CASH AND CASH EQUIVALENTS AND RESTRICTED CASH (Details) $ in Thousands, $ in Millions					12 Months Ended
	Dec. 20, 2018 CAD ($)	Dec. 20, 2018 USD ($)	Dec. 20, 2017 USD ($)	Sep. 22, 2017 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 19, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Cash and cash equivalents (note 21)					$ 15,756	$ 27,153
Restricted cash					14,685	10,000
Restricted cash included in other long-term assets					48
Total cash, cash equivalents, and restricted cash					30,489	37,153		$ 37,440	$ 25,874
Net proceeds				$ 43,200	918	39,397
Generative exploration activities					14,700	0
Common Stock
Net proceeds					918	39,397
Flow Through Common Shares
Restricted cash					0		$ 10,000
Net proceeds	$ 20.0	$ 14,900	$ 14,900		$ 11,145	$ 7,799