Annual report pursuant to Section 13 and 15(d)

Income Taxes - Income Tax Years Subject to Examination by Major Tax Jurisdictions (Detail)

v2.4.1.9
Income Taxes - Income Tax Years Subject to Examination by Major Tax Jurisdictions (Detail)
 12 Months Ended
Dec. 31, 2014
United States | Minimum  
Income Tax years subject to examination by major tax jurisdictions  
Income tax examination year under examination 2008
United States | Maximum  
Income Tax years subject to examination by major tax jurisdictions  
Income tax examination year under examination 2014
Gabon | Minimum  
Income Tax years subject to examination by major tax jurisdictions  
Income tax examination year under examination 2007
Gabon | Maximum  
Income Tax years subject to examination by major tax jurisdictions  
Income tax examination year under examination 2014