Oil and Gas Reserve Information Unaudited (Details Textual)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Oil and Gas Reserve Information - Unaudited: (Additional) (Textual)
Acquisition of additional working interested in pyrenees project	15.00%
Replacement of assumption due to revision of oil and gas reporting requirements		replaced the single-day year-end pricing with a twelve-month average pricing assumption
Average 12-month oil prices net of differentials	100.97	77.68	58.95
Average 12-month gas prices net of differentials	4.74	4.46	3.49
Annual discount rate for discounting future cash flows	10.00%