Document And Entity Information - USD ($) |
12 Months Ended | ||||||||
|---|---|---|---|---|---|---|---|---|---|
Dec. 31, 2025 |
Mar. 27, 2026 |
Jun. 30, 2025 |
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| Document Information [Line Items] | |||||||||
| Entity Central Index Key | 0000796534 | ||||||||
| Entity Registrant Name | NATIONAL BANKSHARES, INC. | ||||||||
| Amendment Flag | false | ||||||||
| Current Fiscal Year End Date | --12-31 | ||||||||
| Document Fiscal Period Focus | FY | ||||||||
| Document Fiscal Year Focus | 2025 | ||||||||
| Document Type | 10-K | ||||||||
| Document Annual Report | true | ||||||||
| Document Period End Date | Dec. 31, 2025 | ||||||||
| Document Transition Report | false | ||||||||
| Entity File Number | 0-15204 | ||||||||
| Entity Incorporation, State or Country Code | VA | ||||||||
| Entity Tax Identification Number | 54-1375874 | ||||||||
| Entity Address, Address Line One | 101 Hubbard Street | ||||||||
| Entity Address, City or Town | Blacksburg | ||||||||
| Entity Address, State or Province | VA | ||||||||
| Entity Address, Postal Zip Code | 24062-9002 | ||||||||
| City Area Code | 540 | ||||||||
| Local Phone Number | 951-6300 | ||||||||
| Title of 12(b) Security | Common Stock, par value $1.25 per share | ||||||||
| Trading Symbol | NKSH | ||||||||
| Security Exchange Name | NASDAQ | ||||||||
| Entity Well-known Seasoned Issuer | No | ||||||||
| Entity Voluntary Filers | No | ||||||||
| Entity Current Reporting Status | Yes | ||||||||
| Entity Interactive Data Current | Yes | ||||||||
| Entity Filer Category | Non-accelerated Filer | ||||||||
| Entity Small Business | true | ||||||||
| Entity Emerging Growth Company | false | ||||||||
| ICFR Auditor Attestation Flag | false | ||||||||
| Document Financial Statement Error Correction [Flag] | false | ||||||||
| Entity Shell Company | false | ||||||||
| Entity Public Float | $ 173,155,227 | ||||||||
| Entity Common Stock, Shares Outstanding | 6,368,410 | ||||||||
| Auditor Name | Yount, Hyde & Barbour, P.C | ||||||||
| Auditor Firm ID | 613 | ||||||||
| Auditor Location | Winchester, Virginia | ||||||||
| Documents Incorporated by Reference [Text Block] | DOCUMENTS INCORPORATED BY REFERENCE Portions of the following document is incorporated herein by reference into the Part of the Form 10-K indicated.
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| Auditor Opinion [Text Block] | Opinion on the Financial Statements We have audited the accompanying consolidated balance sheets of National Bankshares, Inc. and its subsidiaries (the Company) as of December 31, 2025 and 2024, the related consolidated statements of income, comprehensive income, changes in stockholders' equity and cash flows for the years then ended, and the related notes to the consolidated financial statements (collectively, the financial statements). In our opinion, the financial statements present fairly, in all material respects, the financial position of the Company as of December 31, 2025 and 2024, and the results of its operations and its cash flows for the years then ended, in conformity with accounting principles generally accepted in the United States of America. |