XML 107 R33.htm IDEA: XBRL DOCUMENT
v2.4.0.8

Note 4 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans (Details) - Summary of Nonperforming Assets (USD $) In Thousands, unless otherwise specified | Jun. 30, 2013 | Dec. 31, 2012 | Jun. 30, 2012
--- | --- | --- | ---
Summary of Nonperforming Assets [Abstract] |  |  |  |  |  |
Nonaccrual loans | $ 10,428 |  | $ 10,870 |  | $ 3,627 |
Restructured loans in nonaccrual | 1,522 |  | 2,151 |  | 3,763 |
Total nonperforming loans | 11,950 |  | 13,021 |  | 7,390 |
Other real estate owned, net | 969 |  | 1,435 |  | 871 |
Total nonperforming assets | $ 12,919 |  | $ 14,456 |  | $ 8,261 |
Ratio of nonperforming assets to loans, net of unearned income and deferred fees, plus other real estate owned | 2.19% |  | 2.44% |  | 1.41% |
Ratio of allowance for loan losses to nonperforming loans(1) | 66.54% | [1] | 64.12% | [1] | 110.53% | [1]
[1] | The Company defines nonperforming loans as nonaccrual loans. Loans 90 days or more past due and still accruing and accruing restructured loans are excluded.

X
- Definition Reflects the percentage derived from dividing the nonperforming assets by total loans net of unearned income deferred fees plus other real estate owned. + References No definition available. + Details
Name: | nksh_AssetsRatioOfNonperformingAssetsToLoansNetOfUnearnedIncomeAndDeferredFeesPlusOreo
Namespace Prefix: | nksh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Recorded investment in non-restructured loans that are on nonaccrual status as of the balance sheet date. + References No definition available. + Details
Name: | nksh_LoanReceivableNonaccrual
Namespace Prefix: | nksh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Refers to restructured loans in nonaccrual. + References No definition available. + Details
Name: | nksh_NonaccrualRestructuredLoans
Namespace Prefix: | nksh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Represents financing receivables that are in nonaccrual status and other real estate owned. + References No definition available. + Details
Name: | nksh_NonperformingAssets
Namespace Prefix: | nksh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Refers to ratio of allowance for loan losses to nonperforming loans. + References No definition available. + Details
Name: | nksh_RatioOfAllowanceForLoanLossesToNonperformingLoans
Namespace Prefix: | nksh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | nksh_SummaryOfNonperformingAssetsAbstract
Namespace Prefix: | nksh_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

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 (d) -URI http://asc.fasb.org/extlink&oid=28368275&loc=d3e5111-111524 + Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Carrying amount as of the balance sheet date of land and buildings obtained through foreclosure proceedings or defeasance in full or partial satisfaction of a debt arrangement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4437-111522 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 28 -Article 12 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph c -Subparagraph Schedule III -Article 5 + Details
Name: | us-gaap_RealEstateAcquiredThroughForeclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant