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Share Capital (Narrative) (Details) $ / shares in Units, $ / shares in Units, $ in Millions, $ in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Jun. 30, 2024 USD ($) shares | Jun. 30, 2024 CAD ($) shares | Dec. 31, 2024 USD ($) shares $ / shares | Dec. 31, 2024 $ / shares shares | Dec. 31, 2023 USD ($) shares $ / shares | Dec. 31, 2023 $ / shares
Equity Financing [Line Items] |  |  |  |  |  |
Stock Repurchased Authorization | shares |  |  | 18,605,661 | 18,605,661 |  |
Shares repurchased and cancelled (in shares) | shares | 451,990 | 451,990 | 0 |  | 0 |
Proceeds from issuance of flow-through shares | $ 10.5 | $ 14.4 | $ 10.5 |  | $ 0.0 |
Dividends paid | $ |  |  | $ 35.1 |  | $ 35.3 |
Weighted average share price for share options in share-based payment arrangement exercised during period at date of exercise | $ / shares |  |  |  | $ 22.92 |  | $ 16.82
Granted (in shares) | shares |  |  | 471,177 |  | 481,449 |
Share price (cad per share) | $ / shares |  |  |  | $ 26.52 |  | $ 17.74
Top of range |  |  |  |  |  |
Equity Financing [Line Items] |  |  |  |  |  |
Discount rate on prevailing market price from treasury |  |  | 5.00% |  |  |
Restricted share units ("RSU") |  |  |  |  |  |
Equity Financing [Line Items] |  |  |  |  |  |
Weighted average exercise price of other equity instruments granted in share-based payment arrangement | $ / shares |  |  | $ 16.41 |  | $ 14.07 |
Deferred share units ("DSU") |  |  |  |  |  |
Equity Financing [Line Items] |  |  |  |  |  |
Weighted average exercise price of other equity instruments granted in share-based payment arrangement | $ / shares |  |  | 16.75 |  | 14.35 |
Performance share units ("PSU") |  |  |  |  |  |
Equity Financing [Line Items] |  |  |  |  |  |
Weighted average exercise price of other equity instruments granted in share-based payment arrangement | $ / shares |  |  | $ 16.07 |  | $ 14.10 |
SHARE CAPITAL |  |  |  |  |  |
Equity Financing [Line Items] |  |  |  |  |  |
Dividend reinvestment plan and share purchase plan (in shares) | shares |  |  | 349,088 |  | 353,084 |
Shares issued during period, value, DRIP | $ |  |  | $ 5.8 |  | $ 4.1 |
Dividends recognised as distributions to owners | $ |  |  |  |  | $ 4.1 |
Shares issued through share purchase plan (in shares) | shares |  |  | 401,537 |  | 469,566 |
DEFICIT |  |  |  |  |  |
Equity Financing [Line Items] |  |  |  |  |  |
Dividends recognised as distributions to owners | $ |  |  | $ 40.9 |  | $ 39.4 |

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