Derivative Commodity Instruments - Quantitative Disclosures About Fair Value (Details) (Income Approach Valuation Technique [Member], Level 3, USD $)	3 Months Ended
	Sep. 30, 2012
Natural Gas Basis - San Juan [Member] | 2012
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value as of June 30, 2012	$ 8,807,000
Natural Gas Basis - San Juan [Member] | 2012 | Minimum [Member]
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value Inputs, Price Per Cubic Foot	0.10
Natural Gas Basis - San Juan [Member] | 2012 | Maximum [Member]
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value Inputs, Price Per Cubic Foot	0.12
Natural Gas Basis - San Juan [Member] | 2013
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value as of June 30, 2012	27,968,000
Natural Gas Basis - San Juan [Member] | 2013 | Minimum [Member]
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value Inputs, Price Per Cubic Foot	0.14
Natural Gas Basis - San Juan [Member] | 2013 | Maximum [Member]
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value Inputs, Price Per Cubic Foot	0.15
Natural Gas Basis - San Juan [Member] | 2014
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value as of June 30, 2012	17,273,000
Natural Gas Basis - San Juan [Member] | 2014 | Minimum [Member]
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value Inputs, Price Per Cubic Foot	0.14
Natural Gas Basis - San Juan [Member] | 2014 | Maximum [Member]
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value Inputs, Price Per Cubic Foot	0.16
Natural Gas Basis - Permian [Member] | 2012
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value as of June 30, 2012	(634)
Fair Value Inputs, Price Per Cubic Foot	0.08
Natural Gas Basis - Permian [Member] | 2013
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value as of June 30, 2012	(1,221)
Fair Value Inputs, Price Per Cubic Foot	0.13
Natural Gas Basis - Permian [Member] | 2014
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value as of June 30, 2012	(2,132)
Natural Gas Basis - Permian [Member] | 2014 | Minimum [Member]
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value Inputs, Price Per Cubic Foot	0.13
Natural Gas Basis - Permian [Member] | 2014 | Maximum [Member]
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value Inputs, Price Per Cubic Foot	0.15
Oil Basis - WTS/WTI [Member] | 2012
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value as of June 30, 2012	14,000
Oil Basis - WTS/WTI [Member] | 2012 | Minimum [Member]
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value Inputs, Price Per Barrel	2.74
Oil Basis - WTS/WTI [Member] | 2012 | Maximum [Member]
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value Inputs, Price Per Barrel	2.81
Oil Basis - WTS/WTI [Member] | 2013
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value as of June 30, 2012	(5,085,000)
Fair Value Inputs, Price Per Barrel	1.59
WTI/WTI Basis Swaps [Member] | 2013
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value as of June 30, 2012	(379,000)
WTI/WTI Basis Swaps [Member] | 2013 | Minimum [Member]
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value Inputs, Price Per Barrel	0.75
WTI/WTI Basis Swaps [Member] | 2013 | Maximum [Member]
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value Inputs, Price Per Barrel	1.15
Natural Gas Liquids [Member] | 2012
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value as of June 30, 2012	3,594,000
Natural Gas Liquids [Member] | 2012 | Minimum [Member]
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value Inputs, Price Per Gallon	0.75
Natural Gas Liquids [Member] | 2012 | Maximum [Member]
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value Inputs, Price Per Gallon	0.89
Natural Gas Liquids [Member] | 2013
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value as of June 30, 2012	$ 9,076,000
Natural Gas Liquids [Member] | 2013 | Minimum [Member]
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value Inputs, Price Per Gallon	0.77
Natural Gas Liquids [Member] | 2013 | Maximum [Member]
Fair Value Inputs, Derivatives, Quantitative Information [Line Items]
Fair Value Inputs, Price Per Gallon	0.85