v3.5.0.2
Inventories (Details) - USD ($)
$ in Thousands
Jun. 30, 2016
Dec. 31, 2015
Inventory Disclosure [Abstract]    
Finished goods $ 9,317 $ 9,589
Raw materials and precious metals 10,089 9,055
Parts and supplies 33,707 18,885
Total inventories $ 53,113 $ 37,529