Derivative Activities - Derivative Volumes Hedged and Average Hedge Prices (Detail)	Jun. 30, 2017 MMBTU / d bbl / d $ / MMBTU $ / bbl $ / gal
2017 Commodity Contract | Swaps | Natural Gas
Derivative [Line Items]
Volume Hedged | MMBTU / d	865,000	[1]
Weighted Average Hedge Price | $ / MMBTU	3.21	[1]
2017 Commodity Contract | Swaps | Crude Oil
Derivative [Line Items]
Volume Hedged	8,761	[1]
Weighted Average Hedge Price | $ / bbl	56.38	[1]
2017 Commodity Contract | Swaps | NGLs (C2-Ethane)
Derivative [Line Items]
Volume Hedged	3,000
Weighted Average Hedge Price | $ / gal	0.27
2017 Commodity Contract | Swaps | NGLs (C3-Propane)
Derivative [Line Items]
Volume Hedged	13,826
Weighted Average Hedge Price | $ / gal	0.57
2017 Commodity Contract | Swaps | NGLs (NC4-Normal Butane)
Derivative [Line Items]
Volume Hedged	7,875
Weighted Average Hedge Price | $ / gal	0.75
2017 Commodity Contract | Swaps | NGLs (C5-Natural Gasoline)
Derivative [Line Items]
Volume Hedged	5,500
Weighted Average Hedge Price | $ / gal	1.07
2017 Commodity Contract | Collars | Natural Gas
Derivative [Line Items]
Volume Hedged | MMBTU / d	122,609	[1]
Weighted Average Floor Price | $ / MMBTU	3.45	[1]
Weighted Average Cap Price | $ / MMBTU	4.11	[1]
2017 Commodity Contract | Puts | Purchased | Natural Gas
Derivative [Line Items]
Volume Hedged | MMBTU / d	185,870	[1]
Weighted Average Hedge Price | $ / MMBTU	3.50	[1],[2]
2017 Commodity Contract | Calls | Sold | Natural Gas
Derivative [Line Items]
Volume Hedged | MMBTU / d	23,370
Weighted Average Hedge Price | $ / MMBTU	3.70	[3]
2018 Commodity Contract | Swaps | Natural Gas
Derivative [Line Items]
Volume Hedged | MMBTU / d	417,260
Weighted Average Hedge Price | $ / MMBTU	3.25
2018 Commodity Contract | Swaps | Crude Oil
Derivative [Line Items]
Volume Hedged	5,250
Weighted Average Hedge Price | $ / bbl	53.20
2018 Commodity Contract | Swaps | NGLs (C2-Ethane)
Derivative [Line Items]
Volume Hedged	250
Weighted Average Hedge Price | $ / gal	0.29
2018 Commodity Contract | Swaps | NGLs (C3-Propane)
Derivative [Line Items]
Volume Hedged	7,199
Weighted Average Hedge Price | $ / gal	0.65
2018 Commodity Contract | Swaps | NGLs (NC4-Normal Butane)
Derivative [Line Items]
Volume Hedged	4,250
Weighted Average Hedge Price | $ / gal	0.81
2018 Commodity Contract | Swaps | NGLs (C5-Natural Gasoline)
Derivative [Line Items]
Volume Hedged	1,500
Weighted Average Hedge Price | $ / gal	1.19
2018 Commodity Contract | Collars | Natural Gas
Derivative [Line Items]
Volume Hedged | MMBTU / d	60,000
Weighted Average Floor Price | $ / MMBTU	3.40
Weighted Average Cap Price | $ / MMBTU	3.76
2019 Commodity Contract | Swaps | Crude Oil
Derivative [Line Items]
Volume Hedged	500
Weighted Average Hedge Price | $ / bbl	51.75

[1] Includes derivative instruments assumed in connection with the MRD Merger.

[2] Weighted average deferred premium is ($0.32).

[3] Weighted average deferred premium is $0.27.