XML 13 R48.htm IDEA: XBRL DOCUMENT
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Note 8 - Fair Value Measurements (Details) - Level 3 Fair Value Measurements | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2015 | Dec. 31, 2014
Present Value of Cash Flows [Member] | Impaired loans [Member] | Minimum [Member] |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |  |  |
Discount rate | 5.88%us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_ImpairedLoansMember / us-gaap_RangeAxis = us-gaap_MinimumMember / us-gaap_ValuationTechniqueAxis = nksh_PresentValueOfCashFlowsMember |  | 5.88%us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_ImpairedLoansMember / us-gaap_RangeAxis = us-gaap_MinimumMember / us-gaap_ValuationTechniqueAxis = nksh_PresentValueOfCashFlowsMember |
Discount rate weighted average | (5.88%)us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_ImpairedLoansMember / us-gaap_RangeAxis = us-gaap_MinimumMember / us-gaap_ValuationTechniqueAxis = nksh_PresentValueOfCashFlowsMember |  | (5.88%)us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_ImpairedLoansMember / us-gaap_RangeAxis = us-gaap_MinimumMember / us-gaap_ValuationTechniqueAxis = nksh_PresentValueOfCashFlowsMember |
Present Value of Cash Flows [Member] | Impaired loans [Member] | Maximum [Member] |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |  |  |
Discount rate | 9.50%us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_ImpairedLoansMember / us-gaap_RangeAxis = us-gaap_MaximumMember / us-gaap_ValuationTechniqueAxis = nksh_PresentValueOfCashFlowsMember |  | 9.50%us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_ImpairedLoansMember / us-gaap_RangeAxis = us-gaap_MaximumMember / us-gaap_ValuationTechniqueAxis = nksh_PresentValueOfCashFlowsMember |
Discount rate weighted average | (9.50%)us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_ImpairedLoansMember / us-gaap_RangeAxis = us-gaap_MaximumMember / us-gaap_ValuationTechniqueAxis = nksh_PresentValueOfCashFlowsMember |  | (9.50%)us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_ImpairedLoansMember / us-gaap_RangeAxis = us-gaap_MaximumMember / us-gaap_ValuationTechniqueAxis = nksh_PresentValueOfCashFlowsMember |
Present Value of Cash Flows [Member] | Impaired loans [Member] | Weighted Average [Member] |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |  |  |
Discount rate | 6.11%us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_ImpairedLoansMember / us-gaap_RangeAxis = us-gaap_WeightedAverageMember / us-gaap_ValuationTechniqueAxis = nksh_PresentValueOfCashFlowsMember |  | 6.15%us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_ImpairedLoansMember / us-gaap_RangeAxis = us-gaap_WeightedAverageMember / us-gaap_ValuationTechniqueAxis = nksh_PresentValueOfCashFlowsMember |
Discount rate weighted average | (6.11%)us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_ImpairedLoansMember / us-gaap_RangeAxis = us-gaap_WeightedAverageMember / us-gaap_ValuationTechniqueAxis = nksh_PresentValueOfCashFlowsMember |  | (6.15%)us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_ImpairedLoansMember / us-gaap_RangeAxis = us-gaap_WeightedAverageMember / us-gaap_ValuationTechniqueAxis = nksh_PresentValueOfCashFlowsMember |
Present Value of Cash Flows [Member] | Impaired loans [Member] |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |  |  |
Valuation Technique | Present value of cash flows |  | Present value of cash flows |
Discounted Appraised Value [Member] | Impaired loans [Member] |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |  |  |
Valuation Technique | Discounted appraised value |  | Discounted appraised value |
Selling cost | 10.00%nksh_FairValueInputsSellingCostRate / us-gaap_FairValueByAssetClassAxis = nksh_ImpairedLoansMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |  | 10.00%nksh_FairValueInputsSellingCostRate / us-gaap_FairValueByAssetClassAxis = nksh_ImpairedLoansMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |
Selling cost weighted average | (10.00%)nksh_FairValueInputsSellingCostRate / us-gaap_FairValueByAssetClassAxis = nksh_ImpairedLoansMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |  | (10.00%)nksh_FairValueInputsSellingCostRate / us-gaap_FairValueByAssetClassAxis = nksh_ImpairedLoansMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |
Discounted Appraised Value [Member] | Other Real Estate Owned [Member] | Minimum [Member] |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |  |  |
Discount rate | 3.76%us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_MinimumMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |  | 0.00%us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_MinimumMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |
Discount rate weighted average | (3.76%)us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_MinimumMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |  | 0.00%us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_MinimumMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |
Selling cost | 0.00%nksh_FairValueInputsSellingCostRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_MinimumMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember | [1] | 0.00%nksh_FairValueInputsSellingCostRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_MinimumMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember | [1]
Selling cost weighted average | 0.00%nksh_FairValueInputsSellingCostRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_MinimumMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember | [1] | 0.00%nksh_FairValueInputsSellingCostRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_MinimumMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember | [1]
Discounted Appraised Value [Member] | Other Real Estate Owned [Member] | Maximum [Member] |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |  |  |
Discount rate | 48.77%us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_MaximumMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |  | 48.77%us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_MaximumMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |
Discount rate weighted average | (48.77%)us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_MaximumMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |  | (48.77%)us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_MaximumMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |
Selling cost | 11.00%nksh_FairValueInputsSellingCostRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_MaximumMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |  | 11.00%nksh_FairValueInputsSellingCostRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_MaximumMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |
Selling cost weighted average | (11.00%)nksh_FairValueInputsSellingCostRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_MaximumMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |  | (11.00%)nksh_FairValueInputsSellingCostRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_MaximumMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |
Discounted Appraised Value [Member] | Other Real Estate Owned [Member] | Weighted Average [Member] |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |  |  |
Discount rate | 14.64%us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_WeightedAverageMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |  | 20.81%us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_WeightedAverageMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |
Discount rate weighted average | (14.64%)us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_WeightedAverageMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |  | (20.81%)us-gaap_FairValueInputsDiscountRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_WeightedAverageMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |
Selling cost | 9.13%nksh_FairValueInputsSellingCostRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_WeightedAverageMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |  | 8.60%nksh_FairValueInputsSellingCostRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_WeightedAverageMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |
Selling cost weighted average | (9.13%)nksh_FairValueInputsSellingCostRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_WeightedAverageMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |  | (8.60%)nksh_FairValueInputsSellingCostRate / us-gaap_FairValueByAssetClassAxis = nksh_OtherRealEstateOwnedMember / us-gaap_RangeAxis = us-gaap_WeightedAverageMember / us-gaap_ValuationTechniqueAxis = nksh_DiscountedAppraisedValueMember |
Discounted Appraised Value [Member] | Other Real Estate Owned [Member] |  |  |  |
Fair Value Inputs, Assets, Quantitative Information [Line Items] |  |  |  |
Valuation Technique | Discounted appraised value |  | Discounted appraised value |
[1] | The Company markets other real estate owned both independently and with local realtors. Properties marketed by realtors are discounted by selling costs. Properties that the Company markets independently are not discounted by selling costs.

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- Definition Refers to the rate of selling cost. + References No definition available. + Details
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- Definition Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb) -URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258 + Details
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- Definition Description of the inputs and valuation technique(s) used to measure fair value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb) -URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258 + Details
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