XML 41 R30.htm IDEA: XBRL DOCUMENT
v3.4.0.3

Note 4 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Ratios of Allowance for Loan Losses (Details) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2016 | Mar. 31, 2015 | Dec. 31, 2015
Ratio of allowance for loan losses to the end of period loans, net of unearned income and deferred fees |  | 1.33% | 1.33% | 1.34%
Ratio of net charge-offs to average loans, net of unearned income and deferred fees(1) | [1] | 0.26% | 0.14% | 0.32%
[1] | Net charge-offs are on an annualized basis.

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