Goodwill and Intangible Assets - Components of Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Sep. 30, 2021
Finite-Lived Intangible Assets [Line Items]
Cost	$ 331,015	$ 331,606
Accumulated Amortization	160,508	145,072
Net Book Value	170,507	186,534
Patents
Finite-Lived Intangible Assets [Line Items]
Cost	1,234	1,242
Accumulated Amortization	1,055	1,002
Net Book Value	179	240
Completed Technology
Finite-Lived Intangible Assets [Line Items]
Cost	75,373	75,527
Accumulated Amortization	35,833	32,383
Net Book Value	39,540	43,144
Trademarks and Trade Names
Finite-Lived Intangible Assets [Line Items]
Cost	424	424
Accumulated Amortization	47	33
Net Book Value	377	391
Noncompete Agreements
Finite-Lived Intangible Assets [Line Items]
Cost	681	681
Accumulated Amortization	344	249
Net Book Value	337	432
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Cost	253,063	253,486
Accumulated Amortization	122,989	111,159
Net Book Value	130,074	142,327
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Cost	240	246
Accumulated Amortization	$ 240	$ 246