Derivative Activities - Derivative Volumes Hedged and Average Hedge Prices (Detail) - Swaps	Dec. 31, 2015 MMBTU / d bbl / d $ / MMBTU $ / bbl $ / gal
Natural Gas | 2016
Derivative [Line Items]
Volume Hedged | MMBTU / d	745,874
Average hedge price | $ / MMBTU	3.24
Natural Gas | 2017
Derivative [Line Items]
Volume Hedged | MMBTU / d	20,000
Average hedge price | $ / MMBTU	3.49
Crude Oil | 2016
Derivative [Line Items]
Volume Hedged	4,247
Average hedge price | $ / bbl	65.27
Crude Oil | 2017
Derivative [Line Items]
Volume Hedged	500
Average hedge price | $ / bbl	55.00
Commodity Contract NGLs (C3 - Propane) | 2016
Derivative [Line Items]
Volume Hedged	5,500
Average hedge price | $ / gal	0.60
Commodity Contract NGLs (NC4 – Normal Butane) | 2016
Derivative [Line Items]
Volume Hedged	2,500
Average hedge price | $ / gal	0.72
Commodity Contract NGLs (C5 - Natural Gasoline) | 2016
Derivative [Line Items]
Volume Hedged	2,749
Average hedge price | $ / gal	1.20