v3.26.1
Segmented information (Schedule of segments, assets and liabilities) (Details) - USD ($)
$ in Millions
Dec. 31, 2025
Dec. 31, 2024
Disclosure of operating segments [line items]    
Total assets $ 6,223.3 $ 5,487.6
Total liabilities 2,992.3 2,840.2
Property, plant and equipment 4,693.9 4,181.4
Other Non-Current Assets 96.3 73.8
Peru [Member]    
Disclosure of operating segments [line items]    
Total assets 2,492.0 2,410.0
Total liabilities 1,031.3 960.0
Property, plant and equipment 1,815.7 1,897.1
Other Non-Current Assets 64.3 47.8
Manitoba [Member]    
Disclosure of operating segments [line items]    
Total assets 471.5 547.4
Total liabilities 424.3 421.3
Property, plant and equipment 604.3 595.1
Other Non-Current Assets 21.4 17.2
British Columbia [Member]    
Disclosure of operating segments [line items]    
Total assets 1,320.2 1,076.0
Total liabilities 269.2 281.9
Property, plant and equipment 1,082.6 900.7
Other Non-Current Assets 9.9 8.0
Arizona [Member]    
Disclosure of operating segments [line items]    
Total assets 1,147.5 757.3
Total liabilities 103.6 14.7
Property, plant and equipment 1,144.9 747.1
Other Non-Current Assets 0.2 0.2
Corporate and other activities [Member]    
Disclosure of operating segments [line items]    
Total assets 792.1 696.9
Total liabilities 1,163.9 1,162.3
Property, plant and equipment 46.4 41.4
Other Non-Current Assets 0.5 0.6
Corporate and other activities [Member] | Nevada [Member]    
Disclosure of operating segments [line items]    
Property, plant and equipment $ 33.9 $ 27.7