Quarterly report pursuant to Section 13 or 15(d)

Investment in Derivative Instruments (Details)

v3.20.1
Investment in Derivative Instruments (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Mar. 31, 2020
Mar. 31, 2019
Mar. 31, 2020
Mar. 31, 2019
Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosures [Line Items]          
Realized Gain (Loss) $ (45) $ 9 $ (70) $ 5  
Unrealized Gain (Loss) (2,329) (106) (2,263) (331)  
Total Gain (Loss) (2,374) (97) (2,333) (326)  
Derivative liabilities, fair value (2,574)   (2,574)   $ (311)
Commodity swaps | Accrued Expense and Other Current Liabilities          
Derivative Instruments and Hedging Activities Disclosures [Line Items]          
Derivative liabilities, fair value (588)   (588)   0
Commodity swaps | Other Noncurrent Liabilities          
Derivative Instruments and Hedging Activities Disclosures [Line Items]          
Derivative liabilities, fair value (209)   (209)   0
Interest rate swaps | Other Noncurrent Liabilities          
Derivative Instruments and Hedging Activities Disclosures [Line Items]          
Derivative liabilities, fair value (1,777)   (1,777)   $ (311)
Cost of revenues          
Derivative Instruments and Hedging Activities Disclosures [Line Items]          
Realized Gain (Loss) (21) 0 (21) 0  
Unrealized Gain (Loss) 0 0 0 0  
Total Gain (Loss) (21) 0 (21) 0  
Other income (expense)          
Derivative Instruments and Hedging Activities Disclosures [Line Items]          
Realized Gain (Loss) 0 0 0 0  
Unrealized Gain (Loss) (797) 0 (797) 0  
Total Gain (Loss) (797) 0 (797) 0  
Interest expense, net          
Derivative Instruments and Hedging Activities Disclosures [Line Items]          
Realized Gain (Loss) (24) 9 (49) 5  
Unrealized Gain (Loss) (1,532) (106) (1,466) (331)  
Total Gain (Loss) $ (1,556) $ (97) $ (1,515) $ (326)