XML 69 R48.htm IDEA: XBRL DOCUMENT v3.3.1.900
Related party transactions (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Related Party Transaction [Line Items]      
Net sales to Glencore $ 1,867,711 $ 1,262,101 $ 511,051
Glencore [Member]      
Related Party Transaction [Line Items]      
Net sales to Glencore 1,867,711 1,262,101 511,051
Purchases from Glencore 393,158 285,167 173,693
BHH [Member]      
Related Party Transaction [Line Items]      
Purchases from BHH $ 46,592 $ 47,804 $ 86,678