| Document and Entity Information | May 21, 2021 |
| Document And Entity Information [Line Items] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001048268 |
| Current Fiscal Year End Date | --09-30 |
| Document Type | 8-K |
| Document Period End Date | May 21, 2021 |
| Entity Registrant Name | IES HOLDINGS, INC. |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-13783 |
| Entity Tax Identification Number | 76-0542208 |
| Entity Address, Address Line One | 5433 Westheimer Road |
| Entity Address, Address Line Two | Suite 500 |
| Entity Address, City or Town | Houston |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 77056 |
| City Area Code | (713) |
| Local Phone Number | 860-1500 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Common Stock, par value $0.01 per share |
| Trading Symbol | IESC |
| Security Exchange Name | NASDAQ |
| Preferred Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Rights to Purchase Preferred Stock |
| Trading Symbol | IESC |
| Security Exchange Name | NASDAQ |
