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Note 11 - Minimum Regulatory Capital Requirement (Details Textual) - USD ($) $ in Thousands | Dec. 31, 2023 | Dec. 31, 2022
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National Bank of Blacksburg [Member] |  |
Banking Regulation, Risk-Weighted Assets, Actual | $ 1,082,158 | $ 1,092,101

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- Definition Amount of risk-weighted assets as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 505 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (c)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480696/942-505-50-1 + Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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- Details
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Data Type: | na
Balance Type: |
Period Type: |