| Cover | Jun. 27, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Jun. 27, 2022 |
| Entity Registrant Name | CSW INDUSTRIALS, INC. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 001-37454 |
| Entity Tax Identification Number | 47-2266942 |
| Entity Address, Address Line One | 5420 Lyndon B. Johnson Freeway, Suite 500 |
| Entity Address, City or Town | Dallas |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 75240 |
| City Area Code | 214 |
| Local Phone Number | 884-3777 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.01 per share |
| Trading Symbol | CSWI |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001624794 |
| Amendment Flag | false |
