Derivative Activities - Derivative Volumes Hedged and Average Hedge Prices (Detail)	Jun. 30, 2014 MMBTU
Natural Gas 2014 | Collars
Derivative [Line Items]
Volume Hedged	447,500
Average floor price	3.84
Average cap price	4.48
Natural Gas 2014 | Swaps
Derivative [Line Items]
Volume Hedged	260,000
Average hedge price	4.18
Natural Gas 2015 | Collars
Derivative [Line Items]
Volume Hedged	145,000
Average floor price	4.07
Average cap price	4.56
Natural Gas 2015 | Swaps
Derivative [Line Items]
Volume Hedged	287,432
Average hedge price	4.22
Natural Gas 2016 | Swaps
Derivative [Line Items]
Volume Hedged	90,000
Average hedge price	4.21
Crude Oil 2014 | Collars
Derivative [Line Items]
Volume Hedged	2,000
Average floor price	85.55
Average cap price	100.00
Crude Oil 2014 | Swaps
Derivative [Line Items]
Volume Hedged	9,500
Average hedge price	94.35
Crude Oil 2015 | Swaps
Derivative [Line Items]
Volume Hedged	9,626
Average hedge price	90.57
Crude Oil 2016 | Swaps
Derivative [Line Items]
Volume Hedged	501
Average hedge price	91.10
NGLs (C3 - Propane) 2014 | Swaps
Derivative [Line Items]
Volume Hedged	12,000
Average hedge price	1.02
NGLs (C3 - Propane) 2015 | Swaps
Derivative [Line Items]
Volume Hedged	1,000
Average hedge price	1.10
NGLs (NC4 - Normal Butane) 2014 | Swaps
Derivative [Line Items]
Volume Hedged	4,000
Average hedge price	1.34
NGLs (C5 - Natural Gasoline) 2014 | Swaps
Derivative [Line Items]
Volume Hedged	3,500
Average hedge price	2.17
NGLs (C5 - Natural Gasoline) 2015 | Swaps
Derivative [Line Items]
Volume Hedged	500
Average hedge price	2.14