SEGMENT REPORTING - Schedule of Non-current Assets Excluding Deferred Tax Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Non-current assets, excluding deferred tax assets	$ 98,850	$ 98,299
Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Non-current assets, excluding deferred tax assets	41,870	42,947
U.S. [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Non-current assets, excluding deferred tax assets	$ 56,980	$ 55,352