Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Deferred tax assets:
Loss and credit carryforwards	$ 19,122	$ 30,311
Compensation benefits	29,344	29,305
Operating lease liabilities	13,065	17,076
Other assets	14,744	16,711
Deferred tax assets, gross	76,275	93,403
Less: valuation allowance	(16,635)	(28,403)
Total deferred tax assets	59,640	65,000
Deferred tax liabilities:
Intangible assets	(14,263)	(10,518)
Deferred commission	(12,419)	(10,520)
Property and equipment	(327)	(487)
Operating lease right-of-use assets	(8,798)	(11,258)
Other liabilities	(12,030)	(11,668)
Total deferred tax liabilities	(47,837)	(44,451)
Deferred tax assets, net	$ 11,803	$ 20,549