SHARE-BASED COMPENSATION PLANS - Award Plan (Details)	12 Months Ended
Dec. 31, 2018 shares day	Dec. 31, 2017 shares
Restricted Awards
Disclosure of terms and conditions of share-based payment arrangement [line items]
Vesting period	3 years
Number of trading days to determine weighted average trading price for instruments granted \| day	5
Number of instruments outstanding, beginning of period (in shares)	823,487	426,395
Number of instruments granted (in shares)	880,200	652,740
Number of instruments exercised (in shares)	(317,840)	(175,833)
Number instruments forfeited (in shares)	(202,846)	(79,815)
Number of instruments outstanding, end of period (in shares)	1,183,001	823,487
Performance Awards
Disclosure of terms and conditions of share-based payment arrangement [line items]
Number of trading days to determine weighted average trading price for instruments granted \| day	5
Forfeiture rate	5.00%
Number of instruments outstanding, beginning of period (in shares)	573,055	303,335
Number of instruments granted (in shares)	335,800	370,000
Number of instruments exercised (in shares)	(77,870)	(61,920)
Number instruments forfeited (in shares)	(67,910)	(38,360)
Number of instruments outstanding, end of period (in shares)	763,075	573,055
Bottom of range \| Restricted Awards
Disclosure of terms and conditions of share-based payment arrangement [line items]
Forfeiture rate	3.00%
Bottom of range \| Performance Awards
Disclosure of terms and conditions of share-based payment arrangement [line items]
Payout multiplier	0.00%
Top of range \| Restricted Awards
Disclosure of terms and conditions of share-based payment arrangement [line items]
Forfeiture rate	10.00%
Top of range \| Performance Awards
Disclosure of terms and conditions of share-based payment arrangement [line items]
Payout multiplier	200.00%

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

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