Supplementary Information on Oil And Gas Producing Activities (Unaudited) - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015 $ / MMBTU $ / bbl	Dec. 31, 2014 $ / MMBTU $ / bbl
Contingencies [Line Items]
Discount Rate to determine future cash flows	10.00%	10.00%
Gas [Member]
Contingencies [Line Items]
Price for oil and gas | $ / MMBTU	1.43	3.31
Oil [Member]
Contingencies [Line Items]
Price for oil and gas	50.28	94.99
NGL [Member]
Contingencies [Line Items]
Price for oil and gas	12.09	41.74