Derivative Instruments and Hedging Activities (Details 2) (USD $)	Feb. 21, 2012 MMBtusd
2011 Hedging Position One [Member] | Natural Gas [Member]
Hedging Positions
Daily Volume	10,000
Swap Price	$ 5.035
2011 Hedging Position One [Member] | Oil [Member]
Hedging Positions
Daily Volume	1,000
Swap Price	90.3
2011 Hedging Position Two [Member] | Natural Gas [Member]
Hedging Positions
Daily Volume	10,000
Swap Price	5.040
2011 Hedging Position Two [Member] | Oil [Member]
Hedging Positions
Daily Volume	1,000
Swap Price	90.41
2011 Hedging Position Three [Member] | Natural Gas [Member]
Hedging Positions
Daily Volume	10,000
Swap Price	5.050
2011 Hedging Position Three [Member] | Oil [Member]
Hedging Positions
Daily Volume	1,000
Swap Price	90.45
2011 Hedging Position Four [Member] | Oil [Member]
Hedging Positions
Daily Volume	1,000
Swap Price	95.50
2011 Hedging Position Five [Member] | Oil [Member]
Hedging Positions
Daily Volume	2,000
Swap Price	97.60
2011 Hedging Position Six [Member] | Oil [Member]
Hedging Positions
Daily Volume	1,000
Swap Price	98.15
2011 Hedging Position Seven [Member] | Oil [Member]
Hedging Positions
Daily Volume	1,000
Swap Price	100.00
2011 Hedging Position Eight [Member] | Oil [Member]
Hedging Positions
Daily Volume	1,000
Swap Price	101.55
2011 Hedging Position Nine [Member] | Oil [Member]
Hedging Positions
Daily Volume	1,000
Swap Price	104.25
2011 Hedging Position Ten [Member] | Oil [Member]
Hedging Positions
Daily Volume	1,000
Swap Price	111.02
2012 Hedging Position One [Member] | Natural Gas [Member]
Hedging Positions
Daily Volume	10,000
Swap Price	5.270
2012 Hedging Position Two [Member] | Natural Gas [Member]
Hedging Positions
Daily Volume	10,000
Swap Price	5.320
2012 Hedging Position Two [Member] | Oil [Member]
Hedging Positions
Daily Volume	1,000
Swap Price	94.45
2012 Hedging Position Three [Member] | Oil [Member]
Hedging Positions
Daily Volume	1,000
Swap Price	94.60
2012 Hedging Position Four [Member] | Oil [Member]
Hedging Positions
Daily Volume	1,000
Swap Price	97.15
2012 Hedging Position Five [Member] | Oil [Member]
Hedging Positions
Daily Volume	1,000
Swap Price	101.53
2012 Hedging Position Six [Member] | Oil [Member]
Hedging Positions
Daily Volume	1,000
Swap Price	103.00
2012 Hedging Position Seven [Member] | Oil [Member]
Hedging Positions
Daily Volume	1,000
Swap Price	104.50
2012 Hedging Position Eight [Member] | Oil [Member]
Hedging Positions
Daily Volume	1,000
Swap Price	107.30
2013 Hedging Position One [Member] | Oil [Member]
Hedging Positions
Daily Volume	1,000
Swap Price	$ 103.30