Derivative Activities - Derivative Volumes Hedged and Average Hedge Prices (Detail) - Swaps	Jun. 30, 2016 MMBTU / d bbl / d $ / MMBTU $ / bbl $ / gal
Natural Gas | 2016
Derivative [Line Items]
Volume Hedged | MMBTU / d	788,315
Weighted Average Hedge Price | $ / MMBTU	3.22
Natural Gas | 2017
Derivative [Line Items]
Volume Hedged | MMBTU / d	300,000
Weighted Average Hedge Price | $ / MMBTU	2.91
Natural Gas | 2018
Derivative [Line Items]
Volume Hedged | MMBTU / d	70,000
Weighted Average Hedge Price | $ / MMBTU	2.92
Crude Oil | 2016
Derivative [Line Items]
Volume Hedged	6,000
Weighted Average Hedge Price | $ / bbl	58.40
Crude Oil | 2017
Derivative [Line Items]
Volume Hedged	2,496
Weighted Average Hedge Price | $ / bbl	51.29
Commodity Contract NGLs (C2 - Ethane) | 2016
Derivative [Line Items]
Volume Hedged	500
Weighted Average Hedge Price | $ / gal	0.22
Commodity Contract NGLs (C2 - Ethane) | 2017
Derivative [Line Items]
Volume Hedged	3,000
Weighted Average Hedge Price | $ / gal	0.27
Commodity Contract NGLs (C3 - Propane) | 2016
Derivative [Line Items]
Volume Hedged	5,500
Weighted Average Hedge Price | $ / gal	0.60
Commodity Contract NGLs (C3 - Propane) | 2017
Derivative [Line Items]
Volume Hedged	3,966
Weighted Average Hedge Price | $ / gal	0.53
Commodity Contract NGLs (NC4 - Normal Butane) | 2016
Derivative [Line Items]
Volume Hedged	4,750
Weighted Average Hedge Price | $ / gal	0.66
Commodity Contract NGLs (NC4 - Normal Butane) | 2017
Derivative [Line Items]
Volume Hedged	500
Weighted Average Hedge Price | $ / gal	0.61
Commodity Contract NGLs (C5 - Natural Gasoline) | 2016
Derivative [Line Items]
Volume Hedged	3,500
Weighted Average Hedge Price | $ / gal	1.11
Commodity Contract NGLs (C5 - Natural Gasoline) | 2017
Derivative [Line Items]
Volume Hedged	1,750
Weighted Average Hedge Price | $ / gal	0.97