v3.26.1
Supplemental cash flow information (Reconciliation of liabilities arising from financing activities) (Details) - CAD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Disclosure of reconciliation of liabilities arising from financing activities [line items]    
Beginning balance $ 4,236,569 $ 4,723,242
Changes from financing cash flows:    
Dividends paid (104,480) (69,641)
Interest paid (52,642) (88,818)
Shares issued, stock option plan 2,170 16,656
Lease principal payments (2,733) (2,051)
Debenture issuance   497,022
Debenture repayment   (500,000)
Term loan repayment (285,240) (541,590)
Total cash changes (442,925) (688,422)
Non-cash changes:    
Amortization of issue costs 2,721 7,342
Dividends declared 104,480 69,641
Interest expense 52,340 84,579
Right-of-use asset additions 5,366 1,100
Other 2,462 (27)
Shares issued, stock option plan 698 4,546
Foreign exchange (2,433) 34,568
Total non-cash changes 165,634 201,749
Ending balance 3,959,278 4,236,569
Long-Term Borrowings [Member]    
Disclosure of reconciliation of liabilities arising from financing activities [line items]    
Beginning balance 1,281,290 1,784,174
Changes from financing cash flows:    
Dividends paid 0 0
Interest paid 0 0
Shares issued, stock option plan 0 0
Lease principal payments 0 0
Debenture issuance   497,022
Debenture repayment   (500,000)
Term loan repayment (285,240) (541,590)
Total cash changes (285,240) (544,568)
Non-cash changes:    
Amortization of issue costs 2,721 7,342
Dividends declared 0 0
Interest expense 0  
Interest Expense On Lease Liabilities   0
Right-of-use asset additions 0 0
Other 0 0
Shares issued, stock option plan 0 0
Foreign exchange (2,423) 34,342
Total non-cash changes 298 41,684
Ending balance 996,348 1,281,290
Interest Payable [Member]    
Disclosure of reconciliation of liabilities arising from financing activities [line items]    
Beginning balance 10,073 14,087
Changes from financing cash flows:    
Dividends paid 0 0
Interest paid (52,130) (88,333)
Shares issued, stock option plan 0 0
Lease principal payments 0 0
Debenture issuance   0
Debenture repayment   0
Term loan repayment 0 0
Total cash changes (52,130) (88,333)
Non-cash changes:    
Amortization of issue costs 0 0
Dividends declared 0 0
Interest expense 51,828 84,094
Right-of-use asset additions 0 0
Other 0 0
Shares issued, stock option plan 0 0
Foreign exchange (9) 225
Total non-cash changes 51,819 84,319
Ending balance 9,762 10,073
Lease Obligation [Member]    
Disclosure of reconciliation of liabilities arising from financing activities [line items]    
Beginning balance 9,839 10,816
Changes from financing cash flows:    
Dividends paid 0 0
Interest paid (512) (485)
Shares issued, stock option plan 0 0
Lease principal payments (2,733) (2,051)
Debenture issuance   0
Debenture repayment   0
Term loan repayment 0 0
Total cash changes (3,245) (2,536)
Non-cash changes:    
Amortization of issue costs 0 0
Dividends declared 0 0
Interest Expense On Lease Liabilities 512 485
Right-of-use asset additions 5,366 1,100
Other 2,462 (27)
Shares issued, stock option plan 0 0
Foreign exchange (1) 1
Total non-cash changes 8,339 1,559
Ending balance 14,933 9,839
Dividends Payable [Member]    
Disclosure of reconciliation of liabilities arising from financing activities [line items]    
Beginning balance 0 0
Changes from financing cash flows:    
Dividends paid (104,480) (69,641)
Interest paid 0 0
Shares issued, stock option plan 0 0
Lease principal payments 0 0
Debenture issuance   0
Debenture repayment   0
Term loan repayment 0 0
Total cash changes (104,480) (69,641)
Non-cash changes:    
Amortization of issue costs 0 0
Dividends declared 104,480 69,641
Interest expense 0  
Interest Expense On Lease Liabilities   0
Right-of-use asset additions 0 0
Other 0 0
Shares issued, stock option plan 0 0
Foreign exchange 0 0
Total non-cash changes 104,480 69,641
Ending balance 0 0
Share Capital [Member]    
Disclosure of reconciliation of liabilities arising from financing activities [line items]    
Beginning balance 2,935,367 2,914,165
Changes from financing cash flows:    
Dividends paid 0 0
Interest paid 0 0
Shares issued, stock option plan 2,170 16,656
Lease principal payments 0 0
Debenture issuance   0
Debenture repayment   0
Term loan repayment 0 0
Total cash changes 2,170 16,656
Non-cash changes:    
Amortization of issue costs 0 0
Dividends declared 0 0
Interest expense 0  
Interest Expense On Lease Liabilities   0
Right-of-use asset additions 0 0
Other 0 0
Shares issued, stock option plan 698 4,546
Foreign exchange 0 0
Total non-cash changes 698 4,546
Ending balance $ 2,938,235 $ 2,935,367