| Document and Entity Information | Feb. 23, 2021 |
| Cover [Abstract] | |
| Entity Registrant Name | COMPUTER TASK GROUP INC |
| Amendment Flag | false |
| Entity Central Index Key | 0000023111 |
| Document Type | 8-K |
| Document Period End Date | Feb. 23, 2021 |
| Entity Incorporation State Country Code | NY |
| Entity File Number | 1-9410 |
| Entity Tax Identification Number | 16-0912632 |
| Entity Address, Address Line One | 800 Delaware Avenue |
| Entity Address, City or Town | Buffalo |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 14209 |
| City Area Code | (716) |
| Local Phone Number | 882-8000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Security 12b Title | Common Stock, $.01 par value |
| Trading Symbol | CTG |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
