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Inventories (Details) - USD ($)
$ in Thousands
Sep. 30, 2017
Dec. 31, 2016
Inventories    
Raw materials $ 677,187 $ 515,924
Supplies 376,984 383,134
Work in progress 119,735 103,606
Finished goods 313,610 272,547
Total inventories $ 1,487,516 $ 1,275,211