XML 108 R93.htm IDEA: XBRL DOCUMENT v3.8.0.1
INVESTMENTS IN NON-CONSOLIDATED COMPANIES INVESTMENTS IN NON-CONSOLIDATED COMPANIES (Schedule of principal in non-consolidated companies) (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Disclosure of unconsolidated structured entities [line items]      
Investments in non-consolidated companies $ 478,348 $ 418,379 $ 250,412
USINAS SIDEÚRGICAS DE MINAS GERAIS S.A.      
Disclosure of unconsolidated structured entities [line items]      
Proportion of voting rights held by non-consolidated companies 20.47%    
Investments in non-consolidated companies $ 466,299 411,134 $ 239,960
Other non-consolidated companies      
Disclosure of unconsolidated structured entities [line items]      
Investments in non-consolidated companies $ 5,187 $ 3,801  
Brazil | USINAS SIDEÚRGICAS DE MINAS GERAIS S.A.      
Disclosure of unconsolidated structured entities [line items]      
Proportion of voting rights held by non-consolidated companies 34.39% 34.39%  
Investments in non-consolidated companies $ 466,299 $ 411,134  
Mexico | Techgen S.A. de C.V.      
Disclosure of unconsolidated structured entities [line items]      
Proportion of voting rights held by non-consolidated companies 48.00% 48.00%  
Investments in non-consolidated companies $ 6,862 $ 3,444