ADVANCE RENTAL PAYMENTS AND SECURITY DEPOSITS (Details) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
ADVANCE RENTAL PAYMENTS AND SECURITY DEPOSITS
Period for advance rental payment	1 month
Amount received for prepaid rent	$ 1,568,000	$ 1,448,000
Security deposits	$ 2,332,000	$ 2,286,000

Represents amounts received from tenants for prepaid rents which are included in cash and cash equivalents.

No definition available.

Name:	nen_PrepaidRentReceivedIncludedInCashAndCashEquivalents
Namespace Prefix:	nen_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant