v3.26.1
Mineral Property, Plant and Equipment (Narrative) (Details)
$ in Millions
 9 Months Ended 12 Months Ended
Apr. 03, 2024
USD ($)
shares
Sep. 30, 2024
USD ($)
Dec. 31, 2025
USD ($)
$ / oz
Dec. 31, 2025
USD ($)
$ / shares
Dec. 31, 2024
USD ($)
Dec. 31, 2024
USD ($)
$ / shares
Disclosure of detailed information about property, plant and equipment [line items]            
Reversal of impairment expense   $ 57.1        
Share price (cad per share) | $ / shares       $ 53.00   $ 26.52
Depreciation, right-of-use assets     $ 12.5      
Interest capitalized to mineral property, plant and equipment     $ 17.1   $ 7.7  
Capitalisation rate of borrowing costs eligible for capitalisation     6.32%   7.03%  
Construction in progress     $ 657.8 $ 657.8 $ 414.0 $ 414.0
Year One Through Year Three [Member] | Maximum            
Disclosure of detailed information about property, plant and equipment [line items]            
Average realized price per ounce | $ / oz     2,300      
Year One Through Year Three [Member] | Minimum            
Disclosure of detailed information about property, plant and equipment [line items]            
Average realized price per ounce | $ / oz     2,120      
Phase 3+ Expansion Project            
Disclosure of detailed information about property, plant and equipment [line items]            
Interest capitalized to mineral property, plant and equipment     $ 24.9   $ 11.3  
Capitalisation rate of borrowing costs eligible for capitalisation     6.32%      
Right of Use Assets            
Disclosure of detailed information about property, plant and equipment [line items]            
Right-of-use assets     $ (29.0) $ (29.0)    
Orford Mining Corporation            
Disclosure of detailed information about property, plant and equipment [line items]            
Number of shares issued (in shares) | shares 0.005588          
Number of shares in entity held by entity (in shares) | shares 61,660,902          
Percentage of shares held by entity 27.50%          
Consideration transferred, acquisition-date fair value $ 20.7          
Acquisition-related costs $ 1.0