Income Taxes - Tax Years Subject to Examination by Tax Authorities (Detail)	12 Months Ended
	Dec. 31, 2012
Brazil [Member]
Schedule Of Income Taxes [Line Items]
Income tax examination, year(s) under examination	2006 - 2012
Canada [Member]
Schedule Of Income Taxes [Line Items]
Income tax examination, year(s) under examination	2005 - 2012
Mexico [Member]
Schedule Of Income Taxes [Line Items]
Income tax examination, year(s) under examination	2007 - 2012
Norway [Member]
Schedule Of Income Taxes [Line Items]
Income tax examination, year(s) under examination	2003 - 2012
Russia [Member]
Schedule Of Income Taxes [Line Items]
Income tax examination, year(s) under examination	2009 - 2012
Saudi Arabia [Member]
Schedule Of Income Taxes [Line Items]
Income tax examination, year(s) under examination	2001 - 2012
United Kingdom [Member]
Schedule Of Income Taxes [Line Items]
Income tax examination, year(s) under examination	2009 - 2012
United States [Member]
Schedule Of Income Taxes [Line Items]
Income tax examination, year(s) under examination	2008 - 2012