XML 89 R76.htm IDEA: XBRL DOCUMENT
v3.22.4

Note 11 - Minimum Regulatory Capital Requirement (Details Textual) - USD ($) $ in Thousands | Dec. 31, 2022 | Dec. 31, 2021
--- | --- | ---
National Bank of Blacksburg [Member] |  |
Banking Regulation, Risk-Weighted Assets, Actual | $ 1,092,101 | $ 989,503

X
- Definition Amount of risk-weighted assets as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI https://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_RiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | dei_LegalEntityAxis=nksh_NationalBankOfBlacksburgMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |