| Document And Entity Information | Mar. 10, 2021 |
| Document Information [Line Items] | |
| Entity, Registrant Name | Bryn Mawr Bank Corporation |
| Document, Type | 8-K |
| Document, Period End Date | Mar. 10, 2021 |
| 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 |
| Written Communications | false |
| Soliciting Material | true |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $1 par value |
| Trading Symbol | BMTC |
| Security Exchange Name | NASDAQ |
| Entity, Emerging Growth Company | false |
| Amendment Flag | false |
| Entity, Central Index Key | 0000802681 |
