Subsequent Events (Details) - Subsequent Event
Aug. 02, 2018
bbl / d
Permian Basin Agreement  
Subsequent Event [Line Items]  
Supply commitment term 6 years
Permian Basin Agreement, Year One  
Subsequent Event [Line Items]  
Supply commitment, firm gross sales per day (in barrels) 20,000
Permian Basin Agreement, After Year One  
Subsequent Event [Line Items]  
Supply commitment, firm gross sales per day (in barrels) 30,000