Income Taxes - Components of Income Tax Provision (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Federal	$ (599)	$ (4,826)	$ (14,247)
State	1,528	607	(867)
Foreign	9,757	4,627	15,484
Total current income tax provision	10,686	408	370
Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract]
Federal	(18,684)	(815)	(11,469)
State	(402)	(180)	(2,283)
Foreign	(9,150)	1,937	(6,718)
Total deferred income tax provision (benefit)	(28,236)	942	(20,470)
Income tax (benefit) expense	$ (17,550)	$ 1,350	$ (20,100)