Risk Management and Derivative Instruments - Open Commodity Positions (Detail)	6 Months Ended
	Jun. 30, 2019 MMBTU $ / MMBTU $ / bbl bbl
Natural Gas Derivative Contracts Fixed Price Swap 2022 [Member]
Derivative [Line Items]
Average monthly volume (MMBtu) | MMBTU	0
Weighted-average fixed price | $ / MMBTU	0
Natural Gas Derivative Collar Contracts 2022 [Member]
Derivative [Line Items]
Average monthly volume (MMBtu) | MMBTU	0
Weighted-average floor price	0
Weighted-average ceiling price	0
Crude Oil Derivative Contracts Fixed Price Swap 2022 [Member]
Derivative [Line Items]
Average monthly volume (Bbls) | bbl	30,000
Weighted-average fixed price	55.32
Crude Oil Derivative Collar Contracts 2022 [Member]
Derivative [Line Items]
Average monthly volume (MMBtu) | MMBTU	0
Weighted-average floor price	0
Weighted-average ceiling price	0
NGL Derivative Contracts Fixed Price Swap 2022 [Member]
Derivative [Line Items]
Average monthly volume (Bbls) | bbl	0
Weighted-average fixed price	0
Natural Gas Derivative Contracts Fixed Price Swap 2021 [Member]
Derivative [Line Items]
Average monthly volume (MMBtu) | MMBTU	187,500
Weighted-average fixed price | $ / MMBTU	2.56
Natural Gas Derivative Collar Contracts 2021 [Member]
Derivative [Line Items]
Average monthly volume (MMBtu) | MMBTU	162,500
Weighted-average floor price	2.58
Weighted-average ceiling price	2.84
Crude Oil Derivative Contracts Fixed Price Swap 2021 [Member]
Derivative [Line Items]
Average monthly volume (Bbls) | bbl	116,250
Weighted-average fixed price	56.05
Crude Oil Derivative Collar Contracts 2021 [Member]
Derivative [Line Items]
Average monthly volume (MMBtu) | MMBTU	0
Weighted-average floor price	0
Weighted-average ceiling price	0
NGL Derivative Contracts Fixed Price Swap 2021 [Member]
Derivative [Line Items]
Average monthly volume (Bbls) | bbl	22,800
Weighted-average fixed price	27.48
Natural Gas Derivative Contracts Fixed Price Swap 2020 [Member]
Derivative [Line Items]
Average monthly volume (MMBtu) | MMBTU	150,000
Weighted-average fixed price | $ / MMBTU	2.65
Natural Gas Derivative Collar Contracts 2020 [Member]
Derivative [Line Items]
Average monthly volume (MMBtu) | MMBTU	520,000
Weighted-average floor price	2.64
Weighted-average ceiling price	2.96
Crude Oil Derivative Contracts Fixed Price Swap 2020 [Member]
Derivative [Line Items]
Average monthly volume (Bbls) | bbl	153,050
Weighted-average fixed price	57.54
Crude Oil Derivative Collar Contracts 2020 [Member]
Derivative [Line Items]
Average monthly volume (MMBtu) | MMBTU	14,300
Weighted-average floor price	55.00
Weighted-average ceiling price	62.10
NGL Derivative Contracts Fixed Price Swap 2020 [Member]
Derivative [Line Items]
Average monthly volume (Bbls) | bbl	65,425
Weighted-average fixed price	28.84
Natural Gas Derivative Contracts Fixed Price Swap Remaining 2019 [Member]
Derivative [Line Items]
Average monthly volume (MMBtu) | MMBTU	1,490,000
Weighted-average fixed price | $ / MMBTU	2.85
Natural Gas Derivative Collar Contracts Remaining 2019 [Member]
Derivative [Line Items]
Average monthly volume (MMBtu) | MMBTU	0
Weighted-average floor price	0
Weighted-average ceiling price	0
Crude Oil Derivative Contracts Fixed Price Swap Remaining 2019 [Member]
Derivative [Line Items]
Average monthly volume (Bbls) | bbl	135,000
Weighted-average fixed price	53.49
Crude Oil Derivative Collar Contracts Remaining 2019 [Member]
Derivative [Line Items]
Average monthly volume (MMBtu) | MMBTU	76,000
Weighted-average floor price	55.00
Weighted-average ceiling price	63.85
NGL Derivative Contracts Fixed Price Swap Remaining 2019 [Member]
Derivative [Line Items]
Average monthly volume (Bbls) | bbl	72,000
Weighted-average fixed price	29.96