INVENTORIES AND SUPPLIES (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Oil and oil products	$ 46,671	$ 33,603
Supplies and drums	78,168	78,132
Solvent and solutions	8,756	8,868
Modular camp accommodations	15,298	15,126
Other	13,511	13,792
Total inventories and supplies	$ 162,404	$ 149,521