Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	6 Months Ended		12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2023	Sep. 30, 2021	Sep. 30, 2020
Schedule Of Significant Accounting Policies [Line Items]
Cash, cash equivalents, and restricted cash	$ 17,932,000	$ 9,133,000		$ 5,017,000	$ 57,161,000
Cash and cash equivalents	17,682,000			4,767,000
Restricted cash	250,000			250,000
Accrued expenses and other current liabilities	157,093,000			121,221,000
Other long-term liabilities	17,193,000			25,244,000
New England Teamsters & Trucking Industry Pension Fund
Schedule Of Significant Accounting Policies [Line Items]
Accrued expenses and other current liabilities	200,000			200,000
Other long-term liabilities	16,400,000			16,500,000
New England Teamsters & Trucking Industry Pension Fund | Significant Other Observable Inputs Level 2
Schedule Of Significant Accounting Policies [Line Items]
Multiemployer plan discounted withdrawal liability	23,500,000			$ 25,800,000
Financial Products Corporation | Delivery and branch expenses
Schedule Of Significant Accounting Policies [Line Items]
Delivery and branch expense reduced under weather hedge contract	$ 1,100,000	$ 3,400,000
Scenario Forecast
Schedule Of Significant Accounting Policies [Line Items]
Derivative maximum payout			$ 5,000,000.0
Maximum
Schedule Of Significant Accounting Policies [Line Items]
Cash equivalents, highly liquid investments maturity	3 months
Maximum | Scenario Forecast
Schedule Of Significant Accounting Policies [Line Items]
Derivative maximum receivable			$ 12,500,000