Asset Retirement Obligations - Changes In Asset Retirement Obligations (Details) - CAD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020
Reconciliation of changes in other provisions [Abstract]
Accretion	$ 12,381	$ 8,978
Government grants	(2,857)	(2,128)
Less current portion of asset retirement obligations	11,080	11,820
Non-current portion of asset retirement obligations	732,603	748,563
Asset retirement obligation
Reconciliation of changes in other provisions [Abstract]
Balance, beginning of the year	760,383	667,974
Liabilities incurred	14,845	15,189
Liabilities settled	(6,662)	(7,168)
Liabilities acquired from property acquisitions	249	0
Liabilities divested	(3,161)	(721)
Property swaps	(4,113)	(525)
Accretion	12,381	8,978
Government grants	(2,857)	(2,128)
Change in estimate	(9,686)	(12,771)
Changes in discount rates and inflation rates	(17,381)	92,576
Foreign currency translation	(315)	(1,021)
Balance, end of the year	$ 743,683	$ 760,383

Adjustments For Other Income

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Increase (decrease) through change in estimate, other provisions

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Property Swaps

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The increase in other provisions resulting from acquisitions through business combinations. [Refer: Business combinations [member]; Other provisions]

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The decrease in other provisions resulting from the loss of control of a subsidiary. [Refer: Other provisions]

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The amount of expense recognised due to the unwinding of the discount on provisions other than provisions from employee benefits, resulting from the effect of the passage of time. [Refer: Other provisions]

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The increase (decrease) in other provisions resulting from a change in discount rate. [Refer: Other provisions]

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The increase (decrease) in other provisions resulting from foreign currency exchange rate changes on provisions measured in a currency different from the entity's presentation currency. [Refer: Other provisions]

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The amount of non-current provision for decommissioning, restoration and rehabilitation costs. [Refer: Provision for decommissioning, restoration and rehabilitation costs]

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The amount recognised for new other provisions. [Refer: Other provisions]

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The amount of provisions other than provisions for employee benefits. [Refer: Provisions]

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The amount used (ie incurred and charged against the provision) for other provisions. [Refer: Other provisions]

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The amount of current provision for decommissioning, restoration and rehabilitation costs. [Refer: Provision for decommissioning, restoration and rehabilitation costs]

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