Fair Value Measurements - Balance Sheet Grouping (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Carrying Amount
Financial assets:
Loans held for sale	$ 476	$ 601
Loans, net	2,644,163	2,531,845
Financial liabilities:
Borrowed Funds	84,169	96,173
Subordinated debt	14,876	14,872
Carrying Amount \| Certificates of deposit
Financial liabilities:
Certificates of deposit	302,108	310,951
Fair Value
Financial assets:
Loans held for sale	476	609
Loans, net	2,695,924	2,542,577
Financial liabilities:
Borrowed Funds	84,212	96,045
Subordinated debt	15,969	14,957
Fair Value \| Certificates of deposit
Financial liabilities:
Certificates of deposit	305,405	311,975
Fair Value, Inputs, Level 1
Financial assets:
Loans held for sale	0	0
Loans, net	0	0
Financial liabilities:
Borrowed Funds	0	0
Subordinated debt	0	0
Fair Value, Inputs, Level 1 \| Certificates of deposit
Financial liabilities:
Certificates of deposit	0	0
Fair Value, Inputs, Level 2
Financial assets:
Loans held for sale	476	609
Loans, net	0	0
Financial liabilities:
Borrowed Funds	84,212	96,045
Subordinated debt	0	0
Fair Value, Inputs, Level 2 \| Certificates of deposit
Financial liabilities:
Certificates of deposit	305,405	311,975
Fair Value, Inputs, Level 3
Financial assets:
Loans held for sale	0	0
Loans, net	2,695,924	2,542,577
Financial liabilities:
Borrowed Funds	0	0
Subordinated debt	15,969	14,957
Fair Value, Inputs, Level 3 \| Certificates of deposit
Financial liabilities:
Certificates of deposit	$ 0	$ 0

Other borrowings

No definition available.

Name:	ebtc_BorrowedFundsFairValueDisclosure
Namespace Prefix:	ebtc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

+ References

No definition available.

+ Details

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

- Definition

Fair value of subordinated debt obligations including, but not limited to, subordinated loan, subordinated bond, subordinated debenture or junior debt.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

+ Details

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

- References

No definition available.

+ Details

Name:	us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Fair value portion of loans held-for-sale including, but not limited to, mortgage loans and finance receivables.

+ References

No definition available.

+ Details

Name:	us-gaap_LoansHeldForSaleFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

+ Details

Name:	us-gaap_LoansReceivableFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ebtc_DepositTypeAxis=us-gaap_CertificatesOfDepositMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_EstimateOfFairValueFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: