v3.26.1
Acquisition of Argonaut Gold, Inc. (Schedule of Asset Acquisition) (Details)
shares in Millions, $ in Millions
 12 Months Ended
Jul. 12, 2024
USD ($)
$ / shares
$ / oz
oz
shares
Jul. 12, 2024
USD ($)
$ / shares
oz
$ / shares
Apr. 04, 2024
USD ($)
Dec. 31, 2025
USD ($)
Dec. 31, 2025
USD ($)
$ / shares
Dec. 31, 2024
USD ($)
Dec. 31, 2024
USD ($)
$ / shares
Jul. 15, 2024
oz
Dec. 31, 2023
USD ($)
Net assets acquired                  
Deferred tax asset       $ 0.0 $ 0.0 $ 61.2 $ 61.2    
Share price (cad per share) | $ / shares         $ 53.00   $ 26.52    
Borrowings       200.0 $ 200.0 250.0 $ 250.0   $ 0.0
Repayments of borrowings $ 308.3     50.0   308.3      
Cost                  
Net assets acquired                  
Acquisition of Argonaut (Note 6)           21.1      
Mineral Property | Cost                  
Net assets acquired                  
Acquisition of Argonaut (Note 6)           0.0      
Forward contract                  
Net assets acquired                  
Ounces subject to contract | oz 329,417 329,417              
Ounces subject to contract, settled | oz               179,417  
Forward contract | Bottom of range                  
Net assets acquired                  
Average realized price per ounce | $ / oz 1,821                
Forward contract | Top of range                  
Net assets acquired                  
Average realized price per ounce | $ / oz 1,860                
Revolving Credit Facility                  
Net assets acquired                  
Borrowings $ 218.0 $ 218.0   200.0 200.0        
Revolving Credit Facility | Cost                  
Net assets acquired                  
Borrowings       $ 200.0 $ 200.0        
Convertible Debentures                  
Net assets acquired                  
Borrowings 57.5 57.5              
Obligation Prepayment                  
Net assets acquired                  
Borrowings $ 24.2 $ 24.2              
Florida Canyon Gold                  
Net assets acquired                  
Percentage of voting equity interests acquired 19.90% 19.90%              
Argonaut Transaction                  
Consideration transferred                  
Fair value of total shares issued as of acquisition date $ 360.1 $ 360.1              
Fair value of interest prior to acquisition date 58.9 58.9              
Total consideration transferred, acquisition-date fair value 419.0 419.0              
Net assets acquired                  
Cash and cash equivalents 6.7 6.7              
Receivables and other assets 6.2 6.2              
Inventories 38.6 38.6              
Deferred tax asset 61.2 61.2              
Accrued liabilities and other liabilities 88.7 88.7              
Debt (299.7) (299.7)       (299.7) (299.7)    
Other long term liabilities (4.6) (4.6)              
Derivative hedge liabilities (226.0) (226.0)              
Lease liabilities (47.2) (47.2)       (47.2) $ (47.2)    
Decommissioning liability (18.0) (18.0)              
Identifiable assets acquired (liabilities assumed) $ 419.0 $ 419.0              
Share price (cad per share) | $ / shares   $ 0.51              
Closing foreign exchange rate | $ / shares 1.3616 1.3616              
Right-of-use assets $ 47.2 $ 47.2              
Repayments of borrowings           308.3      
Acquisition of Argonaut (Note 6)           683.2      
Argonaut Transaction | Cost                  
Net assets acquired                  
Acquisition of Argonaut (Note 6) 683.2         990.5      
Argonaut Transaction | Mineral Property                  
Net assets acquired                  
Acquisition of Argonaut (Note 6)           307.3      
Argonaut Transaction | Mineral Property | Cost                  
Net assets acquired                  
Acquisition of Argonaut (Note 6) $ 307.3                
Argonaut Transaction | Revolving Credit Facility                  
Net assets acquired                  
Repayments of borrowings           $ 299.7      
Argonaut Transaction | Argonaut                  
Consideration transferred                  
Total consideration transferred, acquisition-date fair value     $ 58.9            
Net assets acquired                  
Proportion of ownership interests held by non-controlling interests 13.80%   13.80%            
Argonaut Transaction | Florida Canyon Gold                  
Net assets acquired                  
Percentage of voting equity interests acquired 19.99% 19.99%              
Argonaut Transaction | Ordinary shares                  
Net assets acquired                  
Share price (cad per share) | $ / shares   $ 24.02              
Closing foreign exchange rate | $ / shares 1.3616 1.3616              
Number of shares issued (in shares) | shares 20.4