Name:	necb_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLossFeeLoanInProcessAndUnfundedCommitments
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Number of bank branch offices through which bank conduct business.

No definition available.

Name:	necb_NumberOfBranchOffice
Namespace Prefix:	necb_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Number of loan production offices of the bank.

No definition available.

Name:	necb_NumberOfLoanProductionOffice
Namespace Prefix:	necb_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Number of properties owned.

No definition available.

Name:	necb_NumberOfPropertiesOwned
Namespace Prefix:	necb_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Percentage of loan that is concentrated as construction loan.

No definition available.

Name:	necb_PercentageOfConstructionLoan
Namespace Prefix:	necb_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Percentage of increase in finance receivable during the reporting period.

No definition available.

Name:	necb_PercentageOfIncreaseInFinanceReceivable
Namespace Prefix:	necb_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	necb_SummaryOfSignificantAccountingPoliciesLineItems
Namespace Prefix:	necb_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amortized cost excluding accrued interest, after allowance for credit loss, of financing receivable. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

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

The increase (decrease) during the reporting period in outstanding loans including accrued interest.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 28
-Subparagraph (a)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-28

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

Name:	srt_StatementGeographicalAxis=necb_BronxMember
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Balance Type:
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Name:	srt_StatementGeographicalAxis=necb_OrangeCountyMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	srt_StatementGeographicalAxis=necb_RocklandCountyMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	srt_StatementGeographicalAxis=necb_SullivanCountyMember
Namespace Prefix:
Data Type:	na
Balance Type:
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Name:	srt_StatementGeographicalAxis=necb_RocklandOrangeAndSullivanCountyMember
Namespace Prefix:
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