OTHER INCOME (EXPENSES) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
OTHER INCOME (EXPENSE)
Unrealized and realized gain (loss) on investments (note 4)	$ 925	$ (534)	$ 1,752	$ (3,269)
Foreign currency (loss) gain	(537)	1,482	(374)	2,409
Other income	75	373	132	617
Loss on sale of assets		(99)		(99)
Total other income (expense)	$ 463	$ 1,222	$ 1,510	$ (342)