XML 44 R33.htm IDEA: XBRL DOCUMENT
v3.7.0.1

Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Past Due and Nonaccrual Loans (Details) - USD ($) $ in Thousands | Jun. 30, 2017 | Dec. 31, 2016 | Jun. 30, 2016
--- | --- | --- | ---
Nonaccruals (including impaired nonaccruals) |  | $ 3,197 | [1],[2] | $ 5,855 | [1],[2] | $ 6,205
Loans past due 90 days or more and still accruing |  | 259 | [2] | 63 | [2] | $ 316
Consumer Real Estate Portfolio Segment [Member] | Equity Lines [Member] |  |  |  |  |  |
Nonaccruals (including impaired nonaccruals) | [1],[2] | 0 |  | 0 |  |
Loans past due 90 days or more and still accruing | [2] | 0 |  | 0 |  |
Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member] |  |  |  |  |  |
Nonaccruals (including impaired nonaccruals) | [1],[2] | 0 |  | 0 |  |
Loans past due 90 days or more and still accruing | [2] |  |  | 6 |  |
Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member] |  |  |  |  |  |
Nonaccruals (including impaired nonaccruals) | [1],[2] | 0 |  | 0 |  |
Loans past due 90 days or more and still accruing | [2] |  |  | 36 |  |
Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member] |  |  |  |  |  |
Nonaccruals (including impaired nonaccruals) | [1],[2] | 271 |  | 253 |  |
Loans past due 90 days or more and still accruing | [2] | 0 |  | 0 |  |
Real Estate Construction Portfolio Segment[Member] | Construction Residential [Member] |  |  |  |  |  |
Nonaccruals (including impaired nonaccruals) | [1],[2] |  |  | 270 |  |
Loans past due 90 days or more and still accruing | [2] |  |  | 0 |  |
Real Estate Construction Portfolio Segment[Member] | Construction, Other [Member] |  |  |  |  |  |
Nonaccruals (including impaired nonaccruals) | [1],[2] |  |  | 0 |  |
Loans past due 90 days or more and still accruing | [2] |  |  | 0 |  |
Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member] |  |  |  |  |  |
Nonaccruals (including impaired nonaccruals) | [1],[2] | 0 |  | 1,091 |  |
Loans past due 90 days or more and still accruing | [2] | 0 |  | 0 |  |
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member] |  |  |  |  |  |
Nonaccruals (including impaired nonaccruals) | [1],[2] | 133 |  | 1,183 |  |
Loans past due 90 days or more and still accruing | [2] | 0 |  | 0 |  |
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member] |  |  |  |  |  |
Nonaccruals (including impaired nonaccruals) | [1],[2] | 2,655 |  | 2,814 |  |
Loans past due 90 days or more and still accruing | [2] | 0 |  | 0 |  |
Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member] |  |  |  |  |  |
Nonaccruals (including impaired nonaccruals) | [1],[2] | 136 |  |  |  |
Loans past due 90 days or more and still accruing | [2] | 200 |  |  |  |
Consumer Non Real Estate Portfolio Segment [Member] | Credit Card Receivable [Member] |  |  |  |  |  |
Nonaccruals (including impaired nonaccruals) | [1],[2] | 0 |  | 0 |  |
Loans past due 90 days or more and still accruing | [2] | 5 |  | 5 |  |
Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member] |  |  |  |  |  |
Nonaccruals (including impaired nonaccruals) | [1],[2] | 2 |  | 3 |  |
Loans past due 90 days or more and still accruing | [2] | 33 |  | 12 |  |
Consumer Non Real Estate Portfolio Segment [Member] | Other Consumer Loans [Member] |  |  |  |  |  |
Nonaccruals (including impaired nonaccruals) | [1],[2] | 0 |  | 0 |  |
Loans past due 90 days or more and still accruing | [2] | 21 |  | 4 |  |
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] |  |  |  |  |  |
Nonaccruals (including impaired nonaccruals) | [1],[2] |  |  | 241 |  |
Loans past due 90 days or more and still accruing | [2] |  |  | 0 |  |
Financing Receivables 30 to 89 Days Past Due [Member] |  |  |  |  |  |
Past due loans | [2] | 1,988 |  | 2,553 |  |
Financing Receivables 30 to 89 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Equity Lines [Member] |  |  |  |  |  |
Past due loans | [2] | 91 |  | 10 |  |
Financing Receivables 30 to 89 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member] |  |  |  |  |  |
Past due loans | [2] | 901 |  | 1,498 |  |
Financing Receivables 30 to 89 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member] |  |  |  |  |  |
Past due loans | [2] | 185 |  | 114 |  |
Financing Receivables 30 to 89 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member] |  |  |  |  |  |
Past due loans | [2] | 165 |  | 56 |  |
Financing Receivables 30 to 89 Days Past Due [Member] | Real Estate Construction Portfolio Segment[Member] | Construction Residential [Member] |  |  |  |  |  |
Past due loans | [2] |  |  | 0 |  |
Financing Receivables 30 to 89 Days Past Due [Member] | Real Estate Construction Portfolio Segment[Member] | Construction, Other [Member] |  |  |  |  |  |
Past due loans | [2] |  |  | 25 |  |
Financing Receivables 30 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member] |  |  |  |  |  |
Past due loans | [2] | 57 |  | 132 |  |
Financing Receivables 30 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member] |  |  |  |  |  |
Past due loans | [2] | 122 |  | 339 |  |
Financing Receivables 30 to 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member] |  |  |  |  |  |
Past due loans | [2] | 0 |  | 0 |  |
Financing Receivables 30 to 89 Days Past Due [Member] | Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member] |  |  |  |  |  |
Past due loans | [2] | 258 |  |  |  |
Financing Receivables 30 to 89 Days Past Due [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Credit Card Receivable [Member] |  |  |  |  |  |
Past due loans | [2] | 2 |  | 8 |  |
Financing Receivables 30 to 89 Days Past Due [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member] |  |  |  |  |  |
Past due loans | [2] | 132 |  | 234 |  |
Financing Receivables 30 to 89 Days Past Due [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Other Consumer Loans [Member] |  |  |  |  |  |
Past due loans | [2] | 75 |  | 131 |  |
Financing Receivables 30 to 89 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] |  |  |  |  |  |
Past due loans | [2] |  |  | 6 |  |
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] |  |  |  |  |  |
Past due loans | [2] | 518 |  | 1,888 |  |
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Equity Lines [Member] |  |  |  |  |  |
Past due loans | [2] | 0 |  | 0 |  |
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Closed End First Liens [Member] |  |  |  |  |  |
Past due loans | [2] |  |  | 6 |  |
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Closed End Junior Liens [Member] |  |  |  |  |  |
Past due loans | [2] |  |  | 36 |  |
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Real Estate Portfolio Segment [Member] | Investor Owned Residential Real Estate [Member] |  |  |  |  |  |
Past due loans | [2] | 8 |  | 234 |  |
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real Estate Construction Portfolio Segment[Member] | Construction Residential [Member] |  |  |  |  |  |
Past due loans | [2] |  |  | 0 |  |
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Real Estate Construction Portfolio Segment[Member] | Construction, Other [Member] |  |  |  |  |  |
Past due loans | [2] |  |  | 0 |  |
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Multifamily Real Estate [Member] |  |  |  |  |  |
Past due loans | [2] |  |  | 1,091 |  |
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate, Owner Occupied [Member] |  |  |  |  |  |
Past due loans | [2] | 133 |  | 202 |  |
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Other [Member] |  |  |  |  |  |
Past due loans | [2] | 0 |  | 80 |  |
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Non Real Estate Segment [Member] | Commercial and Industrial [Member] |  |  |  |  |  |
Past due loans | [2] | 318 |  |  |  |
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Credit Card Receivable [Member] |  |  |  |  |  |
Past due loans | [2] | 5 |  | 5 |  |
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Automobile Loan [Member] |  |  |  |  |  |
Past due loans | [2] | 33 |  | 12 |  |
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Consumer Non Real Estate Portfolio Segment [Member] | Other Consumer Loans [Member] |  |  |  |  |  |
Past due loans | [2] | $ 21 |  | 4 |  |
Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member] |  |  |  |  |  |
Past due loans | [2] |  |  | $ 218 |  |
[1] | Includes current and past due loans in nonaccrual status. Includes impaired loans in nonaccrual status.
[2] | Only classes with past-due or nonaccrual loans are shown.

X
- Definition Recorded investment in financing receivables that are 90 days or more past due and still accruing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5111-111524 + Details
Name: | us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5111-111524 + Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Recorded Investment in financing receivables that are past due at the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 7A -URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953401-111524 + Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentPastDue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=nksh_ConsumerRealEstatePortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_EquityLinesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_ClosedEndFirstLiensMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_ClosedEndJuniorLiensMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_InvestorOwnedResidentialRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=nksh_RealEstateConstructionPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_ConstructionResidentialMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_ConstructionOtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_MultifamilyRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_CommercialRealEstateOwnerOccupiedMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_CommercialRealEstateOtherMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=nksh_CommercialNonRealEstateSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_CommercialAndIndustrialMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=nksh_ConsumerNonRealEstatePortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CreditCardReceivablesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_AutomobileLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=nksh_OtherConsumerLoansMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=nksh_FinancingReceivables30To89DaysPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |