| Cover | Oct. 28, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Oct. 28, 2021 |
| Entity File Number | 000-50448 |
| Entity Registrant Name | Marlin Business Services Corp. |
| Entity Central Index Key | 0001260968 |
| Entity Tax Identification Number | 38-3686388 |
| Entity Incorporation, State or Country Code | PA |
| Entity Address, Address Line One | 300 Fellowship Road |
| Entity Address, City or Town | Mount Laurel |
| Entity Address, State or Province | NJ |
| Entity Address, Postal Zip Code | 08054 |
| City Area Code | 888 |
| Local Phone Number | 479-9111 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $.01 par value |
| Trading Symbol | MRLN |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | false |
