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Description of Operations and Significant Accounting Policies - Additional Information (Detail)
12 Months Ended
Dec. 31, 2018
Well
Partnership
Trust
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
Property, Plant and Equipment [Line Items]      
Number of wells under non-operating interests | Well 800    
Number of limited partnerships | Partnership 3    
Number of business income trusts | Trust 2    
Valuation allowance | $   $ 0 $ 0
Maximum maturity period of cash and cash equivalents 90 days    
Minimum [Member]      
Property, Plant and Equipment [Line Items]      
Number of wells operating by the company 1,400    
Depreciation period of equipment 5 years    
Maximum [Member]      
Property, Plant and Equipment [Line Items]      
Depreciation period of equipment 10 years