SEGMENT REPORTING - Total Assets by Geographical Area (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets	$ 4,106,187	$ 4,108,904
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets	3,452,839	3,413,254
Canada and other foreign
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets	$ 653,348	$ 695,650