Cover
| Cover | Mar. 29, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Mar. 29, 2021 |
| Entity File Number | 001-38671 |
| Entity Registrant Name | CAPITAL BANCORP, INC. |
| Entity Central Index Key | 0001419536 |
| Entity Tax Identification Number | 52-2083046 |
| Entity Incorporation, State or Country Code | MD |
| Entity Address, Address Line One | 2275 Research Boulevard |
| Entity Address, Address Line Two | Suite 600 |
| Entity Address, City or Town | Rockville |
| Entity Address, State or Province | MD |
| Entity Address, Postal Zip Code | 20850 |
| City Area Code | 301 |
| Local Phone Number | 468-8848 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.01 per share |
| Trading Symbol | CBNK |
| Security Exchange Name | NASDAQ |
| Entity Emerging Growth Company | true |
| Elected Not To Use the Extended Transition Period | true |