Goodwill and Other Intangible Assets - Summary of Gross Carrying Amounts and Accumulated Amortization of Intangible Assets by Major Class (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Mar. 31, 2022	Sep. 30, 2021
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 199,534	$ 201,223
Accumulated Amortization	(183,587)	(175,875)
Net Carrying Amount	15,947	25,348
Customer Relationships
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	109,202	110,485
Accumulated Amortization	(93,979)	(88,638)
Net Carrying Amount	$ 15,223	$ 21,847
Weighted Average Remaining Life (Years)	1 year 10 months 24 days	2 years 2 months 12 days
Technology and Patents
Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 90,332	$ 90,738
Accumulated Amortization	(89,608)	(87,237)
Net Carrying Amount	$ 724	$ 3,501
Weighted Average Remaining Life (Years)	1 year 8 months 12 days	10 months 24 days