INVENTORIES AND SUPPLIES (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Oil and oil products	$ 67,888	$ 70,823
Supplies and drums	108,976	104,609
Solvent and solutions	10,500	10,657
Other	13,450	13,390
Total inventories and supplies	$ 200,814	$ 199,479