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Investments in associates (Details Textual)
shares in Thousands, $ in Thousands
 12 Months Ended
Dec. 31, 2017
USD ($)
$ / Ounce-oz
shares
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2018
$ / Ounce-oz
Disclosure of Investments in associates [Line Items]        
Proportion of ownership interest in associate 45.95% 43.65%    
Impairment loss $ 21,620 $ 0 $ 3,803  
Dividends recognised as distributions to owners $ (28,135) (15,021) (10,488)  
market capitalization of shares   $ 1,311,300    
Number of shares acquired in business combination | shares 63,920      
Percentage of voting equity interests acquired 5.00%      
Consideration transferred, acquisition-date fair value $ 47,900      
Pre-tax discount rate applied to the pre-tax cash flows 8.33%      
Gold [Member]        
Disclosure of Investments in associates [Line Items]        
Commodity price estimates | $ / Ounce-oz 1,221      
Gold [Member] | Scenario, Plan [Member]        
Disclosure of Investments in associates [Line Items]        
Commodity price estimates | $ / Ounce-oz       1,300
Minera Yanacocha S.R.L. [Member]        
Disclosure of Investments in associates [Line Items]        
Proportion of ownership interest in associate 45.95% 43.65%    
Impairment loss $ 0 $ (889,499) 0  
Deferred tax expense arising from write-down or reversal of write-down of deferred tax asset     $ 510,000,000,000  
Dividends recognised as distributions to owners   300,000,000,000    
Recoverable amount of investment in associates, Cash flow projections   $ 528,900    
Sociedad Minera Cerro Verde S.A.A. [Member]        
Disclosure of Investments in associates [Line Items]        
Proportion of ownership interest in associate 19.584% 19.584%    
market capitalization of shares $ 2,036,000      
market capitalization value per share 29.70% 19.11%