v3.26.1
Financial Instruments and Risk Management (Foreign Currency Exchange Rate Risk) (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Total financial instrument exposure to credit risk $ (929.6) $ (331.4)
Currency risk | Canadian dollar    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Impact on pre-tax earnings 14.8 14.5
Total financial instrument exposure to credit risk (113.0) (144.8)
Currency risk | Mexican peso    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Impact on pre-tax earnings 6.2 5.3
Total financial instrument exposure to credit risk (55.6) (48.0)
Cash and cash equivalents | Currency risk | Canadian dollar    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Total financial instrument exposure to credit risk (24.7) (18.9)
Cash and cash equivalents | Currency risk | Mexican peso    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Total financial instrument exposure to credit risk (2.0) (11.8)
Equity securities | Currency risk | Canadian dollar    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Total financial instrument exposure to credit risk (58.9) (24.0)
Equity securities | Currency risk | Mexican peso    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Total financial instrument exposure to credit risk 0.0 0.0
Trade receivables | Currency risk | Canadian dollar    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Total financial instrument exposure to credit risk (31.4) (35.9)
Trade receivables | Currency risk | Mexican peso    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Total financial instrument exposure to credit risk (13.4) (10.1)
Accounts Payable And Accrued Liabilities | Currency risk | Canadian dollar    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Total financial instrument exposure to credit risk (204.9) (153.6)
Accounts Payable And Accrued Liabilities | Currency risk | Mexican peso    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Total financial instrument exposure to credit risk (24.2) (17.7)
Income Taxes Payable | Currency risk | Canadian dollar    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Total financial instrument exposure to credit risk (19.2) (3.2)
Income Taxes Payable | Currency risk | Mexican peso    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Total financial instrument exposure to credit risk (34.4) (45.6)
Other Monetary (Liabilities) Assets | Currency risk | Canadian dollar    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Total financial instrument exposure to credit risk (3.9) (66.8)
Other Monetary (Liabilities) Assets | Currency risk | Mexican peso    
Disclosure of nature and extent of risks arising from financial instruments [line items]    
Total financial instrument exposure to credit risk $ (12.4) $ (6.6)