Business Combinations and Divestitures - Additional Information (Detail) $ in Thousands		6 Months Ended
	Oct. 25, 2022 USD ($)	Mar. 31, 2023 USD ($) PartnershipUnit	Mar. 31, 2022 USD ($) PartnershipUnit	Sep. 30, 2022 USD ($)
Business Acquisition [Line Items]
Goodwill		$ 254,354		$ 254,110
Heating Oil Dealers
Business Acquisition [Line Items]
Number of businesses acquired | PartnershipUnit		2	4
Aggregate purchase price partnership acquired		$ 1,200	$ 7,400
Cash and assuming		1,200	6,500
Liabilities			900
Aggregate purchase price allocation, intangible assets		1,700	4,900
Goodwill		200
Aggregate purchase price allocation, fixed assets		200	3,200
Gross purchase price increased (reduced) by working capital credits		$ 900	$ 700
Cash proceeds from sale of assets	$ 2,200