INVENTORIES AND SUPPLIES (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Oil and oil products	$ 36,196	$ 33,603
Supplies and drums	79,035	78,132
Solvent and solutions	9,026	8,868
Modular camp accommodations	15,438	15,126
Other	15,073	13,792
Total inventories and supplies	$ 154,768	$ 149,521