v3.26.1
Long-Term Debt and Bank Facility Borrowings - Additional Information (Detail) - USD ($)
9 Months Ended
Sep. 27, 2024
Jun. 30, 2026
Jun. 30, 2025
Sep. 30, 2025
Debt Instrument [Line Items]        
Additional loan repayments   $ 15,750,000 $ 15,750,000  
Hedging positions and payable amounts secured under credit facility       $ 1,300,000
Letters of credit issued and outstanding   3,000,000   5,100,000
Long-term debt, fair value [1]   173,250,000   189,000,000
Availability under credit agreement   $ 229,900,000   $ 165,000,000
Term Loan        
Debt Instrument [Line Items]        
Debt instrument, effective interest rate   6.70%   7.10%
Long-term debt, fair value [1],[2]   $ 173,250,000   $ 189,000,000
Revolving Credit Facility        
Debt Instrument [Line Items]        
Debt instrument, effective interest rate   5.90%   6.40%
Revolving credit facility outstanding   $ 0   $ 0
Credit Agreement        
Debt Instrument [Line Items]        
Non Seasonal maximum borrowing capacity under revolving credit facility $ 400,000,000      
Maximum borrowing capacity (heating season December to April) under revolving credit facility 475,000,000      
Issuance of line of credit for working capital purposes $ 25,000,000      
Senior secured term loan maturity date Sep. 27, 2029      
Facility size that can be increased additional without consulting bank group   200,000,000    
Facility size that can be increased without consulting bank group   200,000,000    
Term loan annual payment percentage 25.00%      
Commitment fee on the unused portion of the facility from December through April 0.30%      
Commitment fee on the unused portion of the facility from May through November 0.20%      
Minimum fixed charge coverage ratio 110.00%      
Credit Agreement | Quarterly        
Debt Instrument [Line Items]        
Term loan periodic payment $ 5,300,000      
Credit Agreement | Term Loan        
Debt Instrument [Line Items]        
Outstanding term loan $ 210,000,000      
Senior secured term loan maturity period 5 years      
Maximum | Credit Agreement        
Debt Instrument [Line Items]        
Availability percentage to maximum facility size 12.50%      
Maximum facility size $ 35,000,000 $ 29,100,000    
Senior secured leverage ratio during quarters ending June or September 300.00%      
Senior secured leverage ratio during quarters ending December or March 550.00%      
Maximum | Credit Agreement | Annually        
Debt Instrument [Line Items]        
Term loan periodic payment $ 4,000,000      
[1] The face amount of the Company’s variable rate long-term debt approximates fair value.
[2] Carrying amounts are net of unamortized debt issuance costs of $0.7 million as of June 30, 2026, and $0.9 million as of September 30, 2025