Annual report pursuant to Section 13 and 15(d)

Asset Retirement Obligations - Schedule of Reconciliation of Asset Retirement Obligations (Details)

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Asset Retirement Obligations - Schedule of Reconciliation of Asset Retirement Obligations (Details) - USD ($)
$ in Thousands
12 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2019
Asset Retirement Obligation Disclosure [Abstract]      
Balance at beginning of year $ 0 $ 0  
Liabilities incurred 2,070 0  
Liabilities settled 0 0  
Liabilities assumed 718 0  
Accretion expense 0 0 $ 0
Balance at end of year $ 2,788 $ 0 $ 0