Annual report pursuant to Section 13 and 15(d)

Investment in Derivative Instruments (Details)

v3.20.2
Investment in Derivative Instruments (Details) - USD ($)
$ in Thousands
 12 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosures [Line Items]    
Realized Gain (Loss) $ (820) $ 5
Unrealized Gain (Loss) (1,900) (565)
Total Gain (Loss) (2,720) (560)
Net unrealized (loss) position (2,211) (311)
Accrued expense and other current liabilities - commodity swaps | Commodity swaps    
Derivative Instruments and Hedging Activities Disclosures [Line Items]    
Net unrealized (loss) position (183) 0
Other Noncurrent Liabilities | Commodity swaps    
Derivative Instruments and Hedging Activities Disclosures [Line Items]    
Net unrealized (loss) position (320) 0
Other Noncurrent Liabilities | Interest rate swaps    
Derivative Instruments and Hedging Activities Disclosures [Line Items]    
Net unrealized (loss) position (1,708) (311)
Cost of revenues    
Derivative Instruments and Hedging Activities Disclosures [Line Items]    
Realized Gain (Loss) (432) 0
Unrealized Gain (Loss) (503) 0
Total Gain (Loss) (935) 0
Interest expense, net    
Derivative Instruments and Hedging Activities Disclosures [Line Items]    
Realized Gain (Loss) (388) 5
Unrealized Gain (Loss) (1,397) (565)
Total Gain (Loss) $ (1,785) $ (560)