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v3.20.4

Shares - Common shares (Details) - CAD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019
Increase (Decrease) in Stockholders' Equity [Roll Forward] |  |
Beginning balance, outstanding (in shares) | 25,777,445 | 25,004,205
Issued upon exercise of stock options (in shares) | 109,100 | 327,000
Issued upon conversion of convertible debentures (in shares) | 4,622,916 | 87,096
Retired through share purchase programs (in shares) | (1,223,097) |
Purchase of treasury shares (in shares) | (907,462) | (735,857)
Settlement of certain equity classified stock-based compensation (in shares) | 787,728 | 1,095,001
Ending balance, outstanding (in shares) | 29,166,630 | 25,777,445
Shares to satisfy recipient tax withholding requirements (in shares) | 372,628,000 | 513,540,000
Satisfaction of recipient tax withholding | $ 3,576 | $ 7,246
Common shares |  |
Increase (Decrease) in Stockholders' Equity [Roll Forward] |  |
Beginning balance, outstanding (in shares) | 27,502,912 | 27,088,816
Issued upon exercise of stock options (in shares) | 109,100 | 327,000
Issued upon conversion of convertible debentures (in shares) | 4,622,916 | 87,096
Retired through share purchase programs (in shares) | (1,223,097) |
Purchase of treasury shares (in shares) | 0 | 0
Settlement of certain equity classified stock-based compensation (in shares) | 0 | 0
Ending balance, outstanding (in shares) | 31,011,831 | 27,502,912
Treasury shares |  |
Increase (Decrease) in Stockholders' Equity [Roll Forward] |  |
Beginning balance, outstanding (in shares) | (1,725,467) | (2,084,611)
Issued upon exercise of stock options (in shares) | 0 | 0
Issued upon conversion of convertible debentures (in shares) | 0 | 0
Retired through share purchase programs (in shares) | 0 |
Purchase of treasury shares (in shares) | (907,462) | (735,857)
Settlement of certain equity classified stock-based compensation (in shares) | 787,728 | 1,095,001
Ending balance, outstanding (in shares) | (1,845,201) | (1,725,467)

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