Acquisitions - Summary of Preliminary Valuations and Subject to Final Adjustment, Allocated to Intangible Assets (Detail) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2022	Sep. 30, 2021	Jan. 12, 2021
June Acquisition
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount			$ 109,700
Useful lives (in years)	15 years 2 months 12 days
Trade names and trademarks | June Acquisition
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount			17,000
Useful lives (in years)	20 years
Developed software / patented technology
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 87,000	$ 87,000
Developed software / patented technology | June Acquisition
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount			87,000
Useful lives (in years)	15 years
Non-competition / restrictive covenant agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 5,700	$ 6,300
Non-competition / restrictive covenant agreements | June Acquisition
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount			$ 5,700
Useful lives (in years)	3 years