Quarterly report pursuant to Section 13 or 15(d)

Long-term debt, net - Narrative (Details)

v3.10.0.1
Long-term debt, net - Narrative (Details)
3 Months Ended 9 Months Ended 12 Months Ended
Mar. 28, 2018
USD ($)
redetermination
Dec. 08, 2017
USD ($)
Sep. 30, 2018
USD ($)
Sep. 30, 2017
USD ($)
Sep. 30, 2018
USD ($)
Sep. 30, 2017
USD ($)
Dec. 08, 2021
Dec. 08, 2020
Jun. 29, 2018
USD ($)
Line of Credit Facility [Line Items]                  
Available interim unscheduled redeterminations | redetermination 1                
Consecutive semiannual redeterminations | redetermination 2                
Amortization of debt issuance costs     $ 400,000 $ 100,000 $ 1,723,000 $ 168,000      
Credit Agreement | Revolving Credit Facility                  
Line of Credit Facility [Line Items]                  
Weighted-average interest rate (as a percent)     5.13%   5.13%        
Credit facility - maximum borrowing capacity $ 500,000,000                
Credit facility - borrowing base $ 150,000,000               $ 210,000,000
Credit Agreement | Rosehill Operating | Revolving Credit Facility                  
Line of Credit Facility [Line Items]                  
Working capital ratio, minimum     1.0   1.0        
Leverage ratio maximum     4.0   4.0        
Minimum | Base Rate | Credit Agreement | Revolving Credit Facility                  
Line of Credit Facility [Line Items]                  
Basis spread on variable rate (as a percent) 1.00%                
Minimum | London Interbank Offered Rate (LIBOR) | Credit Agreement | Revolving Credit Facility                  
Line of Credit Facility [Line Items]                  
Basis spread on variable rate (as a percent) 2.00%                
Maximum | Base Rate | Credit Agreement | Revolving Credit Facility                  
Line of Credit Facility [Line Items]                  
Basis spread on variable rate (as a percent) 2.00%                
Maximum | London Interbank Offered Rate (LIBOR) | Credit Agreement | Revolving Credit Facility                  
Line of Credit Facility [Line Items]                  
Basis spread on variable rate (as a percent) 3.00%                
Second Lien Notes | Senior Notes | Rosehill Operating                  
Line of Credit Facility [Line Items]                  
Leverage ratio maximum   4.00              
Aggregate principal amount   $ 100,000,000              
Stated interest rate of debt instrument (as a percent)   10.00%              
Redemption price (as a percent)   101.00%              
Second Lien Notes | Senior Notes | Forecast | Rosehill Operating                  
Line of Credit Facility [Line Items]                  
Redemption price (as a percent)             101.50% 103.00%  
Series B Preferred Stock | Credit Agreement | Rosehill Operating                  
Line of Credit Facility [Line Items]                  
Working capital ratio, minimum     2.5   2.5        
Leverage ratio maximum     4.0   4.0