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Inventory, net (Details 3) - Minera Yanacocha SRL and subsidiary [Member] - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Disclosure of inventory net [Line Items]      
Provision for impairment of materials and supplies $ 2,896 $ 3,104 $ 5,060
Reversal of provision for impairment of materials and supplies (1,092) (3,713) (4,011)
Opening balance 5,272 5,881 4,832
Ending balance $ 7,076 $ 5,272 $ 5,881