SEGMENT REPORTING (Geographical Information) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets	$ 4,152,539	$ 4,131,520
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets	3,472,053	3,447,811
Canada and other foreign
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets	$ 680,486	$ 683,709