Document and Entity Information - shares	9 Months Ended
	Dec. 31, 2016	Feb. 06, 2017
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2017
Document Fiscal Period Focus	Q3
Trading Symbol	CSWI
Entity Registrant Name	CSW INDUSTRIALS, INC.
Entity Central Index Key	0001624794
Current Fiscal Year End Date	--03-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		15,848,117