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Basis for preparation, consolidation and accounting policies - Additional information (Details)
 12 Months Ended
Jan. 01, 2019
USD ($)
Jan. 01, 2017
Dec. 31, 2019
USD ($)
item
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Basis for preparation, consolidation and accounting policies          
Useful lives or depreciation of Investment property     20 years    
Impairment loss     $ 2,083,000 $ 5,693,000 $ 21,620,000
Workers' profit sharing rate     8.00%    
Qualifying asset, description     The Group defines a qualifying asset as one which value is greater than US$5 million and requires a longer period to 12 months to get ready for its intended use.    
Applicable tax rate     29.50% 32.00% 32.00%
Lease Liabilities $ 261,538,000   $ 7,503,000    
Right-of-use assets     $ 6,185,000    
Lease term     10 years    
Maximum [Member]          
Basis for preparation, consolidation and accounting policies          
Useful life of intangible assets     10 years    
Mining Royalties Marginal Rate     12.00%    
Normal credit term     90 days    
Minimum [Member]          
Basis for preparation, consolidation and accounting policies          
Useful life of intangible assets     1 year    
Mining Royalties Marginal Rate     1.00%    
Normal credit term     30 days    
Written put options [member]          
Basis for preparation, consolidation and accounting policies          
Closing foreign exchange rate     0.3015 0.2959  
Purchased call options [member]          
Basis for preparation, consolidation and accounting policies          
Closing foreign exchange rate     0.3020 0.2968  
Minera Yanacocha SRL and subsidiary [Member]          
Basis for preparation, consolidation and accounting policies          
Applicable tax rate 29.00% 29.50% 29.50% 29.50% 29.50%
Interest from short-term money market funds and interest from current bank accounts     $ 18,430,000 $ 11,448,000 $ 5,831,000
Terminal compensation percentage     1.50%    
Maximum severance payments | item     12    
Sociedad Minera Cerro Verde S.A.A. [Member]          
Basis for preparation, consolidation and accounting policies          
Impairment loss       $ 0  
Applicable tax rate     32.00% 32.00% 32.00%
Lease Liabilities $ 95,728,000        
Right-of-use assets     $ 84,856,000 $ 95,728,000  
Weighted average incremental borrowing rate at transition 4.704%        
Sociedad Minera Cerro Verde S.A.A. [Member] | Written put options [member]          
Basis for preparation, consolidation and accounting policies          
Closing foreign exchange rate     3.317 3.379  
Sociedad Minera Cerro Verde S.A.A. [Member] | Purchased call options [member]          
Basis for preparation, consolidation and accounting policies          
Closing foreign exchange rate     3.311 3.369  
Plant and equipment [Member] | Minera Yanacocha SRL and subsidiary [Member] | Maximum [Member]          
Basis for preparation, consolidation and accounting policies          
Lease term     10 years    
Plant and equipment [Member] | Minera Yanacocha SRL and subsidiary [Member] | Minimum [Member]          
Basis for preparation, consolidation and accounting policies          
Lease term     3 years    
Buildings          
Basis for preparation, consolidation and accounting policies          
Lease Liabilities     $ 5,296,000    
Right-of-use assets     $ 4,602,000    
Buildings | Minera Yanacocha SRL and subsidiary [Member] | Maximum [Member]          
Basis for preparation, consolidation and accounting policies          
Lease term     10 years    
Buildings | Minera Yanacocha SRL and subsidiary [Member] | Minimum [Member]          
Basis for preparation, consolidation and accounting policies          
Lease term     5 years    
OSINERGMIN [Member]          
Basis for preparation, consolidation and accounting policies          
Contribution rate on sales invoice value     0.13% 0.14% 0.15%
OEFA [Member]          
Basis for preparation, consolidation and accounting policies          
Contribution rate on sales invoice value     0.11% 0.11% 0.11%