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Summary of Significant Accounting Policies - Additional Information (Detail)
3 Months Ended
Mar. 31, 2018
USD ($)
Segment
Mar. 31, 2017
USD ($)
Dec. 31, 2017
USD ($)
Summary Of Significant Accounting Policies [Line Items]      
Accounts receivable $ 113,208,000   $ 77,609,000
Capitalized interest expense $ 500,000 $ 400,000  
Revenue recognition payment receivable period 1 month    
Revenue, practical expedient, nondisclosure of transaction price allocation to remaining performance obligation description true    
Accounts receivable attributable to revenue contracts with customers $ 51,300,000   52,900,000
Depreciation, depletion and amortization $ 31,156,000 $ 26,189,000  
Asset retirement obligations credit adjusted discount rates 10.33% 10.33%  
Operating lease expiration year 2024    
Number of operating segment | Segment 1    
Oil and Gas Properties [Member]      
Summary Of Significant Accounting Policies [Line Items]      
Depreciation, depletion and amortization $ 30,700,000 $ 25,700,000  
Other property and equipment [Member]      
Summary Of Significant Accounting Policies [Line Items]      
Depreciation $ 500,000 500,000  
Other property and equipment [Member] | Minimum [Member]      
Summary Of Significant Accounting Policies [Line Items]      
Property and equipment, expected lives 5 years    
Other property and equipment [Member] | Maximum [Member]      
Summary Of Significant Accounting Policies [Line Items]      
Property and equipment, expected lives 40 years    
Proved Oil And Gas Properties [Member]      
Summary Of Significant Accounting Policies [Line Items]      
Impairment of oil and gas properties $ 0 0  
Unproved Oil And Gas Properties [Member]      
Summary Of Significant Accounting Policies [Line Items]      
Impairment of oil and gas properties 6,700,000 $ 4,100,000  
Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]      
Summary Of Significant Accounting Policies [Line Items]      
Fair value of commodity derivative contracts (8,900,000)   (5,100,000)
Unbilled Revenues [Member]      
Summary Of Significant Accounting Policies [Line Items]      
Accounts receivable $ 51,300,000   $ 52,900,000