ASSET RETIREMENT OBLIGATIONS (Details) $ in Thousands, $ in Millions	12 Months Ended
Dec. 31, 2018 CAD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Reclamation obligations
Reclamation Adjustment		$ 2,259	$ 1,426	$ 89
Remediation Accretion		1,205	635	506
Reclamation and remediation expense		3,464	2,061	595
Changes in the asset retirement obligations
Asset retirement obligation, beginning of the period		24,722	9,843
Settlements		(392)	(126)
Accretion of liability		1,205	635
Acquisitions and divestitures			11,803
Adjustment reflecting updated estimates		5,024	2,561
Foreign exchange revaluation		(1,157)	6
Asset retirement obligation, ending balance		29,402	24,722	$ 9,843
Current portion		(734)	(646)
Non-current portion		28,668	$ 24,076
Black Fox
Mineral Property Interests
Surety bonding obligation	$ 20.6	15,900
Changes in the asset retirement obligations
Asset retirement obligation, ending balance		11,200
Gold Bar project
Changes in the asset retirement obligations
Adjustment reflecting updated estimates		$ 3,700

Mineral Property Interests [Line Items]

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Amount of reclamation adjustments during the period.

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Amount of reclamation and remediation expenses.

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Represents a surety bond obligation. It is a promise by a surety or guarantor to pay one party (the obligee) a certain amount if a second party (the principal) fails to meet some obligation, such as fulfilling the terms of a contract.

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Amount recognized for the passage of time, typically for liabilities, that have been discounted to their net present values. Excludes accretion associated with asset retirement obligations.

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The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability.

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Current portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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Amount of foreign currency translation gain (loss) which decreases (increases) asset retirement obligations.

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Amount of asset retirement obligations incurred during the period.

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Amount of asset retirement obligations settled, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset.

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Amount of increase (decrease) in the asset retirement obligation from changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Noncurrent portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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