XML 70 R59.htm IDEA: XBRL DOCUMENT
v3.26.1

Note 3 - Securities - Realized Gains and Losses From Calls of Securities (Details) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2024 USD ($)
Investments, Debt and Equity Securities [Abstract] |
Sale of Available for Sale Securities, proceeds | $ 9,279
Sale of Available for Sale Securities, book value | 9,279
Sale of Available for Sale Securities, gross gain | 0
Sale of Available for Sale Securities, gross loss | 0
Sale of Available for Sale Securities, net gain (loss) | $ 0

X
- Definition Book value of available-for-sale securities that were called during the period. + References No definition available. + Details
Name: | nksh_AvailableforsaleSecuritiesCalled
Namespace Prefix: | nksh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The gross realized gain on available-for-sale securities that were called during the period. + References No definition available. + Details
Name: | nksh_AvailableforsaleSecuritiesGrossRealizedGainCalled
Namespace Prefix: | nksh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The gross realized gain (loss) on available-for-sale securities that were called during the period. + References No definition available. + Details
Name: | nksh_AvailableforsaleSecuritiesGrossRealizedGainLossCalled
Namespace Prefix: | nksh_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The gross realized loss on available-for-sale securities that were called during the period. + References No definition available. + Details
Name: | nksh_AvailableforsaleSecuritiesGrossRealizedLossCalled
Namespace Prefix: | nksh_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash inflow associated with calls (requests of early payments) on securities not classified as either held-to-maturity securities or trading securities which are classified as available-for-sale securities. + References No definition available. + Details
Name: | nksh_ProceedsFromCallsOfAvailableforsaleSecurities
Namespace Prefix: | nksh_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration