| Cover | Jan. 21, 2021 | Jan. 16, 2020 |
| Cover [Abstract] | ||
| Document Type | 8-K | |
| Document Period End Date | Jan. 21, 2021 | |
| Entity Registrant Name | Bryn Mawr Bank Corporation | |
| Entity Central Index Key | 0000802681 | |
| Amendment Flag | false | |
| Entity Incorporation, State or Country Code | PA | |
| Entity File Number | 001-35746 | |
| Entity Tax Identification Number | 23-2434506 | |
| Entity Address, Address Line One | 801 Lancaster Avenue | |
| Entity Address, City or Town | Bryn Mawr | |
| Entity Address, State or Province | PA | |
| Entity Address, Postal Zip Code | 19010 | |
| City Area Code | 610 | |
| Local Phone Number | 525-1700 | |
| Title of 12(b) Security | Common Stock, $1 par value | |
| Trading Symbol | BMTC | |
| Security Exchange Name | NASDAQ | |
| Written Communications | false | |
| Soliciting Material | false | |
| Pre-commencement Tender Offer | false | |
| Pre-commencement Issuer Tender Offer | false | |
| Entity Emerging Growth Company | false |
