BUSINESS SEGMENT INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment information:
Total revenues	$ 188,757	$ 89,300	$ 371,367	$ 333,077
Technical Services
Segment information:
Total revenues	176,119	80,532	348,760	308,232
Technical Services | Pressure Pumping
Segment information:
Total revenues	72,179	23,717	147,079	120,481
Technical Services | Downhole Tools
Segment information:
Total revenues	58,853	35,151	115,230	121,059
Technical Services | Coiled Tubing
Segment information:
Total revenues	20,399	8,973	35,167	25,212
Technical Services | Nitrogen
Segment information:
Total revenues	8,039	5,621	19,199	15,553
Technical Services | Snubbing
Segment information:
Total revenues	3,105	1,093	6,937	3,397
Technical Services | All other
Segment information:
Total revenues	13,544	5,977	25,148	22,530
Support Services
Segment information:
Total revenues	12,638	8,768	22,607	24,845
Support Services | Rental Tools
Segment information:
Total revenues	8,549	5,069	14,581	15,475
Support Services | All other
Segment information:
Total revenues	$ 4,089	$ 3,699	$ 8,026	$ 9,370