Derivative Financial Instruments - Schedule of Notional Amounts and Estimated Fair Values of Commodity Derivative Positions (Detail) bbl in Thousands, MMBTU in Thousands, $ in Thousands	Mar. 31, 2016 USD ($) MMBTU bbl	Dec. 31, 2015 USD ($) MMBTU bbl
Financial Institution Counterparties [Member] | Oil Commodity Derivative [Member]
Derivative Instruments [Line Items]
Oil/Natural Gas Derivative Assets, Notional Amount | bbl	1,136	1,184
Oil/Natural Gas Derivative Liabilities, Notional Amount | bbl	347	45
Oil/Natural Gas Derivative Assets, Estimated Fair Value	$ 10,742	$ 12,650
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value	$ (536)	$ (352)
Financial Institution Counterparties [Member] | Natural Gas Commodity Derivative [Member]
Derivative Instruments [Line Items]
Oil/Natural Gas Derivative Assets, Notional Amount | MMBTU	3,505	760
Oil/Natural Gas Derivative Liabilities, Notional Amount | MMBTU	730	0
Oil/Natural Gas Derivative Assets, Estimated Fair Value	$ 767	$ 560
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value	$ (84)	$ 0
Customer Counterparties [Member] | Oil Commodity Derivative [Member]
Derivative Instruments [Line Items]
Oil/Natural Gas Derivative Assets, Notional Amount | bbl	347	45
Oil/Natural Gas Derivative Liabilities, Notional Amount | bbl	1,136	1,184
Oil/Natural Gas Derivative Assets, Estimated Fair Value	$ 586	$ 354
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value	$ (10,554)	$ (12,454)
Customer Counterparties [Member] | Natural Gas Commodity Derivative [Member]
Derivative Instruments [Line Items]
Oil/Natural Gas Derivative Assets, Notional Amount | MMBTU	730	0
Oil/Natural Gas Derivative Liabilities, Notional Amount | MMBTU	3,505	760
Oil/Natural Gas Derivative Assets, Estimated Fair Value	$ 107	$ 0
Oil/Natural Gas Derivative Liabilities, Estimated Fair Value	$ (689)	$ (549)