Deposits (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Deposits [Abstract]
Interest-bearing demand	$ 578,243	$ 481,336
Money market	812,027	862,639
Savings	286,266	338,572
Retail time deposits	561,123	532,202
Wholesale non-maturity deposits	24,040	62,276
Wholesale time deposits	261,164	171,929
Total interest-bearing deposits	2,522,863	2,448,954
Noninterest-bearing deposits	834,363	924,844
Total deposits	$ 3,357,226	$ 3,373,798

The amount of retail time deposits.

No definition available.

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- Definition

Represents the amount of wholesale non-maturity deposits.

+ References

No definition available.

+ Details

Name:	bmtc_WholesaleNonmaturityDeposits
Namespace Prefix:	bmtc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Represents the amount of wholesale time deposits.

+ References

No definition available.

+ Details

Name:	bmtc_WholesaleTimeDeposits
Namespace Prefix:	bmtc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.12)
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

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- Definition

The aggregate of all domestic and foreign interest-bearing deposit liabilities.

+ References

+ Details

Name:	us-gaap_InterestBearingDepositLiabilities
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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

Amount of interest-bearing domestic checking deposit liabilities.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of interest-bearing domestic money market demand account deposit liabilities.

+ References

+ Details

Name:	us-gaap_InterestBearingDomesticDepositMoneyMarket
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

Amount of interest-bearing domestic savings deposit liabilities. Saving deposits bear interest and have no stated maturity.

+ References

+ Details

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- Definition

Amount of domestic noninterest-bearing deposits held by the entity, which may include demand deposits, checking, brokered and retail deposits.

+ References

+ Details

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Period Type:	instant