Annual report pursuant to Section 13 and 15(d)

Accounts Receivable and Major Customers - Summary of Accounts Receivable (Detail)

v3.10.0.1
Accounts Receivable and Major Customers - Summary of Accounts Receivable (Detail) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Sep. 30, 2018
Dec. 31, 2018
Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Customers   $ 59,030 $ 39,106
Joint interest partners   6,404 32,493
Other   640 584
Accounts Receivable, Gross, Current, Total   66,074 72,183
Less: Allowance for doubtful accounts   (36) (2,362)
Accounts receivable, net of allowance for doubtful accounts   66,038 $ 69,821
Oil and Gas, Refining and Marketing [Member]      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Revenue from contract with customer $ 523    
Calculated under Revenue Guidance in Effect before Topic 606 [Member]      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Cost of Goods and Services Sold   20,982  
Net Income (Loss) Available to Common Stockholders, Basic   224,785  
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Oil and Gas, Exploration and Production [Member]      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Revenue from contract with customer   402,485  
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Oil and Condensate [Member]      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Revenue from contract with customer   23,429  
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Natural Gas, Production [Member]      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Revenue from contract with customer   15,972  
Calculated under Revenue Guidance in Effect before Topic 606 [Member] | Oil and Gas, Refining and Marketing [Member]      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Revenue from contract with customer   523  
Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member]      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Cost of Goods and Services Sold   (2,356)  
Net Income (Loss) Available to Common Stockholders, Basic   0  
Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Oil and Gas, Exploration and Production [Member]      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Revenue from contract with customer   0  
Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Oil and Condensate [Member]      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Revenue from contract with customer   (2,356)  
Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Natural Gas, Production [Member]      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Revenue from contract with customer   0  
Accounting Standards Update 2014-09 [Member] | Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Oil and Gas, Refining and Marketing [Member]      
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]      
Revenue from contract with customer   $ 0