| Cover | Nov. 29, 2024 |
| Cover [Abstract] | |
| Entity Registrant Name | PROSPECT CAPITAL CORPORATION |
| Entity Address, Address Line One | 10 East 40th Street |
| Entity Address, City or Town | New York |
| Entity Address, Address Line Two | 42nd Floor |
| Entity Address, State or Province | NY |
| Entity Address, Postal Zip Code | 10016 |
| Entity Central Index Key | 0001287032 |
| Amendment Flag | false |
| Document Type | POS EX |
| City Area Code | 212 |
| Local Phone Number | 448-0702 |
| Contact Personnel Name | John F. Barry III |
| No Substantive Changes, 462(c) | false |
| Exhibits Only, 462(d) | true |
| Entity Emerging Growth Company | false |
| Entity Well-known Seasoned Issuer | Yes |
