Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Income Taxes [Line Items]
Foreign pretax earnings	$ 150,800	$ 172,700	$ 136,000
Current foreign tax expense related to foreign tax withholdings	14,600	12,300	9,500
Unrecognized tax benefits	19,879	$ 13,849	$ 12,980	$ 10,897
Unrecognized tax benefits that would impact the effective tax rate if recognized	18,600
Unrecognized tax benefits, accrued interest	$ 1,700
Effective income tax rate	21.00%
Unremitted earnings of foreign subsidiaries	$ 82,600
Deferred Tax Liabilities, Undistributed Foreign Earnings	2,800
U.S. Federal
Income Taxes [Line Items]
Net operating loss carryforwards	2,800
California Franchise Tax Board | Research Tax Credit Carryforward
Income Taxes [Line Items]
Excess state research credit	$ 7,100