Annual report pursuant to Section 13 and 15(d)

Hedging Activities (Narrative) (Details)

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Hedging Activities (Narrative) (Details) (USD $)
0 Months Ended 1 Months Ended 2 Months Ended 3 Months Ended 4 Months Ended 5 Months Ended 10 Months Ended 12 Months Ended
Feb. 13, 2012
Mar. 31, 2009
bbl
Feb. 28, 2010
Jun. 30, 2009
bbl
Dec. 31, 2009
Aug. 31, 2009
Dec. 31, 2010
Dec. 31, 2011
Dec. 31, 2009
Hedging Activities [Abstract]                  
Expected to reclassify out of accumulated other comprehensive income in next 12 months               $ 1,576,000  
Gain on hedging effectiveness               25,000  
Production barrels per day 1,000   3,000   3,000 3,000 2,300 2,000  
Forward sales contract price     54.81   54.81 55.17 58.24    
Terminated forward sales contracts volume   3,000   3,000          
Terminated forward sales contracts amount   1,500,000   476,000          
Derivative contracts terminations amount included in oil and condensate sales                 $ 2,000,000
Delivered percentage of production under fixed price swaps               31.00%