Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements of Financial Instruments (Details)

v3.10.0.1
Fair Value Measurements of Financial Instruments (Details)
$ in Thousands
Sep. 30, 2018
USD ($)
Counterparty
Dec. 31, 2017
USD ($)
Fair Value Measurements of Financial Instruments    
Number of bank counterparties for company's commodity derivative contracts | Counterparty 4  
Recurring | Total | Commodity Derivatives    
Derivative Assets:    
Total assets $ 1,977 $ 4,384
Derivative Liabilities:    
Total liabilities (19,548) (7,617)
Recurring | Total | Commodity Derivatives | Swaps | Oil    
Derivative Liabilities:    
Total liabilities (7,110) (3,679)
Recurring | Total | Commodity Derivatives | Swaps | Natural gas    
Derivative Assets:    
Total assets 69 821
Derivative Liabilities:    
Total liabilities (361)  
Recurring | Total | Commodity Derivatives | Collars | Oil    
Derivative Assets:    
Total assets 1,477 952
Derivative Liabilities:    
Total liabilities (11,722) (2,605)
Recurring | Total | Commodity Derivatives | Collars | Natural gas    
Derivative Assets:    
Total assets 431 2,611
Derivative Liabilities:    
Total liabilities (355) (1,333)
Recurring | Significant Other Observable Inputs (Level 2) | Commodity Derivatives    
Derivative Assets:    
Total assets 1,977 4,384
Derivative Liabilities:    
Total liabilities (19,548) (7,617)
Recurring | Significant Other Observable Inputs (Level 2) | Commodity Derivatives | Swaps | Oil    
Derivative Liabilities:    
Total liabilities (7,110) (3,679)
Recurring | Significant Other Observable Inputs (Level 2) | Commodity Derivatives | Swaps | Natural gas    
Derivative Assets:    
Total assets 69 821
Derivative Liabilities:    
Total liabilities (361)  
Recurring | Significant Other Observable Inputs (Level 2) | Commodity Derivatives | Collars | Oil    
Derivative Assets:    
Total assets 1,477 952
Derivative Liabilities:    
Total liabilities (11,722) (2,605)
Recurring | Significant Other Observable Inputs (Level 2) | Commodity Derivatives | Collars | Natural gas    
Derivative Assets:    
Total assets 431 2,611
Derivative Liabilities:    
Total liabilities $ (355) $ (1,333)