Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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+ Details

Revenue Recognition - Summary of Disaggregation of Revenue by Major Sources (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Disaggregation Of Revenue [Line Items]
Total sales	$ 358,071	$ 305,618	$ 1,664,042	$ 1,536,726
Home heating oil and propane
Disaggregation Of Revenue [Line Items]
Total sales	153,132	136,146	1,134,344	1,046,864
Other petroleum products
Disaggregation Of Revenue [Line Items]
Total sales	113,877	80,012	270,436	233,858
Petroleum products
Disaggregation Of Revenue [Line Items]
Total sales	267,009	216,158	1,404,780	1,280,722
Equipment installations
Disaggregation Of Revenue [Line Items]
Total sales	32,745	33,317	100,691	100,082
Equipment maintenance service contracts
Disaggregation Of Revenue [Line Items]
Total sales	36,862	36,888	97,283	98,863
Billable call services
Disaggregation Of Revenue [Line Items]
Total sales	21,455	19,255	61,288	57,059
Installations and services
Disaggregation Of Revenue [Line Items]
Total sales	$ 91,062	$ 89,460	$ 259,262	$ 256,004