| Cover | Dec. 22, 2023 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Dec. 22, 2023 |
| Entity Registrant Name | MSC Income Fund, Inc. |
| Entity Incorporation, State or Country Code | MD |
| Securities Act File Number | 814-00939 |
| Entity Tax Identification Number | 45-3999996 |
| Entity Address, Address Line One | 1300 Post Oak Boulevard |
| Entity Address, Address Line Two | 8th Floor |
| Entity Address, City or Town | Houston |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 77056 |
| City Area Code | 713 |
| Local Phone Number | 350-6000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0001535778 |
| Amendment Flag | false |
