NONCONTROLLING INTERESTS - Effect of Changes (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Effects of changes in noncontrolling interests on equity
Net income (loss) attributable to Select Energy Services, Inc.	$ (44,298)	$ 6,200	$ (290,160)	$ 7,335
Transfers (to) from noncontrolling interests:
Noncontrolling interest in subsidiary	$ 133		133
Increase in additional paid-in capital as a result of restricted stock issuance, net of forfeitures			1,911	3,540
Increase in additional paid-in capital as a result of issuance of common stock due to vesting of restricted stock units			1	4
(Decrease) increase in additional paid-in capital as a result of the repurchase of SES Holdings LLC Units			(1,405)	(25)
Increase in additional paid-in capital as a result of the Employee Stock Purchase Plan shares issued			4	2
Change to equity from net income attributable to Select Energy Services, Inc. and transfers from noncontrolling interests			$ (289,649)	$ 10,856
SES Holdings LLC [Member]
Transfers (to) from noncontrolling interests:
Noncontrolling Interest	50.00%		50.00%

This element represents the total net income attributable to the parent for the period and the effect of net changes during the period impacting the parent's ownership interest in a subsidiary as it relates to the total (consolidated) equity attributable to the parent. The changes to the parent's ownership interest in a subsidiary represented by this element did not result in a deconsolidation of the subsidiary from the consolidated financial statements.

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