Property, Plant and Equipment - Additional Information (Detail) (USD $)	Mar. 31, 2014 Site	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Total capitalized exploratory well costs	$ 395,949,000	$ 393,030,000	$ 444,228,000	$ 445,697,000
Exploratory well costs capitalized more than one year	363,800,000
Number of drilling areas where appraisal/development is planned or under stages of completion	3
Malaysia [Member]
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs capitalized more than one year	213,800,000
United States [Member]
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs capitalized more than one year	116,200,000
Brunei
Projects with Exploratory Well Costs Capitalized for More than One Year [Line Items]
Exploratory well costs capitalized more than one year	$ 33,800,000