| Cover | Mar. 24, 2022 |
| Document Information [Line Items] | |
| Document Type | 8-K/A |
| Amendment Flag | true |
| Document Period End Date | Mar. 24, 2022 |
| Entity Registrant Name | Southwest Gas Holdings, Inc. |
| Entity File Number | 001-37976 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 81-3881866 |
| Entity Address, Address Line One | 8360 S. Durango Drive |
| Entity Address, Address Line Two | Post Office Box 98510 |
| Entity Address, City or Town | Las Vegas |
| Entity Address, State or Province | NV |
| Entity Address, Postal Zip Code | 89193 |
| City Area Code | 702 |
| Local Phone Number | 876-7237 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001692115 |
| Amendment Description | EXPLANATORY NOTE This Amendment No. 1 (this “Amendment”) to the Current Report on Form 8-K filed by Southwest Gas Holdings, Inc. and its subsidiary Southwest Gas Corporation (the “Company”) on March 28, 2022 (the “Initial Filing”) is being filed to update certain information regarding the timing of the retirement of Eric DeBonis and the appointment of Julie M. Williams as the Senior Vice President/Operations of the Company. Except as set forth in this Amendment, the information included in the Initial Filing remains unchanged. |
| Common Stock [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Southwest Gas Holdings, Inc. Common Stock, $1 par value |
| Trading Symbol | SWX |
| Security Exchange Name | NYSE |
| Preferred Stock Purchase Rights [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Preferred Stock Purchase Rights |
| No Trading Symbol Flag | true |
| Security Exchange Name | NYSE |
| Southwest Gas Corporation [Member] | |
| Document Information [Line Items] | |
| Amendment Flag | true |
| Entity Registrant Name | Southwest Gas Corporation |
| Entity File Number | 001-07850 |
| Entity Incorporation, State or Country Code | CA |
| Entity Tax Identification Number | 88-0085720 |
| Entity Address, Address Line One | 8360 S. Durango Drive |
| Entity Address, Address Line Two | Post Office Box 98510 |
| Entity Address, City or Town | Las Vegas |
| Entity Address, State or Province | NV |
| Entity Address, Postal Zip Code | 89193 |
| City Area Code | 702 |
| Local Phone Number | 876-7237 |
| Entity Central Index Key | 0000092416 |
