INVENTORIES AND SUPPLIES (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Oil and oil products	$ 70,596	$ 70,823
Supplies and drums	108,713	104,609
Solvent and solutions	10,173	10,657
Other	13,849	13,390
Total inventories and supplies	$ 203,331	$ 199,479