Derivative Activities (Details) (USD $)	Jun. 30, 2011
Derivative volumes hedged and average hedge prices
Average price of oil call option (per barrel)	$ 83.15
Collars [Member] | Crude Oil 2012 [Member]
Derivative volumes hedged and average hedge prices
Volume Hedged	2,000 bbls/day
Average floor price	70.00
Average cap price	80.00
Collars [Member] | Natural Gas 2011 [Member]
Derivative volumes hedged and average hedge prices
Volume Hedged	333200 Mmbtu/day
Average floor price	5.38
Average cap price	6.23
Collars [Member] | Natural Gas 2012 [Member]
Derivative volumes hedged and average hedge prices
Volume Hedged	189641 Mmbtu/day
Average floor price	5.32
Average cap price	5.91
Collars [Member] | Natural Gas 2013 [Member]
Derivative volumes hedged and average hedge prices
Volume Hedged	160,000 Mmbtu/day
Average floor price	5.09
Average cap price	5.65
Swap [Member] | Natural Gas 2012 [Member]
Derivative volumes hedged and average hedge prices
Volume Hedged	70,192 Mmbtu/day
Average hedge price	5.00
Swap [Member] | NGL 2011 [Member]
Derivative volumes hedged and average hedge prices
Volume Hedged	7,000 bbls/day
Average hedge price	104.17
Swap [Member] | NGL 2012 [Member]
Derivative volumes hedged and average hedge prices
Volume Hedged	5,000 bbls/day
Average hedge price	102.59
Call Option [Member] | Crude Oil 2011 [Member]
Derivative volumes hedged and average hedge prices
Volume Hedged	5,500 bbls/day
Average price of oil call option (per barrel)	80.00
Call Option [Member] | Crude Oil 2012 [Member]
Derivative volumes hedged and average hedge prices
Volume Hedged	4,700 bbls/day
Average price of oil call option (per barrel)	85.00
Natural Gas [Member]
Derivative volumes hedged and average hedge prices
Average floor price	5.27
Average cap price	5.93
Average hedge price	5.00
NGL [Member]
Derivative volumes hedged and average hedge prices
Average hedge price	$ 103.24