Impairment	12 Months Ended
Dec. 31, 2012
Impairment [Abstract]
Impairment	Impairment Gas Treating Plants. In conjunction with the Company’s substantial completion, in the fourth quarter of 2012, of the Century Plant, a CO₂ treatment plant in Pecos County, Texas (the “Century Plant”), and associated compression and pipeline facilities that it constructed pursuant to an agreement with Occidental Petroleum Corporation (“Occidental”), and resulting diversion of the Company’s high CO₂ natural gas production from its legacy gas treating plants to the Century Plant, the Company evaluated its legacy gas treating plants and CO₂compression facilities for impairment. Due to prevailing low natural gas prices, the Company’s natural gas production is not projected to reach the available treating capacity at the Century Plant. As such, the Company anticipates the use of its legacy gas treating plants and CO₂ compression facilities in west Texas will be limited, and accordingly, recorded a $79.3 million impairment of its gas treating plants and CO₂ compression facilities. Rigs. As a result of the Company’s agreement to sell the Permian Properties, the Company performed an impairment assessment of its drilling rigs as of December 31, 2012 by calculating the estimated future cash flows to be generated by the rigs and their related assets. As the undiscounted future cash flows were in excess of the assets’ carrying value, no impairment was indicated. Other Property, Plant and Equipment. The Company recorded a $1.3 million impairment in 2012 due to the write-off of certain software costs and a $2.8 million impairment in 2011 on certain natural gas compressors due to the determination that their future use was limited.

Impairment

Gas Treating Plants. In conjunction with the Company’s substantial completion, in the fourth quarter of 2012, of the Century Plant, a CO₂ treatment plant in Pecos County, Texas (the “Century Plant”), and associated compression and pipeline facilities that it constructed pursuant to an agreement with Occidental Petroleum Corporation (“Occidental”), and resulting diversion of the Company’s high CO₂ natural gas production from its legacy gas treating plants to the Century Plant, the Company evaluated its legacy gas treating plants and CO₂compression facilities for impairment. Due to prevailing low natural gas prices, the Company’s natural gas production is not projected to reach the available treating capacity at the Century Plant. As such, the Company anticipates the use of its legacy gas treating plants and CO₂ compression facilities in west Texas will be limited, and accordingly, recorded a $79.3 million impairment of its gas treating plants and CO₂ compression facilities.

Rigs. As a result of the Company’s agreement to sell the Permian Properties, the Company performed an impairment assessment of its drilling rigs as of December 31, 2012 by calculating the estimated future cash flows to be generated by the rigs and their related assets. As the undiscounted future cash flows were in excess of the assets’ carrying value, no impairment was indicated.

Other Property, Plant and Equipment. The Company recorded a $1.3 million impairment in 2012 due to the write-off of certain software costs and a $2.8 million impairment in 2011 on certain natural gas compressors due to the determination that their future use was limited.