Quarterly report pursuant to Section 13 or 15(d)

Fair Value (Details Textual)

v2.4.1.9
Fair Value (Details Textual) (USD $)
Mar. 31, 2015
Dec. 31, 2014
Fair Value [Line Items]    
Minimum Percentage of Defaults Rates on Above 3 Years Issuer Average in Other than Temporary Impairment Model Assumptions 0.25%nwin_MinimumPercentageOfDefaultsRatesOnAbove3YearsIssuerAverageInOtherThanTemporaryImpairmentModelAssumptions  
Maximum Percentage of Defaults Rates on Above 3 Years Issuer Average in Other than Temporary Impairment Model Assumptions 5.00%nwin_MaximumPercentageOfDefaultsRatesOnAbove3YearsIssuerAverageInOtherThanTemporaryImpairmentModelAssumptions  
Minimum Percentage of Recovery Assumptions on Other than Temporary Impairment Model Assumptions 0.00%nwin_MinimumPercentageOfRecoveryAssumptionsOnOtherThanTemporaryImpairmentModelAssumptions  
Maximum Percentage of Recovery Assumptions on Other than Temporary Impairment Model Assumptions 15.00%nwin_MaximumPercentageOfRecoveryAssumptionsOnOtherThanTemporaryImpairmentModelAssumptions  
Available-for-sale Securities, Amortized Cost Basis $ 3,900,000us-gaap_AvailableForSaleSecuritiesAmortizedCost  
Unpaid Principal Balance 6,800,000us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance 7,300,000us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance
Impaired Financing Receivable, Reserve 487,000nwin_ImpairedFinancingReceivableReserve 426,000nwin_ImpairedFinancingReceivableReserve
Impaired Financing Receivable, Fair Value $ 6,400,000nwin_ImpairedFinancingReceivableFairValue $ 6,900,000nwin_ImpairedFinancingReceivableFairValue