Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Sep. 30, 2023
Deferred tax assets:
Loss and credit carryforwards	$ 7,717	$ 12,309
Compensation benefits	32,093	30,490
Operating lease liabilities	7,881	9,396
Research and development costs	67,795	34,730
Other assets	18,241	17,327
Deferred tax assets, gross	133,727	104,252
Less: valuation allowance	0	(2,183)
Total deferred tax assets	133,727	102,069
Deferred tax liabilities:
Intangible assets	(7,812)	(7,226)
Deferred commission	(14,484)	(14,017)
Operating lease right-of-use assets	(7,240)	(6,228)
Other liabilities	(17,678)	(15,462)
Total deferred tax liabilities	(47,214)	(42,933)
Deferred tax assets, net	$ 86,513	$ 59,136