Income Taxes - Summary of Income (Loss) Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Income Tax Disclosure [Abstract]
Domestic	$ (49,193)	$ 97,460	$ 41,199
Foreign	381,759	299,638	350,556
Income before income taxes	$ 332,566	$ 397,098	$ 391,755

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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+ Details