Business Combinations and Divestitures - Additional Information (Detail) $ in Thousands	12 Months Ended
	Sep. 30, 2022 USD ($) PartnershipUnit	Sep. 30, 2021 USD ($) PartnershipUnit	Jun. 30, 2022 USD ($)
Business Acquisition [Line Items]
Goodwill		$ 253,398	$ 256,471
Propane Assets
Business Acquisition [Line Items]
Cash proceeds from sale of assets		$ 6,100
Heating Oil Dealers
Business Acquisition [Line Items]
Number of businesses acquired | PartnershipUnit		3
Heating Oil Dealers | Scenario Forecast
Business Acquisition [Line Items]
Number of businesses acquired | PartnershipUnit	5
Aggregate purchase price partnership acquired	$ 15,600
Cash paid	13,100
Deferred liabilities	2,500
Aggregate purchase price allocation, intangible assets	7,300
Goodwill	3,100
Aggregate purchase price allocation, fixed assets	5,600
Gross purchase price increased (reduced) by working capital credits	$ (400)
Propane and Oil Dealers
Business Acquisition [Line Items]
Aggregate purchase price partnership acquired		$ 42,500
Cash paid		40,700
Deferred liabilities		1,800
Aggregate purchase price allocation, Goodwill and intangible assets		37,300
Aggregate purchase price allocation, fixed assets		6,200
Gross purchase price increased (reduced) by working capital credits		$ 1,000
Propane Dealers
Business Acquisition [Line Items]
Number of businesses acquired | PartnershipUnit		2