| Document And Entity Information | Nov. 07, 2024 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Nov. 07, 2024 |
| Entity Registrant Name | OneStream, Inc. |
| Entity Central Index Key | 0001889956 |
| Entity Emerging Growth Company | true |
| Entity File Number | 001-42187 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 87-3199478 |
| Entity Address, Address Line One | 191 N. Chester Street |
| Entity Address, City or Town | Birmingham |
| Entity Address, State or Province | MI |
| Entity Address, Postal Zip Code | 48009 |
| City Area Code | (248) |
| Local Phone Number | 650-1490 |
| Entity Information, Former Legal or Registered Name | Not Applicable |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Ex Transition Period | false |
| Title of 12(b) Security | Class A common stock, par value $0.0001 per share |
| Trading Symbol | OS |
| Security Exchange Name | NASDAQ |
