| Cover | Aug. 12, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Aug. 12, 2021 |
| Entity File Number | 001-39232 |
| Entity Registrant Name | RUSH STREET INTERACTIVE, INC. |
| Entity Central Index Key | 0001793659 |
| Entity Tax Identification Number | 84-3626708 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 900 N. Michigan Avenue |
| Entity Address, Address Line Two | Suite 950 |
| Entity Address, City or Town | Chicago |
| Entity Address, State or Province | IL |
| Entity Address, Postal Zip Code | 60611 |
| City Area Code | 312 |
| Local Phone Number | 915-2815 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Class A common stock, par value $0.0001 per share |
| Trading Symbol | RSI |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | true |
| Elected Not To Use the Extended Transition Period | false |
