Document and Entity Information
| Document and Entity Information Document | Mar. 09, 2020 |
| Cover page. | |
| Document Type | 8-K |
| Document Period End Date | Mar. 9, 2020 |
| Entity Registrant Name | SP PLUS CORP |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 000-50796 |
| Entity Tax Identification Number | 16-1171179 |
| Entity Address, Address Line One | 200 E. Randolph Street, Suite 7700 |
| Entity Address, City or Town | Chicago |
| Entity Address, State or Province | IL |
| Entity Address, Postal Zip Code | 60601‑7702 |
| City Area Code | 312 |
| Local Phone Number | 274-2000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Title of 12(b) Security | Common Stock, $0.001 par value per share |
| Trading Symbol | SP |
| Security Exchange Name | NASDAQ |
| Entity Central Index Key | 0001059262 |
| Amendment Flag | false |