Goodwill and Intangible Assets - Components of Identifiable Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Finite-Lived Intangible Assets [Line Items]
Cost	$ 331,606	$ 331,325
Accumulated Amortization	145,072	119,002
Net Book Value	186,534	212,323
Patents
Finite-Lived Intangible Assets [Line Items]
Cost	1,242	1,235
Accumulated Amortization	1,002	798
Net Book Value	240	437
Completed Technology
Finite-Lived Intangible Assets [Line Items]
Cost	75,527	62,646
Accumulated Amortization	32,383	24,082
Net Book Value	43,144	38,564
Trademarks and Trade Names
Finite-Lived Intangible Assets [Line Items]
Cost	424	25,569
Accumulated Amortization	33	9,122
Net Book Value	391	16,447
Noncompete Agreements
Finite-Lived Intangible Assets [Line Items]
Cost	681
Accumulated Amortization	249
Net Book Value	432
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Cost	253,486	241,630
Accumulated Amortization	111,159	84,758
Net Book Value	142,327	156,872
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Cost	246	245
Accumulated Amortization	$ 246	242
Net Book Value		$ 3