IMPAIRMENT OF LONG‑LIVED ASSETS (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment Reporting Information [Line Items]
Property and equipment impairment expense	$ 0	$ 6,305,000	$ 36,609,000
Net carrying value of property and equipment	$ 470,910,000	263,862,000
Drilling
Segment Reporting Information [Line Items]
Property and equipment impairment expense		6,300,000	28,600,000
Net carrying value of property and equipment		15,000,000
Fair value of the reporting unit			18,800,000
Acidizing unit
Segment Reporting Information [Line Items]
Property and equipment impairment expense			8,000,000
Fair value of the reporting unit			$ 6,300,000
Estimated fair value measurements | Significant other observable inputs (Level 2) | Drilling
Segment Reporting Information [Line Items]
Property and equipment, net		$ 8,700,000