COMMITMENTS & CONTINGENCIES (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	63 Months Ended
Jun. 30, 2013	Jun. 30, 2013
COMMITMENTS & CONTINGENCIES [Abstract]
Estimated reversal of revenue	$ 0.1	$ 1.4

Reflects the estimated amount of revenue that may be reversed, net of production taxes, contingent upon the final judgment in the litigation.

No definition available.

Name:	nog_EstimatedReversalOfRevenue
Namespace Prefix:	nog_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration