SEGMENT REPORTING (Total Assets by Geographical Area) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets	$ 3,882,054	$ 3,738,321
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets	3,212,979	3,090,311
Canada
Revenues from External Customers and Long-Lived Assets [Line Items]
Total assets	$ 669,075	$ 648,010