INCOME (LOSS) PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Calculation of basic and diluted earnings per share:
Net income (loss)	$ 14,581	$ (19,615)	$ 22,566	$ (47,036)
Net income (loss) attributable to noncontrolling interests	(2,078)	3,048	(3,261)	7,362
Net income (loss) attributable to Select Energy Services, Inc.	12,503	(16,567)	19,305	(39,674)
Add: Reallocation of net income (loss) attributable to noncontrolling interests for the dilutive effect of restricted stock	18		34
Add: Reallocation of net income (loss) attributable to noncontrolling interests for the dilutive effect of performance units	12		18
Net income (loss) attributable to Select Energy Services, Inc. - diluted	$ 12,533	$ (16,567)	$ 19,357	$ (39,674)
Class A Common Stock
Calculation of basic and diluted earnings per share:
Antidilutive shares	1,846,578	2,132,690	1,846,578	2,132,690
Net income (loss) attributable to Select Energy Services, Inc.	$ 12,503	$ (16,567)	$ 19,305	$ (39,674)
Add: Reallocation of net income (loss) attributable to noncontrolling interests for the dilutive effect of restricted stock	18		34
Add: Reallocation of net income (loss) attributable to noncontrolling interests for the dilutive effect of performance units	12		18
Net income (loss) attributable to Select Energy Services, Inc. - diluted	$ 12,533	$ (16,567)	$ 19,357	$ (39,674)
Weighted-average shares of common stock outstanding - basic	93,833,504	85,244,439	92,833,593	85,118,851
Dilutive effect of restricted stock	904,023		1,099,937
Dilutive effect of performance share units	618,282		573,490
Dilutive effect of ESPP	80		157
Weighted-average shares of common stock outstanding - diluted	95,355,889	85,244,439	94,507,178	85,118,851
Income (loss) per share, Basic (in dollars per share)	$ 0.13	$ (0.19)	$ 0.21	$ (0.47)
Income (loss) per share, Diluted (in dollars per share)	$ 0.13	$ (0.19)	$ 0.20	$ (0.47)
Class B Common Stock
Calculation of basic and diluted earnings per share:
Weighted-average shares of common stock outstanding - basic	16,221,101	16,221,101	16,221,101	16,221,101
Weighted-average shares of common stock outstanding - diluted	16,221,101	16,221,101	16,221,101	16,221,101