Supplemental Information on Oil and Gas Exploration and Production Activities (Unaudited) (Details Textual) (USD $)	12 Months Ended		1 Months Ended	12 Months Ended
	Dec. 31, 2011 MMBbls Bcf Wells	Dec. 31, 2010 lb Wells	Dec. 31, 2011 Cat Canyon And West Cat Canyon [Member]	Dec. 31, 2011 Cat Canyon And West Cat Canyon [Member]	Dec. 31, 2011 Equity Companies [Member]	Dec. 31, 2011 U.S. [Member] Crude Oil Per Barrel [Member] Consolidated Subsidiary [Member]	Dec. 31, 2010 U.S. [Member] Crude Oil Per Barrel [Member] Consolidated Subsidiary [Member]	Dec. 31, 2011 U.S. [Member] Crude Oil Per Barrel [Member] Equity Companies [Member]	Dec. 31, 2010 U.S. [Member] Crude Oil Per Barrel [Member] Equity Companies [Member]	Dec. 31, 2011 U.S. [Member] Liquid Natural Gas Per Barrel [Member] Consolidated Subsidiary [Member]	Dec. 31, 2010 U.S. [Member] Liquid Natural Gas Per Barrel [Member] Consolidated Subsidiary [Member]	Dec. 31, 2011 U.S. [Member] Liquid Natural Gas Per Barrel [Member] Equity Companies [Member]	Dec. 31, 2010 U.S. [Member] Liquid Natural Gas Per Barrel [Member] Equity Companies [Member]	Dec. 31, 2011 U.S. [Member] Natural Gas, Per Thousand Cubic Feet [Member] Consolidated Subsidiary [Member]	Dec. 31, 2010 U.S. [Member] Natural Gas, Per Thousand Cubic Feet [Member] Consolidated Subsidiary [Member]	Dec. 31, 2011 U.S. [Member] Natural Gas, Per Thousand Cubic Feet [Member] Equity Companies [Member]	Dec. 31, 2010 U.S. [Member] Natural Gas, Per Thousand Cubic Feet [Member] Equity Companies [Member]	Dec. 31, 2011 Canada [Member] Natural Gas, Per Thousand Cubic Feet [Member] Consolidated Subsidiary [Member]	Dec. 31, 2010 Canada [Member] Natural Gas, Per Thousand Cubic Feet [Member] Consolidated Subsidiary [Member]	Dec. 31, 2010 Canada [Member] Natural Gas, Per Thousand Cubic Feet [Member] Equity Companies [Member]	Dec. 31, 2011 Colombia [Member] Crude Oil Per Barrel [Member] Consolidated Subsidiary [Member]	Dec. 31, 2010 Colombia [Member] Crude Oil Per Barrel [Member] Consolidated Subsidiary [Member]	Dec. 31, 2010 Colombia [Member] Crude Oil Per Barrel [Member] Equity Companies [Member]
Average Sales Price and Production Costs Per Unit of Production [Line Items]
Average Sales Prices						96.19	61.12	0.00	70.60	57.71	36.43	0.00	39.04	4.12	3.72	0.00	4.53	3.85	2.81	2.78	9.45	78.21	76.00
Percentage of working capital interest sold			25.00%	25.00%
Cash proceeds from affiliate, from sale of oil and gas assets	$ 89,200,000		$ 71,600,000
Percentage of purchase of working interest				25.00%
Transportation Cost From Pipeline Commitments					24,200,000
Supplemental Information On Oil And Gas Exploration And Production Activities Unaudited (Textual) [Abstract]
Acquisitions of properties	360.4
Drilling of non-proved properties	122.2
Portion of negative revisions due to proved undeveloped reserves being reclassified to non-proved	384
Proved reserves	4.8
Decrease in proved reserves	9.5
Pressure Base Per Inch for Natural Gas Volume (Pound)		14.73
Cash distribution from the sale of oil and gas assets	$ 142,984,000
Proved reserves	20.8
Productive wells		273
Number wells to be produced		22
Average production costs Per Barrel of oil equivalents BOE		65.64