- Level 3 Measurements of Derivative Commodity Instruments (Details) (USD $) In Thousands, unless otherwise specified			6 Months Ended		6 Months Ended			6 Months Ended			6 Months Ended			6 Months Ended			6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Oil Basis - WTS/WTI 2014	Jun. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Oil Basis - WTI/WTI 2014	Jun. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Oil Basis - WTI/WTI 2014 Minimum	Jun. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Oil Basis - WTI/WTI 2014 Maximum	Jun. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Liquids Swaps 2014	Jun. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Liquids Swaps 2014 Minimum	Jun. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Liquids Swaps 2014 Maximum	Jun. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - San Juan 2014	Jun. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - San Juan 2014 Minimum	Jun. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - San Juan 2014 Maximum	Jun. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - San Juan 2015	Jun. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - San Juan 2015 Minimum	Jun. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - San Juan 2015 Maximum	Jun. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - Permian 2014	Jun. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - Permian 2014 Minimum	Jun. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - Permian 2014 Maximum	Jun. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - Permian 2015
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Derivative assets	$ 1,147	$ 22,902	$ 1,119	$ 3,072			$ 91			$ 2,817			$ 579						$ 602
Derivative liabilities	$ (117,918)	$ (30,302)														$ (3,073)
Fair Value Inputs, Price Per Barrel			5.01		5.42	5.57
Fair Value Inputs, Price Per Gallon								0.74	0.97
Fair Value Inputs, Price Per Cubic Foot											0.03	0.07		0.01	0.12		0.06	0.07	0.13