|**Transactions with Affiliates and Other Related Parties (Tables)** | 3 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
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|**Related Party Transactions [Abstract]**                           |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Schedule of Related Party Transactions                              | We provide certain well operating and administrative services for PDCM. Amounts billed to PDCM for these services were$2.3 millionand$3.4 millionfor the three months endedMarch 31, 2014andMarch 31, 2013, respectively. Our statements of operations include only our proportionate share of these billings. The following table presents the statement of operations line item in which our proportionate share is recorded and the amount for each of the periods presented:Three Months Ended March 31,Condensed consolidated statement of operations line item20142013(in thousands)Production costs$605$1,066Exploration expense—105General and administrative expense556515
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|Condensed consolidated statement of operations line item            |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
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|Production costs                                                    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|Exploration expense                                                 |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    
|General and administrative expense                                  |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    

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