| Document and Entity Information | Mar. 07, 2025 |
| Document Information [Line Items] | |
| Document Type | 8-K |
| Document Period End Date | Mar. 07, 2025 |
| Entity Registrant Name | WhiteHorse Finance, Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 814-00967 |
| Entity Tax Identification Number | 45-4247759 |
| Entity Address, Address Line One | 1450 Brickell Avenue |
| Entity Address, Adress Line Two | 31st Floor |
| Entity Address, City or Town | Miami |
| Entity Address State Or Province | FL |
| Entity Address, Postal Zip Code | 33131 |
| City Area Code | 305 |
| Local Phone Number | 381-6999 |
| 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 | 0001552198 |
| Amendment Flag | false |
| Common Stock [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | Common Stock, par value $0.001 per share |
| Trading Symbol | WHF |
| Security Exchange Name | NASDAQ |
| 7.875% Notes Due 2028 [Member] | |
| Document Information [Line Items] | |
| Title of 12(b) Security | 7.875% Notes due 2028 |
| Trading Symbol | WHFCL |
| Security Exchange Name | NASDAQ |
