Annual report pursuant to Section 13 and 15(d)

Supplemental Information On Oil And Gas Exploration And Production Activities (Costs Incurred In Oil And Gas Property Acquisition And Development Activities) (Details)

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Supplemental Information On Oil And Gas Exploration And Production Activities (Costs Incurred In Oil And Gas Property Acquisition And Development Activities) (Details) (USD $)
12 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Supplemental Information On Oil And Gas Exploration And Production Activities [Abstract]      
Acquisition $ 119,522,000 $ 17,627,000 $ 1,885,000
Development of proved undeveloped properties 123,489,000 64,652,000 28,652,000
Exploratory 3,994,000   502,000
Recompletions 17,259,000 16,917,000 8,980,000
Capitalized asset retirement obligation 1,390,000 1,328,000 361,000
Total $ 265,654,000 $ 100,524,000 $ 40,380,000