INVENTORIES AND SUPPLIES (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Oil and oil products	$ 39,478	$ 62,111
Supplies and drums	70,828	68,547
Solvent and solutions	10,105	9,355
Modular camp accommodations	14,703	15,776
Other	14,747	12,874
Total inventories and supplies	$ 149,861	$ 168,663