Income Taxes -Open Tax Years by Major Tax Jurisdiction (Detail)

v2.4.0.6

Income Taxes -Open Tax Years by Major Tax Jurisdiction (Detail)	12 Months Ended
	Dec. 31, 2012
Colombia [Member]
Open Tax Years By Major Jurisdiction [Line Items]
Open Tax Years by Major Tax Jurisdiction	2008-present
Kazakhstan [Member]
Open Tax Years By Major Jurisdiction [Line Items]
Open Tax Years by Major Tax Jurisdiction	2007-present
Mexico [Member]
Open Tax Years By Major Jurisdiction [Line Items]
Open Tax Years by Major Tax Jurisdiction	2007-present
Papua New Guinea [Member]
Open Tax Years By Major Jurisdiction [Line Items]
Open Tax Years by Major Tax Jurisdiction	2010-present
Russia [Member]
Open Tax Years By Major Jurisdiction [Line Items]
Open Tax Years by Major Tax Jurisdiction	2009-present
United States - Federal [Member]
Open Tax Years By Major Jurisdiction [Line Items]
Open Tax Years by Major Tax Jurisdiction	2011-present