v3.25.3
Share-based payments - Disclosure of information concerning outstanding stock options (Details)
 12 Months Ended
Sep. 30, 2025
shares
$ / shares
Sep. 30, 2024
shares
$ / shares
Share-Based Payment Arrangements [Abstract]    
Outstanding, beginning of year (in shares) | shares 3,862,527 5,211,472
Exercised (in shares) | shares (947,071) (1,333,876)
Forfeited (in shares) | shares 0 (12,575)
Expired (in shares) | shares (2,983) (2,494)
Outstanding, end of year (in shares) | shares 2,912,473 3,862,527
Exercisable, end of year (in shares) | shares 2,912,473 3,699,805
Outstanding, beginning of year (in CAD per share) | $ / shares $ 74.53 $ 70.21
Excercised (in CAD per share) | $ / shares 65.45 57.38
Forfeited (in CAD per share) | $ / shares 0 97.84
Expired (in CAD per share) | $ / shares 84.91 98.65
Outstanding, end of year (in CAD per share) | $ / shares 77.48 74.53
Excercisable (in CAD per share) | $ / shares $ 77.48 $ 73.51