|**Revenue Recognition Revenue Recognition (Tables)** | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
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|**Revenue from Contract with Customer [Abstract]**   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Disaggregation of Revenue [Table Text Block]         | Disaggregated Revenue.The following table presents crude oil, natural gas and NGLs sales disaggregated by commodity and operating region for the periods presented:Year Ended December 31,Revenue by Commodity and Operating Region202220212020(in thousands)Crude oilWattenberg Field$2,154,435$1,275,666$668,948Delaware Basin423,784255,135147,902Total2,578,2191,530,801816,850Natural gasWattenberg Field870,560458,870171,755Delaware Basin113,90960,7336,997Total984,469519,603178,752NGLsWattenberg Field614,260428,570128,126Delaware Basin119,73373,58428,827Total733,993502,154156,953Crude oil, natural gas and NGLsWattenberg Field3,639,2552,163,106968,829Delaware Basin657,426389,452183,726Total$4,296,681$2,552,558$1,152,555
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|Revenue by Commodity and Operating Region            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
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|Crude oil                                            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Wattenberg Field                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Delaware Basin                                       |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Total                                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Natural gas                                          |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Wattenberg Field                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Delaware Basin                                       |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Total                                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|NGLs                                                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Wattenberg Field                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Delaware Basin                                       |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Total                                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Crude oil, natural gas and NGLs                      |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Wattenberg Field                                     |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Delaware Basin                                       |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Total                                                |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|Contract with Customer, Asset and Liability          |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                

X- DefinitionTabular disclosure of receivable, contract asset, and contract liability from contract with customer. Includes, but is not limited to, change in contract asset and contract liability.
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