Accrued Interest Receivable, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
Accrued Interest Receivable, Net
Loans receivable	$ 8,532	$ 4,204
Securities	65	79
Total	8,597	4,283
Total	$ 8,597	$ 4,283

Interests earned but not yet received by the entity on its securities.

No definition available.

Name:	necb_AccruedInterestReceivableOnSecurities
Namespace Prefix:	necb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount, before allowance for credit loss, of interests earned but not yet received by the entity.

+ References

No definition available.

+ Details

Name:	necb_InterestReceivableBeforeAllowanceForCreditLoss
Namespace Prefix:	necb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Amount, before allowance for credit loss, of accrued interest on financing receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 3B
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL120267963-210447

+ Details

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

- Definition

Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3)(a)(4))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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