Quarterly report pursuant to Section 13 or 15(d)

Basis of Presentation - Additional Information (Details)

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Basis of Presentation - Additional Information (Details)
9 Months Ended
Sep. 30, 2017
USD ($)
Loan
Dec. 31, 2016
USD ($)
Basis Of Presentation [Line Items]    
Number of loans for which maturities will be accelerated | Loan 2  
Outstanding obligation to secure financial assurances upon rescindment $ 0  
Deposit Into registry of court 49,500,000  
Oil and natural gas properties and equipment - full cost method, amount excluded from amortization 0 $ 0
Apache Corporation    
Basis Of Presentation [Line Items]    
Deposit Into registry of court $ 49,500,000