BUSINESS SEGMENT INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment information:
Total revenues	$ 243,777	$ 334,656
Technical Services
Segment information:
Total revenues	227,700	314,079
Technical Services | Pressure Pumping
Segment information:
Total revenues	96,765	147,759
Technical Services | Downhole Tools
Segment information:
Total revenues	85,908	109,671
Technical Services | Coiled Tubing
Segment information:
Total revenues	16,239	20,178
Technical Services | Nitrogen
Segment information:
Total revenues	9,931	11,308
Technical Services | Snubbing
Segment information:
Total revenues	2,304	3,463
Technical Services | All other
Segment information:
Total revenues	16,553	21,700
Support Services
Segment information:
Total revenues	16,077	20,577
Support Services | Rental Tools
Segment information:
Total revenues	10,404	13,936
Support Services | All other
Segment information:
Total revenues	$ 5,673	$ 6,641