Annual report pursuant to Section 13 and 15(d)

Employees' Benefit Plans (Details Textual)

v2.4.1.9
Employees' Benefit Plans (Details Textual) (USD $)
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Defined Benefit Plan Disclosure [Line Items]    
Eligibility Of Employees Employees are eligible to participate in the Employees’ Savings and Profit Sharing Plan and Trust on the next January 1 or July 1 following the completion of one year of employment, age 18, and completion of 1,000 hours of service.  
Deferred Fee Liability $ 1,300,000nwin_DeferredFeeLiability $ 1,260,000nwin_DeferredFeeLiability
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay 8.00%us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent 9.00%us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Defined Contribution Plan, Cost Recognized 599,000us-gaap_DefinedContributionPlanCostRecognized 636,000us-gaap_DefinedContributionPlanCostRecognized
Deferred Compensation Liability, Current and Noncurrent 171,000us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent 156,000us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent
Deferred Compensation Arrangement with Individual, Compensation Expense 15,000us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense 15,000us-gaap_DeferredCompensationArrangementWithIndividualCompensationExpense
Deferred Costs $ 106,000us-gaap_DeferredCostsCurrentAndNoncurrent $ 96,000us-gaap_DeferredCostsCurrentAndNoncurrent
Trust for Benefit of Employees [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Description of Defined Contribution Pension and Other Postretirement Plans Participants also become 100% vested in the employer contributions and accrued earnings in their account upon their death, approved disability, or attainment of age 65 while employed at the Bank.  
Two Years Of Service [Member] | Trust for Benefit of Employees [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Defined Benefit Plan, Funded Percentage 40.00%us-gaap_DefinedBenefitPlanFundedPercentage
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= nwin_TwoYearsOfServiceMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_TrustForBenefitOfEmployeesMember 		 
Three Years Of Service [Member] | Trust for Benefit of Employees [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Defined Benefit Plan, Funded Percentage 60.00%us-gaap_DefinedBenefitPlanFundedPercentage
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= nwin_ThreeYearsOfServiceMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_TrustForBenefitOfEmployeesMember 		 
Four Years Of Service [Member] | Trust for Benefit of Employees [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Defined Benefit Plan, Funded Percentage 80.00%us-gaap_DefinedBenefitPlanFundedPercentage
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= nwin_FourYearsOfServiceMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_TrustForBenefitOfEmployeesMember 		 
Five Years Of Service [Member] | Trust for Benefit of Employees [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Defined Benefit Plan, Funded Percentage 100.00%us-gaap_DefinedBenefitPlanFundedPercentage
/ us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis
= nwin_FiveYearsOfServiceMember
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= us-gaap_TrustForBenefitOfEmployeesMember 		 
Maximum [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Defined Benefit Plan Employees Pre Tax Contributions 50.00%nwin_DefinedBenefitPlanEmployeesPreTaxContributions
/ us-gaap_RangeAxis
= us-gaap_MaximumMember 		 
Minimum [Member]    
Defined Benefit Plan Disclosure [Line Items]    
Defined Benefit Plan Employees Pre Tax Contributions 1.00%nwin_DefinedBenefitPlanEmployeesPreTaxContributions
/ us-gaap_RangeAxis
= us-gaap_MinimumMember