| Document and Entity Information | Dec. 13, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Dec. 13, 2021 |
| Entity Registrant Name | J.JILL, INC. |
| Entity Central Index Key | 0001687932 |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | false |
| Entity File Number | 001-38026 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 45-1459825 |
| Entity Address, Address Line One | 4 Batterymarch Park |
| Entity Address, City or Town | Quincy |
| Entity Address, State or Province | MA |
| Entity Address, Postal Zip Code | 02169 |
| City Area Code | 617 |
| Local Phone Number | 376-4300 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.01 par value |
| Trading Symbol | JILL |
| Security Exchange Name | NYSE |
