BUSINESS SEGMENT INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Segment information:
Total revenues	$ 182,610	$ 243,777
Technical Services
Segment information:
Total revenues	172,641	227,700
Technical Services | Pressure Pumping
Segment information:
Total revenues	74,900	96,765
Technical Services | Downhole Tools
Segment information:
Total revenues	56,377	85,908
Technical Services | Coiled Tubing
Segment information:
Total revenues	14,768	16,239
Technical Services | Nitrogen
Segment information:
Total revenues	11,160	9,931
Technical Services | Snubbing
Segment information:
Total revenues	3,832	2,304
Technical Services | All other
Segment information:
Total revenues	11,604	16,553
Support Services
Segment information:
Total revenues	9,969	16,077
Support Services | Rental Tools
Segment information:
Total revenues	6,032	10,404
Support Services | All other
Segment information:
Total revenues	$ 3,937	$ 5,673