Schedule of Prices Weighted by Field Production Related to Proved Reserves (Detail)

v2.4.0.8

Schedule of Prices Weighted by Field Production Related to Proved Reserves (Detail)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Oil
Reserve Quantities [Line Items]
Weighted price	99.65	98.13	97.36	76.28
NGLs
Reserve Quantities [Line Items]
Weighted price	35.21	47.30	51.30	44.92
Natural Gas
Reserve Quantities [Line Items]
Weighted price	3.80	2.77	4.11	4.57