- Level 3 Measurements of Derivative Commodity Instruments (Details) (USD $)			9 Months Ended			9 Months Ended			9 Months Ended			9 Months Ended			9 Months Ended			9 Months Ended			9 Months Ended			9 Months Ended			3 Months Ended		9 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014 Level 3	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Oil Basis - WTS/WTI 2014	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Oil Basis - WTS/WTI 2015	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Oil Basis - WTS/WTI 2015 Minimum	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Oil Basis - WTS/WTI 2015 Maximum	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Oil Basis - WTI/WTI 2014	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Oil Basis - WTI/WTI 2014 Minimum	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Oil Basis - WTI/WTI 2014 Maximum	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Oil Basis - WTI/WTI 2015	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Oil Basis - WTI/WTI 2015 Minimum	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Oil Basis - WTI/WTI 2015 Maximum	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Liquids Swaps 2014	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Liquids Swaps 2014 Minimum	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Liquids Swaps 2014 Maximum	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - San Juan 2014	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - San Juan 2014 Minimum	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - San Juan 2014 Maximum	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - San Juan 2015	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - San Juan 2015 Minimum	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - San Juan 2015 Maximum	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - Permian 2014	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - Permian 2014 Minimum	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - Permian 2014 Maximum	Sep. 30, 2014 Discounted Cash Flow Valuation Technique Level 3 Natural Gas Basis - Permian 2015	Sep. 30, 2014 Commodity contracts	Sep. 30, 2013 Commodity contracts	Sep. 30, 2014 Commodity contracts	Sep. 30, 2013 Commodity contracts
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Gain (Loss) Recognized in other comprehensive income on derivatives																											$ 18,000	$ 42,000	$ 25,000	$ (6,669,000)
Sensitivity Analysis of Fair Value of 10 Percent Change in Commodity Prices			13,000,000
Sensitivity Analysis of Fair Value of Impact of 10 Percent Change in Mark-To-Market Derivative Contracts1			13,000,000
Derivative assets	35,953,000	22,902,000		1,115,000				2,736,000						1,600,000			4,946,000			5,097,000						1,924,000
Derivative liabilities	$ (1,448,000)	$ (30,302,000)			$ (181,000)						$ (1,979,000)												$ (372,000)
Fair Value Inputs, Price Per Barrel				6.62		4.20	4.24		7.07	7.18		4.60	4.97
Fair Value Inputs, Price Per Gallon															0.67	0.90
Fair Value Inputs, Price Per Cubic Foot																		0.05	0.12		0.09	0.10		0.09	0.10	0.13