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Summary of Significant Accounting Policies - Additional Information (Detail)
 12 Months Ended
Dec. 31, 2017
USD ($)
counterparty
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Mar. 31, 2017
USD ($)
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]        
Allowance for doubtful accounts $ 1,573,000 $ 1,309,000    
Capitalized interest costs 12,800,000 16,800,000 $ 18,600,000  
Amount of capitalized exploratory well costs that have been capitalized for period greater than one year $ 0      
Derivative, number of counterparties | counterparty 8      
Financing Receivable, Recorded Investment, Past Due $ 0      
Cumulative-effect adjustment for adoption of ASU 2016-09   4,724,000    
1 to 12 months        
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]        
Contractual commodity derivative volume, percent 110.00%      
13 to 24 months        
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]        
Contractual commodity derivative volume, percent 100.00%      
25 to 36 months        
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]        
Contractual commodity derivative volume, percent 75.00%      
37 to 60 months        
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]        
Contractual commodity derivative volume, percent 50.00%      
Restricted stock awards        
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]        
Restricted stock awards vesting period 3 years      
Building        
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]        
Estimated life of assets 20 years      
Salt water disposal facilities, natural gas processing plant and pipelines        
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]        
Estimated life of assets 30 years      
Furniture, software and equipment | Minimum        
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]        
Estimated life of assets 2 years      
Furniture, software and equipment | Maximum        
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]        
Estimated life of assets 7 years      
ASU 2016-09        
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]        
Stock-based compensation related to unrealized excess tax benefits       $ 10,600,000
Retained Earnings [Member]        
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]        
Cumulative-effect adjustment for adoption of ASU 2016-09   $ 2,684,000    
Retained Earnings [Member] | ASU 2016-09        
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]        
Cumulative-effect adjustment for adoption of ASU 2016-09 $ (2,700,000)