v3.26.1
Segment Reporting - Summary of Segment Financial Information (Detail) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Segment Reporting Information [Line Items]        
Total sales $ 358,071 $ 305,618 $ 1,664,042 $ 1,536,726
Cost and expenses:        
General and administrative expenses 8,039 7,564 24,348 22,934
Finance charge income (1,877) (1,773) (4,030) (3,860)
Adjusted EBITDA (17,721) (10,583) 189,321 169,464
(Increase) decrease in the fair value of derivative instruments [1] 8,019 (603) (13,398) (11,962)
Depreciation and amortization expenses 8,333 9,197 25,373 26,012
Operating income (loss) (34,073) (19,177) 177,346 155,414
Interest expense, net (3,586) (3,639) (11,548) (11,114)
Amortization of debt issuance costs (259) (274) (786) (804)
Income (loss) before income taxes (37,918) (23,090) 165,012 143,496
Income tax expense (benefit) (9,929) (6,461) 48,928 41,330
Net income (loss) (27,989) (16,629) 116,084 102,166
Home heating oil and propane        
Segment Reporting Information [Line Items]        
Total sales 153,132 136,146 1,134,344 1,046,864
Motor fuel and other petroleum products        
Segment Reporting Information [Line Items]        
Total sales 113,877 80,012 270,436 233,858
Petroleum products        
Segment Reporting Information [Line Items]        
Total sales 267,009 216,158 1,404,780 1,280,722
Equipment installations        
Segment Reporting Information [Line Items]        
Total sales 32,745 33,317 100,691 100,082
Services        
Segment Reporting Information [Line Items]        
Total sales 58,317 56,143 158,571 155,922
Installations and services        
Segment Reporting Information [Line Items]        
Total sales 91,062 89,460 259,262 256,004
Cost of product        
Cost and expenses:        
Cost and expenses 195,199 144,521 876,174 800,170
Cost of installations        
Cost and expenses:        
Cost and expenses 25,802 27,306 80,013 81,878
Cost of service        
Cost and expenses:        
Cost and expenses 49,684 47,934 159,560 151,237
Delivery expenses        
Cost and expenses:        
Cost and expenses 22,070 22,546 100,375 94,884
Operations expenses        
Cost and expenses:        
Cost and expenses 19,407 18,175 59,561 57,483
Garage and plant expenses        
Cost and expenses:        
Cost and expenses 11,574 10,649 35,588 33,401
Sales and marketing expenses        
Cost and expenses:        
Cost and expenses 12,179 11,868 41,048 40,788
Customer service and credit expenses        
Cost and expenses:        
Cost and expenses 14,309 14,139 40,906 40,872
Insurance related expenses        
Cost and expenses:        
Cost and expenses 15,346 9,139 44,240 32,526
Information technology expenses        
Cost and expenses:        
Cost and expenses 4,060 4,133 11,938 11,841
Weather hedge contracts loss        
Cost and expenses:        
Cost and expenses $ 0 $ 0 $ 5,000 $ 3,108
[1] Represents the change in value of unrealized open positions and expired options.