Quarterly report pursuant to Section 13 or 15(d)

Subsequent Events - Additional Information (Details)

v3.8.0.1
Subsequent Events - Additional Information (Details) - Subsequent Event
$ in Millions
1 Months Ended
Apr. 05, 2018
USD ($)
May 03, 2018
USD ($)
Investor
Heidelberg Field Acquisition    
Subsequent Event [Line Items]    
Percentage of non-operated working interest acquired 9.375%  
Gross purchase price $ 31.1  
Letters of credit outstanding 9.4  
Amount of cash deposit required for issuance of letters of credit 4.7  
Letter of Credit | Heidelberg Field Acquisition    
Subsequent Event [Line Items]    
Revolving bank credit facility maximum lender commitment 5.0  
Minimum | Heidelberg Field Acquisition    
Subsequent Event [Line Items]    
Anti-hoarding provision, required cash $ 35.0  
JV Drilling Program    
Subsequent Event [Line Items]    
Number of additional third party investors committed to program | Investor   5
Commitment amount by investors   $ 297.6