| Document and Entity Information Document | Sep. 30, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | Sep. 30, 2020 |
| Entity Registrant Name | PCB BANCORP |
| Entity Central Index Key | 0001423869 |
| Amendment Flag | false |
| Entity Incorporation, State or Country Code | CA |
| Entity File Number | 001-38621 |
| Entity Tax Identification Number | 20-8856755 |
| Entity Address, Address Line One | 3701 Wilshire Boulevard |
| Entity Address, Address Line Two | Suite 900 |
| Entity Address, City or Town | Los Angeles |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 90010 |
| City Area Code | 213 |
| Local Phone Number | 210-2000 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common stock, no par value |
| Trading Symbol | PCB |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | true |
