XML 17 R54.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Note 5 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans (Details) - Ratios for Allowance for Loan Losses | 12 Months Ended
--- | ---
Dec. 31, 2014 | Dec. 31, 2013
Ratios for Allowance for Loan Losses [Abstract] |  |
Ratio of allowance for loan losses to the end of period loans, net of unearned income and deferred fees | 1.36%nksh_RatioOfAllowanceForLoanLossesToEndOfPeriodLoans | 1.38%nksh_RatioOfAllowanceForLoanLossesToEndOfPeriodLoans
Ratio of net charge-offs to average loans, net of unearned income and deferred fees | 0.27%nksh_RatioOfNetChargeOffsToAverageLoans | 0.28%nksh_RatioOfNetChargeOffsToAverageLoans

X
- Definition Represents ratio of allowance for loan losses to the end of period loans, net of unearned income and deferred fees. + References No definition available. + Details
Name: | nksh_RatioOfAllowanceForLoanLossesToEndOfPeriodLoans
Namespace Prefix: | nksh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents ratio of net charge-offs to average loans, net of unearned income and deferred fees. + References No definition available. + Details
Name: | nksh_RatioOfNetChargeOffsToAverageLoans
Namespace Prefix: | nksh_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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