Restructuring and Other Costs, Net - Schedule of Accrual Activity Relating to Restructuring Charges (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Restructuring Cost And Reserve [Line Items]
Beginning Balance	$ 5,154	$ 5,035	$ 2,702
Restructuring and other costs, net	11,917	8,965	5,092
Non-cash adjustment	2,814	(4,708)	1,809
Cash payments	(18,305)	(4,082)	(4,507)
Foreign exchange impact on ending balance	2	(56)	(61)
Ending Balance	1,582	5,154	5,035
Personnel
Restructuring Cost And Reserve [Line Items]
Beginning Balance	1,277	1,620	764
Restructuring and other costs, net	7,778	1,676	1,689
Cash payments	(8,498)	(2,021)	(839)
Foreign exchange impact on ending balance	(8)	2	6
Ending Balance	549	1,277	1,620
Facilities
Restructuring Cost And Reserve [Line Items]
Beginning Balance	1,600	1,881	10
Restructuring and other costs, net	460	673	1,394
Non-cash adjustment	(486)	(708)	1,809
Cash payments	(551)	(188)	(1,265)
Foreign exchange impact on ending balance	10	(58)	(67)
Ending Balance	1,033	1,600	1,881
Restructuring Subtotal
Restructuring Cost And Reserve [Line Items]
Beginning Balance	2,877	3,501	774
Restructuring and other costs, net	8,238	2,349	3,083
Non-cash adjustment	(486)	(708)	1,809
Cash payments	(9,049)	(2,209)	(2,104)
Foreign exchange impact on ending balance	2	(56)	(61)
Ending Balance	1,582	2,877	3,501
Other
Restructuring Cost And Reserve [Line Items]
Beginning Balance	2,277	1,534	1,928
Restructuring and other costs, net	3,679	6,616	2,009
Non-cash adjustment	3,300	(4,000)
Cash payments	$ (9,256)	(1,873)	(2,403)
Ending Balance		$ 2,277	$ 1,534