Supplemental Oil and Gas Information (Unaudited) - Schedule of Product Prices Used for Valuing the Reserves (Detail)	12 Months Ended
	Dec. 31, 2016 $ / MMBTU $ / bbl	Dec. 31, 2015 $ / MMBTU $ / bbl	Dec. 31, 2014 $ / MMBTU $ / bbl
Oil [Member]
Supplemental Oil And Gas Reserve Information [Line Items]
Product prices for reserves	42.75	46.79	91.48
NGL [Member]
Supplemental Oil And Gas Reserve Information [Line Items]
Product prices for reserves	42.75	46.79	91.48
Natural Gas [Member]
Supplemental Oil And Gas Reserve Information [Line Items]
Product prices for reserves | $ / MMBTU	2.48	2.58	4.35