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Inventories (Tables)
 6 Months Ended
Jun. 30, 2017
Inventories  
Schedule of Inventories

Inventories are stated at lower of cost or net realizable value. Cost is determined using a weighted average cost method for raw materials and supplies, and on a first-in, first-out, basis for other inventory. Inventory consisted of the following (in thousands):











 

 

 

 

 

 

 

 

 



 

 

 

 

 

 

 

 

 



 

 

June 30,

 

December 31,

 

 



 

 

2017

 

2016

 

 



 

Raw materials

$

 616,240 

 

$

 515,924 

 

 



 

Supplies

 

 375,453 

 

 

 383,134 

 

 



 

Work in progress

 

 124,949 

 

 

 103,606 

 

 



 

Finished goods

 

 302,090 

 

 

 272,547 

 

 



 

Total inventories

$

 1,418,732 

 

$

 1,275,211