| Cover | Nov. 15, 2024 |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Nov. 15, 2024 |
| Entity File Number | 001-37503 |
| Entity Registrant Name | B. Riley FinanCIAl, Inc. |
| Entity Central Index Key | 0001464790 |
| Entity Tax Identification Number | 27-0223495 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 11100 Santa Monica Blvd. |
| Entity Address, Address Line Two | Suite 800 |
| Entity Address, City or Town | Los Angeles |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 90025 |
| City Area Code | 310 |
| Local Phone Number | 966-1444 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Stock, par value $0.0001 per share | |
| Title of 12(b) Security | Common Stock, par value $0.0001 per share |
| Trading Symbol | RILY |
| Security Exchange Name | NASDAQ |
| Depositary Shares (each representing a 1/1000th interest in a 6.875% Series A Cumulative Perpetual Preferred Share, par value $0.0001 per share) | |
| Title of 12(b) Security | Depositary Shares (each representing a 1/1000th interest in a 6.875% Series A Cumulative Perpetual Preferred Share, par value $0.0001 per share) |
| Trading Symbol | RILYP |
| Security Exchange Name | NASDAQ |
| Depositary Shares, each representing a 1/1000th fractional interest in a 7.375% share of Series B Cumulative Perpetual Preferred Stock | |
| Title of 12(b) Security | Depositary Shares, each representing a 1/1000th fractional interest in a 7.375% share of Series B Cumulative Perpetual Preferred Stock |
| Trading Symbol | RILYL |
| Security Exchange Name | NASDAQ |
| 6.375% Senior Notes due 2025 | |
| Title of 12(b) Security | 6.375% Senior Notes due 2025 |
| Trading Symbol | RILYM |
| Security Exchange Name | NASDAQ |
| 5.00% Senior Notes due 2026 | |
| Title of 12(b) Security | 5.00% Senior Notes due 2026 |
| Trading Symbol | RILYG |
| Security Exchange Name | NASDAQ |
| 5.50% Senior Notes due 2026 | |
| Title of 12(b) Security | 5.50% Senior Notes due 2026 |
| Trading Symbol | RILYK |
| Security Exchange Name | NASDAQ |
| 6.50% Senior Notes due 2026 | |
| Title of 12(b) Security | 6.50% Senior Notes due 2026 |
| Trading Symbol | RILYN |
| Security Exchange Name | NASDAQ |
| 5.25% Senior Notes due 2028 | |
| Title of 12(b) Security | 5.25% Senior Notes due 2028 |
| Trading Symbol | RILYZ |
| Security Exchange Name | NASDAQ |
| 6.00% Senior Notes due 2028 | |
| Title of 12(b) Security | 6.00% Senior Notes due 2028 |
| Trading Symbol | RILYT |
| Security Exchange Name | NASDAQ |
