Annual report pursuant to Section 13 and 15(d)

Investment in Derivative Instruments - Balance Sheet Classification (Details)

v3.21.2
Investment in Derivative Instruments - Balance Sheet Classification (Details) - USD ($)
$ in Thousands
12 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Derivative Instruments and Hedging Activities Disclosures [Line Items]    
Net unrealized (loss) position $ (967) $ 2,211
Unrealized gain (loss) on cash flow hedging instruments (31)  
Prepaid Expenses and Other Current Assets | Commodity swap contracts    
Derivative Instruments and Hedging Activities Disclosures [Line Items]    
Derivative asset, fair value, gross assets 990 0
Other Assets | Commodity swap contracts    
Derivative Instruments and Hedging Activities Disclosures [Line Items]    
Derivative asset, fair value, gross assets 822 0
Accrued Expense and Other Current Liabilities | Commodity swap contracts    
Derivative Instruments and Hedging Activities Disclosures [Line Items]    
Derivative liability, fair value, gross liability 0 (183)
Accrued Expense and Other Current Liabilities | Interest rate swap contracts    
Derivative Instruments and Hedging Activities Disclosures [Line Items]    
Derivative liability, fair value, gross liability (97) 0
Other Noncurrent Liabilities | Commodity swap contracts    
Derivative Instruments and Hedging Activities Disclosures [Line Items]    
Derivative liability, fair value, gross liability 0 (320)
Other Noncurrent Liabilities | Interest rate swap contracts    
Derivative Instruments and Hedging Activities Disclosures [Line Items]    
Derivative liability, fair value, gross liability $ (748) $ (1,708)