RENTAL INCOME (Rent Receivable) (Details) - USD ($)	Mar. 31, 2021	Dec. 31, 2020
RENTAL INCOME
Allowance for doubtful rent receivable	$ 1,271,000	$ 1,454,000
Recognizing rental income from non-cancelable commercial leases with future rental increases on a straight-line basis	84,000
Deferred rental concession	$ 427,000

Represents the amount resulting from recognizing rental income from non-cancelable commercial leases with future rental increases on a straight-line basis, which is included in rents receivable.

No definition available.

Name:	nen_OperatingLeasesRentalIncomeWithFutureRentalIncreases
Namespace Prefix:	nen_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant