| Cover - USD ($) | 12 Months Ended | ||
| Dec. 31, 2022 | Mar. 27, 2023 | Jul. 01, 2022 | |
| Cover [Abstract] | |||
| Document Type | 10-K/A | ||
| Amendment Flag | true | ||
| Amendment Description | On March 31, 2023, Williams Industrial Services Group Inc. ("Williams," the "Company," "we," "us," or "our") filed its Annual Report on Form 10-K for the fiscal year ended December 31, 2022 (the "Original Form 10-K") with the U.S. Securities and Exchange Commission (the "SEC"). We are filing this Annual Report on Form 10-K/A (this "Amendment") as Amendment No. 1 to the Original Form 10-K for the purposes of amending Part III, Items 10, 11, 12, 13 and 14 of the Original Form 10-K to include the information required by such Items. This information was previously omitted from the Original Form 10-K in reliance on General Instruction G(3) to Form 10-K. This Amendment amends and restates in their entirety Items 10, 11, 12, 13 and 14 of Part III of the Original Form 10-K. | ||
| Document Annual Report | true | ||
| Document Transition Report | false | ||
| Document Period End Date | Dec. 31, 2022 | ||
| Document Fiscal Period Focus | FY | ||
| Document Fiscal Year Focus | 2022 | ||
| Current Fiscal Year End Date | --12-31 | ||
| Entity File Number | 001-16501 | ||
| Entity Registrant Name | Williams Industrial Services Group Inc. | ||
| Entity Central Index Key | 0001136294 | ||
| Entity Tax Identification Number | 73-1541378 | ||
| Entity Incorporation, State or Country Code | DE | ||
| Entity Address, Address Line One | 200 Ashford Center North | ||
| Entity Address, Address Line Two | Suite 425 | ||
| Entity Address, City or Town | Atlanta | ||
| Entity Address, State or Province | GA | ||
| Entity Address, Postal Zip Code | 30338 | ||
| City Area Code | 770 | ||
| Local Phone Number | 879-4400 | ||
| Title of 12(b) Security | Common Stock, par value $0.01 per share | ||
| Trading Symbol | WLMS | ||
| Security Exchange Name | NYSE | ||
| Entity Well-known Seasoned Issuer | No | ||
| Entity Voluntary Filers | No | ||
| Entity Current Reporting Status | Yes | ||
| Entity Interactive Data Current | Yes | ||
| Entity Filer Category | Non-accelerated Filer | ||
| Entity Small Business | true | ||
| Entity Emerging Growth Company | false | ||
| Entity Shell Company | false | ||
| Entity Public Float | $ 23,197,687 | ||
| Entity Common Stock, Shares Outstanding | 27,058,317 | ||
| ICFR Auditor Attestation Flag | false | ||
| Auditor Name | Moss Adams LLP | ||
| Auditor Location | Dallas, Texas | ||
| Auditor Firm ID | 659 |
