ 12,980	$ 10,897	$ 7,994