Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended		12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Schedule Of Significant Accounting Policies [Line Items]
Cash, cash equivalents, and restricted cash	$ 19,097,000	$ 14,792,000			$ 57,161,000	$ 5,149,000
Cash and cash equivalents	18,847,000				56,911,000
Restricted cash	250,000				250,000
Benefit under weather hedge contract	4,000,000.0
Charge under weather hedge contract		$ 3,000,000.0
Accrued expenses and other current liabilities	133,713,000				127,286,000
Other long-term liabilities	26,998,000				25,001,000
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	16,700,000				16,700,000
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	$ 28,100,000				$ 29,000,000.0
Scenario Forecast
Schedule Of Significant Accounting Policies [Line Items]
Derivative maximum payout			$ 0	$ 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			$ 7,500,000	$ 12,500,000