Derivative Instruments (Commodity Derivatives) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012 MMBTU
Derivative [Line Items]
Fair Value Asset/(Liability)	$ 418,300
Natural Gas Fixed Price Swaps [Member]
Derivative [Line Items]
Fair Value Asset/(Liability)	226,200
Natural Gas Put Option [Member]
Derivative [Line Items]
Fair Value Asset/(Liability)	192,100
Production Period Ending December 31, 2013 [Member] | Natural Gas Fixed Price Swaps [Member]
Derivative [Line Items]
Volumes (mmbtu)	705,600
Average Fixed Price (per mmbtu)	3.798
Fair Value Asset/(Liability)	179,900
Production Period Ending December 31, 2013 [Member] | Natural Gas Put Option [Member]
Derivative [Line Items]
Volumes (mmbtu)	149,900
Average Strike (per mmbtu)	3.45
Fair Value Asset/(Liability)	37,800
Production Period Ending December 31, 2014 [Member] | Natural Gas Fixed Price Swaps [Member]
Derivative [Line Items]
Volumes (mmbtu)	540,000
Average Fixed Price (per mmbtu)	4.110
Fair Value Asset/(Liability)	42,700
Production Period Ending December 31, 2014 [Member] | Natural Gas Put Option [Member]
Derivative [Line Items]
Volumes (mmbtu)	124,900
Average Strike (per mmbtu)	3.80
Fair Value Asset/(Liability)	47,400
Production Period Ending December 31, 2015 [Member] | Natural Gas Fixed Price Swaps [Member]
Derivative [Line Items]
Volumes (mmbtu)	288,000
Average Fixed Price (per mmbtu)	4.224
Fair Value Asset/(Liability)	(1,400)
Production Period Ending December 31, 2015 [Member] | Natural Gas Put Option [Member]
Derivative [Line Items]
Volumes (mmbtu)	99,900
Average Strike (per mmbtu)	4.00
Fair Value Asset/(Liability)	46,900
Production Period Ending December 31, 2016 [Member] | Natural Gas Fixed Price Swaps [Member]
Derivative [Line Items]
Volumes (mmbtu)	114,500
Average Fixed Price (per mmbtu)	4.460
Fair Value Asset/(Liability)	5,000
Production Period Ending December 31, 2016 [Member] | Natural Gas Put Option [Member]
Derivative [Line Items]
Volumes (mmbtu)	99,900
Average Strike (per mmbtu)	4.15
Fair Value Asset/(Liability)	$ 60,000