INCOME TAXES - Schedule of Capital Losses and Net Operating Losses (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Operating Loss Carryforwards [Line Items]
Net operating losses expected to expire	$ 75,000
Capital losses | United States
Operating Loss Carryforwards [Line Items]
Amount	52,591
Disallowed Interest
Operating Loss Carryforwards [Line Items]
Amount	353
CANADA | Non-capital losses | Canada
Operating Loss Carryforwards [Line Items]
Amount	37,018
CANADA | Capital losses | Canada
Operating Loss Carryforwards [Line Items]
Amount	3,293
CANADA | Investment Tax Credits | Canada
Operating Loss Carryforwards [Line Items]
Amount	1,213
Pre-2018 Net operating losses | UNITED STATES | United States
Operating Loss Carryforwards [Line Items]
Amount	250,370
Post-2017 Net Operating losses | UNITED STATES | United States
Operating Loss Carryforwards [Line Items]
Amount	$ 15,949