INVENTORIES AND SUPPLIES (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Inventory Disclosure [Abstract]
Oil and oil related products		$ 58,142	$ 52,158
Supplies and drums		94,242	90,610
Solvent and solutions		9,167	8,566
Modular camp accommodations		1,826	15,255
Other		12,635	11,839
Total inventories and supplies		176,012	178,428
Transfer of inventory to property, plant and equipment	$ 12,600	$ 12,641	$ 0	$ 0