EARNINGS PER SHARE (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Earnings Per Share [Abstract]
Net income	$ 29,638	$ 20,685	[1],[2]
Less: Income attributable to redeemable noncontrolling interest	(195)	(224)	[2]
Net income attributable to CSW Industrials, Inc.	$ 29,443	$ 20,461	[2]
Weighted average shares:
Common stock (in shares)	15,541	15,605
Participating securities (in shares)	102	110
Denominator for basic earnings per common share (in shares)	15,643	15,715	[2]
Potentially dilutive securities (in shares)	9	66
Denominator for diluted earnings per common share (in shares)	15,652	15,781	[2]
Net income per share attributable to CSW Industrials, Inc. shareholders:
Basic (USD per share)	$ 1.88	$ 1.30	[2]
Diluted (USD per share)	$ 1.88	$ 1.30	[2]

[1] *Prior period has been adjusted to reflect the change in inventory accounting method, as described in the Company's fiscal 2022 Annual Report on Form 10-K

[2] Prior period has been adjusted to reflect the change in inventory accounting method, as described in the Company's fiscal 2022 Annual Report on Form 10-K.