Quarterly report pursuant to Section 13 or 15(d)

DERIVATIVE INSTRUMENTS AND PRICE RISK MANAGEMENT (Details)

v2.4.1.9
DERIVATIVE INSTRUMENTS AND PRICE RISK MANAGEMENT (Details) (USD $)
In Millions, except Per Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]    
Volumes (Bbl) 3,900,000invest_DerivativeNonmonetaryNotionalAmount  
Weighted Average Price (in dollars per barrel) $ 89.66us-gaap_DerivativeSwapTypeAverageFixedPrice  
Notional volume barrels per month (in barrels) 90,000nog_DerivativeNotionalVolumeExercisablePerMonth  
Increase in derivative contracts (in barrels) 90,000nog_IncreaseInDerivativeNotionalVolumePerMonth  
Average price per barrel (in dollars per barrel) 91.00nog_DerivativeNotionalVolumeAveragePricePerMonth  
Oil Swap 1 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 180,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap1Member
 
Fixed Price (in dollars per barrel) 89.15us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap1Member
 
Oil Swap 1 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Apr. 01, 2015  
Oil Swap 1 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jun. 30, 2015  
Oil Swap 2 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 30,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap2Member
 
Fixed Price (in dollars per barrel) 90.50us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap2Member
 
Oil Swap 2 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Apr. 01, 2015  
Oil Swap 2 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jun. 30, 2015  
Oil Swap 3 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 90,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap3Member
 
Fixed Price (in dollars per barrel) 88.55us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap3Member
 
Oil Swap 3 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Apr. 01, 2015  
Oil Swap 3 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jun. 30, 2015  
Oil Swap 4 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 90,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap4Member
 
Fixed Price (in dollars per barrel) 88.00us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap4Member
 
Oil Swap 4 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Apr. 01, 2015  
Oil Swap 4 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jun. 30, 2015  
Oil Swap 5 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 30,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap5Member
 
Fixed Price (in dollars per barrel) 90.75us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap5Member
 
Oil Swap 5 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Apr. 01, 2015  
Oil Swap 5 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jun. 30, 2015  
Oil Swap 6 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 30,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap6Member
 
Fixed Price (in dollars per barrel) 90.25us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap6Member
 
Oil Swap 6 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Apr. 01, 2015  
Oil Swap 6 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jun. 30, 2015  
Oil Swap 7 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 45,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap7Member
 
Fixed Price (in dollars per barrel) 89.00us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap7Member
 
Oil Swap 7 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Apr. 01, 2015  
Oil Swap 7 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jun. 30, 2015  
Oil Swap 8 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 45,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap8Member
 
Fixed Price (in dollars per barrel) 89.00us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap8Member
 
Oil Swap 8 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Apr. 01, 2015  
Oil Swap 8 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jun. 30, 2015  
Oil Swap 9 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 540,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap9Member
 
Fixed Price (in dollars per barrel) 89.00us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap9Member
 
Oil Swap 9 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Apr. 01, 2015  
Oil Swap 9 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Dec. 31, 2015  
Oil Swap 10 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 270,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap10Member
 
Fixed Price (in dollars per barrel) 89.00us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap10Member
 
Oil Swap 10 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Apr. 01, 2015  
Oil Swap 10 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Dec. 31, 2015  
Oil Swap 11 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 270,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap11Member
 
Fixed Price (in dollars per barrel) 89.02us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap11Member
 
Oil Swap 11 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Apr. 01, 2015  
Oil Swap 11 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Dec. 31, 2015  
Oil Swap 12 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 135,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap12Member
 
Fixed Price (in dollars per barrel) 89.00us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap12Member
 
Oil Swap 12 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Apr. 01, 2015  
Oil Swap 12 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Dec. 31, 2015  
Oil Swap 13 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 135,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap13Member
 
Fixed Price (in dollars per barrel) 89.00us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap13Member
 
Oil Swap 13 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Apr. 01, 2015  
Oil Swap 13 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Dec. 31, 2015  
Oil Swap 14 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 180,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap14Member
[1]  
Fixed Price (in dollars per barrel) 90.75us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap14Member
[1]  
Oil Swap 14 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jul. 01, 2015 [1]  
Oil Swap 14 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Dec. 31, 2015 [1]  
Oil Swap 15 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 180,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap15Member
[1]  
Fixed Price (in dollars per barrel) 91.00us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap15Member
[1]  
Oil Swap 15 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jul. 01, 2015 [1]  
Oil Swap 15 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Dec. 31, 2015 [1]  
Oil Swap 16 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 180,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap16Member
[1]  
Fixed Price (in dollars per barrel) 91.25us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap16Member
[1]  
Oil Swap 16 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jul. 01, 2015 [1]  
Oil Swap 16 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Dec. 31, 2015 [1]  
Oil Swap 17 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 360,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap17Member
 
Fixed Price (in dollars per barrel) 89.00us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap17Member
 
Oil Swap 17 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jul. 01, 2015  
Oil Swap 17 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jun. 30, 2016  
Oil Swap 18 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 360,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap18Member
 
Fixed Price (in dollars per barrel) 90.00us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap18Member
 
Oil Swap 18 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jul. 01, 2015  
Oil Swap 18 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jun. 30, 2016  
Oil Swap 19 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 360,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap19Member
 
Fixed Price (in dollars per barrel) 91.00us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap19Member
 
Oil Swap 19 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jul. 01, 2015  
Oil Swap 19 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jun. 30, 2016  
Oil Swap 20 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 180,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap20Member
 
Fixed Price (in dollars per barrel) 90.00us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap20Member
 
Oil Swap 20 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jan. 01, 2016  
Oil Swap 20 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jun. 30, 2016  
Oil Swap 21 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 90,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap21Member
 
Fixed Price (in dollars per barrel) 90.00us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap21Member
 
Oil Swap 21 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jan. 01, 2016  
Oil Swap 21 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jun. 30, 2016  
Oil Swap 22 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Oil (in barrels) 90,000us-gaap_DerivativeNonmonetaryNotionalAmountVolume
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap22Member
 
Fixed Price (in dollars per barrel) 90.00us-gaap_DerivativeSwapTypeFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OilSwap22Member
 
Oil Swap 22 [Member] | Minimum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jan. 01, 2016  
Oil Swap 22 [Member] | Maximum [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Settlement Period Jun. 30, 2016  
Open Commodity Swap 1 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Volumes (Bbl) 2,970,000invest_DerivativeNonmonetaryNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OpenCommoditySwap1Member
 
Weighted Average Price (in dollars per barrel) $ 89.56us-gaap_DerivativeSwapTypeAverageFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OpenCommoditySwap1Member
 
Open Commodity Swap 2 [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Volumes (Bbl) 900,000invest_DerivativeNonmonetaryNotionalAmount
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OpenCommoditySwap2Member
 
Weighted Average Price (in dollars per barrel) $ 90.00us-gaap_DerivativeSwapTypeAverageFixedPrice
/ us-gaap_DerivativeInstrumentRiskAxis
= nog_OpenCommoditySwap2Member
 
Not Designated as Hedging Instrument [Member]    
Derivative Instruments, Gain (Loss) [Line Items]    
Realized gain (loss) on price risk derivatives not designated as hedges $ 40.0us-gaap_GainLossOnPriceRiskDerivativeInstrumentsNotDesignatedAsHedgingInstruments
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
$ (6.8)us-gaap_GainLossOnPriceRiskDerivativeInstrumentsNotDesignatedAsHedgingInstruments
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
Unrealized gain (loss) on price risk derivatives not designated as hedges $ (14.3)nog_UnrealizedGainLossOnPriceRiskDerivativesNotDesignatedAsHedges
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
$ (7.9)nog_UnrealizedGainLossOnPriceRiskDerivativesNotDesignatedAsHedges
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
[1] The Company has entered into crude oil derivative contracts that give counterparties the option to extend certain current derivative contracts for an additional six-month period. Options covering a notional volume of 90,000 barrels per month are exercisable on or about December 31, 2015. If the counterparties exercise all such options, the notional volume of the Company's existing crude oil derivative contracts will increase by 90,000 barrels per month at an average price of $ 91.00 per barrel for each month during the period January 1, 2016 through June 30, 2016.