Acquisitions - Narrative (Detail) - USD ($) $ in Thousands			3 Months Ended			6 Months Ended
	Apr. 01, 2021	Jan. 12, 2021	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2021
Business Acquisition [Line Items]
Gain (loss) from investments in unconsolidated affiliates			$ 0		$ 6,910	$ 0	$ 5,505
Goodwill			109,579			$ 109,579		$ 110,612
Reduction in accrued expenses from change in fair value of liability			$ (1,300)
Equity Method Investment, Realized Gain (Loss) on Disposal				$ (6,900)
June Acquisition
Business Acquisition [Line Items]
Fair value of equity interest		$ 24,144
Increase in goodwill		9,800
Goodwill		53,193
Goodwill, expected tax deductible amount		0
Deferred tax liabilities		24,500
Useful lives (in years)						15 years 2 months 12 days
June Acquisition | Loss Gain From Investments In Unconsolidated Affiliates
Business Acquisition [Line Items]
Gain (loss) from investments in unconsolidated affiliates				$ (1,400)
June Acquisition | Selling, General and Administrative Expenses
Business Acquisition [Line Items]
Acquisition related costs		$ 1,200
RMC Acquisition
Business Acquisition [Line Items]
Increase in goodwill	$ 27,100
Goodwill	27,120
RMC Acquisition | Selling, General and Administrative Expenses
Business Acquisition [Line Items]
Net deferred tax assets	400
RMC Acquisition | Contractual Rights
Business Acquisition [Line Items]
Acquisition related costs	$ 300
Useful lives (in years)	3 years 3 months 18 days