INCOME TAXES - Net Deferred Tax Assets (Liabilites) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Tax Credit Carryforward [Line Items]
Net deferred tax assets	$ 5,122	$ 3,701
Net deferred tax liability	0	(55)
Bolivia
Tax Credit Carryforward [Line Items]
Net deferred tax assets	1,368	1,467
Canada
Tax Credit Carryforward [Line Items]
Net deferred tax assets	0	0
Colombia
Tax Credit Carryforward [Line Items]
Net deferred tax assets	2,249	1,735
Malaysia
Tax Credit Carryforward [Line Items]
Net deferred tax assets	233
Net deferred tax liability		(55)
Peru
Tax Credit Carryforward [Line Items]
Net deferred tax assets	$ 1,272	$ 554