XML 42 R32.htm IDEA: XBRL DOCUMENT
v3.22.2.2

Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Ratios of Allowance for Loan Losses (Details) | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 2022 | Sep. 30, 2021 | Dec. 31, 2021
Ratio of allowance for loan losses to the end of period loans, net of unearned income and deferred fees and costs(1) |  | 0.96% | 0.97% | 0.96%
Ratio of net charge-offs to average loans, net of unearned income and deferred fees and costs(1) | [1] | 0.03% | 0.08% | 0.05%
[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: | dtr-types: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: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration