SHARE-BASED COMPENSATION - Summary of DSU activity (Details) - Deferred share units - shares shares in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of units, beginning of period (in shares)	1,018	1,146
Grants (in shares)	150	105
Exercises (in shares)	(82)	(233)
Number of units, end of period (in shares)	1,086	1,018

Line items represent concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes of the table.

No definition available.

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- Definition

The number of other equity instruments (ie other than share options) granted in a share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Name IFRS
-Number 2
-IssueDate 2018-01-01
-Paragraph 47
-Subparagraph b
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2018-03-01&anchor=para_47_b&doctype=Standard
-URIDate 2018-03-16

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 2
-IssueDate 2018-01-01
-Paragraph 45
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-URIDate 2018-03-16

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- Definition

The number of other equity instruments (ie other than share options) exercised or vested in a share-based payment arrangement.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IFRS
-Number 2
-IssueDate 2018-01-01
-Paragraph 45
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IFRS&num=2&date=2018-03-01&anchor=para_45&doctype=Standard
-URIDate 2018-03-16

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- Definition

The number of other equity instruments (ie other than share options) outstanding in a share-based payment arrangement.

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