| **Asset Retirement Obligations**                      | 9 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
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| **Asset Retirement Obligation Disclosure [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| Asset Retirement Obligation Disclosure                | ASSET RETIREMENT OBLIGATIONSThe following table presents the changes in carrying amounts of the asset retirement obligations associated with our working interest in crude oil and natural gas properties:  Amount (in thousands)  Balance at December 31, 2012$62,563Obligations incurred with development activities337Accretion expense3,667Revisions in estimated cash flows251Obligations discharged with divestitures of properties and asset retirements(7,376)Balance at September 30, 201359,442Less: Liabilities held for sale (1)22,788Less: Current portion1,000Long-term portion$35,654  ______________(1)Represents asset retirement obligations related to our assets held for sale. See Note 12, Assets Held for Sale, Divestitures and Discontinued Operations and Note 15, Subsequent Events, for additional information regarding the potential sale of these properties. |

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| - Definition
The entire disclosure for an asset retirement obligation and the associated long-lived asset. An asset retirement obligation is a legal obligation associated with the disposal or retirement from service of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7569-110849
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