Long-term financial assets (Details) - CAD ($) |
Sep. 30, 2025 |
Sep. 30, 2024 |
|---|---|---|
| Subclassifications of assets, liabilities and equities [abstract] | ||
| Deferred compensation plan assets | $ 125,388,000 | $ 112,270,000 |
| Long-term investments | 27,687,000 | 24,209,000 |
| Long-term receivables | 8,509,000 | 10,114,000 |
| Long-term derivative financial instruments | 854,000 | 2,644,000 |
| Long-term financial assets | $ 162,438,000 | $ 149,237,000 |