XML 42 R67.htm IDEA: XBRL DOCUMENT v2.4.1.9
Note 8 - Employee Benefit Plans (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Note 8 - Employee Benefit Plans (Details) [Line Items]      
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent 100.00%us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent    
Defined Contribution Plan, Employer Discretionary Contribution Amount $ 273us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount $ 282us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount $ 279us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Age Attained to Be Eligible for ESOP 21 years    
Employee Stock Ownership Plan (ESOP), Cash Contributions to ESOP 100us-gaap_EmployeeStockOwnershipPlanESOPCashContributionsToESOP 275us-gaap_EmployeeStockOwnershipPlanESOPCashContributionsToESOP 370us-gaap_EmployeeStockOwnershipPlanESOPCashContributionsToESOP
Employee Stock Ownership Plan (ESOP), Number of Allocated Shares (in Shares) 246,370us-gaap_EmployeeStockOwnershipPlanESOPNumberOfAllocatedShares    
Age of Employees Required to Diversify Allocated ESOP Shares 55 years    
Years of Plan Participation Required to Diversify Allocated ESOP Shares 10 years    
Percentage of Allocated ESOP Shares That Can Be Diversified 50.00%nksh_PercentageOfAllocatedEsopSharesThatCanBeDiversified    
Accrued Expenses for Salary Continuation Plan $ 246nksh_AccruedExpensesForSalaryContinuationPlan $ 194nksh_AccruedExpensesForSalaryContinuationPlan $ 151nksh_AccruedExpensesForSalaryContinuationPlan
Equity Securities [Member]      
Note 8 - Employee Benefit Plans (Details) [Line Items]      
Defined Benefit Plan, Target Plan Asset Allocations 65.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_EquitySecuritiesMember
   
Fixed Income Securities [Member]      
Note 8 - Employee Benefit Plans (Details) [Line Items]      
Defined Benefit Plan, Target Plan Asset Allocations 35.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_FixedIncomeSecuritiesMember
   
Hedge Funds [Member]      
Note 8 - Employee Benefit Plans (Details) [Line Items]      
Defined Benefit Plan, Target Plan Asset Allocations 0.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_HedgeFundsMember
   
Private Equity Funds [Member]      
Note 8 - Employee Benefit Plans (Details) [Line Items]      
Defined Benefit Plan, Target Plan Asset Allocations 0.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_PrivateEquityFundsMember
   
Real Estate [Member]      
Note 8 - Employee Benefit Plans (Details) [Line Items]      
Defined Benefit Plan, Target Plan Asset Allocations 0.00%us-gaap_DefinedBenefitPlanTargetPlanAssetAllocations
/ us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis
= us-gaap_RealEstateMember