<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.25.4</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>250</ContextCount>
  <ElementCount>436</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>72</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>4</UnitCount>
  <MyReports>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>000 - Document - Document And Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-document-and-entity-information</Role>
      <ShortName>Document And Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>001 - Statement - Consolidated Statements of Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-consolidated-statements-of-operations</Role>
      <ShortName>Consolidated Statements of Operations</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>002 - Statement - Consolidated Statements of Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-consolidated-statements-of-comprehensive-income</Role>
      <ShortName>Consolidated Statements of Comprehensive Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>003 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-consolidated-balance-sheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>004 - Statement - Consolidated Balance Sheets (Parentheticals)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-consolidated-balance-sheets-parentheticals</Role>
      <ShortName>Consolidated Balance Sheets (Parentheticals)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>005 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-consolidated-statements-of-cash-flows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>006 - Statement - Consolidated Statements of Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-consolidated-statements-of-equity</Role>
      <ShortName>Consolidated Statements of Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>007 - Statement - Consolidated Statements of Equity (Parentheticals)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-consolidated-statements-of-equity-parentheticals</Role>
      <ShortName>Consolidated Statements of Equity (Parentheticals)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>995443 - Disclosure - Award Timing Disclosure</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/AwardTimingDisclosure</Role>
      <ShortName>Award Timing Disclosure</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>995445 - Disclosure - Insider Trading Arrangements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements</Role>
      <ShortName>Insider Trading Arrangements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>995447 - Disclosure - Insider Trading Policies and Procedures</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/InsiderTradingPoliciesProc</Role>
      <ShortName>Insider Trading Policies and Procedures</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>995550 - Disclosure - Cybersecurity Risk Management and Strategy Disclosure</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/cyd/role/CybersecurityRiskManagementAndStrategyDisclosure</Role>
      <ShortName>Cybersecurity Risk Management and Strategy Disclosure</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>995551 - Disclosure - Note 1 - Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-1-summary-of-significant-accounting-policies</Role>
      <ShortName>Note 1 - Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>995552 - Disclosure - Note 2 - Net Patient Revenues</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-2-net-patient-revenues</Role>
      <ShortName>Note 2 - Net Patient Revenues</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>995553 - Disclosure - Note 3 - Other Revenues</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-3-other-revenues</Role>
      <ShortName>Note 3 - Other Revenues</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>995554 - Disclosure - Note 4 - Non-operating Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-4-nonoperating-income</Role>
      <ShortName>Note 4 - Non-operating Income</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>995555 - Disclosure - Note 5 - Business Segments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-5-business-segments-</Role>
      <ShortName>Note 5 - Business Segments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>995556 - Disclosure - Note 6 - Long-term Leases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-6-longterm-leases</Role>
      <ShortName>Note 6 - Long-term Leases</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>995557 - Disclosure - Note 7 - Earnings Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-7-earnings-per-share</Role>
      <ShortName>Note 7 - Earnings Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>995558 - Disclosure - Note 8 - Investments in Marketable Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-8-investments-in-marketable-securities</Role>
      <ShortName>Note 8 - Investments in Marketable Securities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>995559 - Disclosure - Note 9 - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-9-fair-value-measurements</Role>
      <ShortName>Note 9 - Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>995560 - Disclosure - Note 10 - Property and Equipment</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-10-property-and-equipment</Role>
      <ShortName>Note 10 - Property and Equipment</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>995561 - Disclosure - Note 11 - Goodwill and Other Intangible Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-11-goodwill-and-other-intangible-assets</Role>
      <ShortName>Note 11 - Goodwill and Other Intangible Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>995562 - Disclosure - Note 12 - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-12-income-taxes</Role>
      <ShortName>Note 12 - Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>995563 - Disclosure - Note 13 - Stock Repurchase Program</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-13-stock-repurchase-program</Role>
      <ShortName>Note 13 - Stock Repurchase Program</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>995564 - Disclosure - Note 14 - Stock-based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-14-stockbased-compensation</Role>
      <ShortName>Note 14 - Stock-based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>995565 - Disclosure - Note 15 - Long-term Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-15-longterm-debt</Role>
      <ShortName>Note 15 - Long-term Debt</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>995566 - Disclosure - Note 16 - Contingencies, Commitments and Other Matters</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-16-contingencies-commitments-and-other-matters</Role>
      <ShortName>Note 16 - Contingencies, Commitments and Other Matters</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>995567 - Disclosure - Note 17 - Relationship With National Health Corporation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-17-relationship-with-national-health-corporation</Role>
      <ShortName>Note 17 - Relationship With National Health Corporation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>995571 - Disclosure - Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-significant-accounting-policies-policies</Role>
      <ShortName>Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-1-summary-of-significant-accounting-policies</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>995572 - Disclosure - Note 2 - Net Patient Revenues (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-2-net-patient-revenues-tables</Role>
      <ShortName>Note 2 - Net Patient Revenues (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-2-net-patient-revenues</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>995573 - Disclosure - Note 3 - Other Revenues (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-3-other-revenues-tables</Role>
      <ShortName>Note 3 - Other Revenues (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-3-other-revenues</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>995574 - Disclosure - Note 4 - Non-operating Income (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-4-nonoperating-income-tables</Role>
      <ShortName>Note 4 - Non-operating Income (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-4-nonoperating-income</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>995575 - Disclosure - Note 5 - Business Segments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-5-business-segments-tables</Role>
      <ShortName>Note 5 - Business Segments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-5-business-segments-</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>995576 - Disclosure - Note 6 - Long-term Leases (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-6-longterm-leases-tables</Role>
      <ShortName>Note 6 - Long-term Leases (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-6-longterm-leases</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>995577 - Disclosure - Note 7 - Earnings Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-7-earnings-per-share-tables</Role>
      <ShortName>Note 7 - Earnings Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-7-earnings-per-share</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>995578 - Disclosure - Note 8 - Investments in Marketable Securities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-8-investments-in-marketable-securities-tables</Role>
      <ShortName>Note 8 - Investments in Marketable Securities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-8-investments-in-marketable-securities</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>995579 - Disclosure - Note 9 - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-9-fair-value-measurements-tables</Role>
      <ShortName>Note 9 - Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-9-fair-value-measurements</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>995580 - Disclosure - Note 10 - Property and Equipment (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-10-property-and-equipment-tables</Role>
      <ShortName>Note 10 - Property and Equipment (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-10-property-and-equipment</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>995581 - Disclosure - Note 11 - Goodwill and Other Intangible Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-11-goodwill-and-other-intangible-assets-tables</Role>
      <ShortName>Note 11 - Goodwill and Other Intangible Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-11-goodwill-and-other-intangible-assets</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>995582 - Disclosure - Note 12 - Income Taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-12-income-taxes-tables</Role>
      <ShortName>Note 12 - Income Taxes (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-12-income-taxes</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>995583 - Disclosure - Note 14 - Stock-based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-14-stockbased-compensation-tables</Role>
      <ShortName>Note 14 - Stock-based Compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-14-stockbased-compensation</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>995584 - Disclosure - Note 15 - Long-term Debt (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-15-longterm-debt-tables</Role>
      <ShortName>Note 15 - Long-term Debt (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-15-longterm-debt</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>995585 - Disclosure - Note 1 - Summary of Significant Accounting Policies (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-1-summary-of-significant-accounting-policies-details-textual</Role>
      <ShortName>Note 1 - Summary of Significant Accounting Policies (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>995586 - Disclosure - Note 2 - Net Patient Revenues (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-2-net-patient-revenues-details-textual</Role>
      <ShortName>Note 2 - Net Patient Revenues (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-2-net-patient-revenues-tables</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>995587 - Disclosure - Note 2 - Net Patient Revenues - Revenue Disaggregation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-2-net-patient-revenues-revenue-disaggregation-details</Role>
      <ShortName>Note 2 - Net Patient Revenues - Revenue Disaggregation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>995588 - Disclosure - Note 3 - Other Revenues (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-3-other-revenues-details-textual</Role>
      <ShortName>Note 3 - Other Revenues (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-3-other-revenues-tables</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>995589 - Disclosure - Note 3 - Other Revenues - Summary of Other Revenues (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-3-other-revenues-summary-of-other-revenues-details</Role>
      <ShortName>Note 3 - Other Revenues - Summary of Other Revenues (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>995590 - Disclosure - Note 3 - Other Revenues - Rental Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-3-other-revenues-rental-income-details</Role>
      <ShortName>Note 3 - Other Revenues - Rental Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>995591 - Disclosure - Note 3 - Other Revenues - Minimum Lease Payments Receivable (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-3-other-revenues-minimum-lease-payments-receivable-details</Role>
      <ShortName>Note 3 - Other Revenues - Minimum Lease Payments Receivable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>995592 - Disclosure - Note 4 - Non-operating Income (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-4-nonoperating-income-details-textual</Role>
      <ShortName>Note 4 - Non-operating Income (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-4-nonoperating-income-tables</ParentRole>
      <Position>51</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>995593 - Disclosure - Note 4 - Non-operating Income - Summary of Non-operating Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-4-nonoperating-income-summary-of-nonoperating-income-details</Role>
      <ShortName>Note 4 - Non-operating Income - Summary of Non-operating Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>995594 - Disclosure - Note 5 - Business Segments (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-5-business-segments-details-textual</Role>
      <ShortName>Note 5 - Business Segments (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-5-business-segments-tables</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>995595 - Disclosure - Note 5 - Business Segments - Summary of Financial Information by Reporting Segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-5-business-segments-summary-of-financial-information-by-reporting-segment-details</Role>
      <ShortName>Note 5 - Business Segments - Summary of Financial Information by Reporting Segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>995596 - Disclosure - Note 6 - Long-term Leases (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-6-longterm-leases-details-textual</Role>
      <ShortName>Note 6 - Long-term Leases (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-6-longterm-leases-tables</ParentRole>
      <Position>55</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>995597 - Disclosure - Note 6 - Long-term Leases - Maturity of Lease Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-6-longterm-leases-maturity-of-lease-liabilities-details</Role>
      <ShortName>Note 6 - Long-term Leases - Maturity of Lease Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>995598 - Disclosure - Note 6 - Long-term Leases - Lease Information and Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-6-longterm-leases-lease-information-and-expense-details</Role>
      <ShortName>Note 6 - Long-term Leases - Lease Information and Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>995599 - Disclosure - Note 7 - Earnings Per Share (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-7-earnings-per-share-details-textual</Role>
      <ShortName>Note 7 - Earnings Per Share (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-7-earnings-per-share-tables</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>995600 - Disclosure - Note 7 - Earnings Per Share - Summary of Earnings and Weighted Average Number of Common Shares Used in Calculation of Basic and Diluted Earnings Per Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-7-earnings-per-share-summary-of-earnings-and-weighted-average-number-of-common-shares-used-in-calculation-of-basic-and-diluted-earnings-per-share-details</Role>
      <ShortName>Note 7 - Earnings Per Share - Summary of Earnings and Weighted Average Number of Common Shares Used in Calculation of Basic and Diluted Earnings Per Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>995601 - Disclosure - Note 8 - Investments in Marketable Securities (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-8-investments-in-marketable-securities-details-textual</Role>
      <ShortName>Note 8 - Investments in Marketable Securities (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-8-investments-in-marketable-securities-tables</ParentRole>
      <Position>60</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>995602 - Disclosure - Note 8 - Investments in Marketable Securities - Marketable Securities and Restricted Marketable Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-8-investments-in-marketable-securities-marketable-securities-and-restricted-marketable-securities-details</Role>
      <ShortName>Note 8 - Investments in Marketable Securities - Marketable Securities and Restricted Marketable Securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>995603 - Disclosure - Note 8 - Investments in Marketable Securities - Available for Sale Marketable Equity Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-8-investments-in-marketable-securities-available-for-sale-marketable-equity-securities-details</Role>
      <ShortName>Note 8 - Investments in Marketable Securities - Available for Sale Marketable Equity Securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>995604 - Disclosure - Note 8 - Investments in Marketable Securities - Amortized Cost and Estimated Fair Value of Debt Securities as Available for Sale (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-8-investments-in-marketable-securities-amortized-cost-and-estimated-fair-value-of-debt-securities-as-available-for-sale-details</Role>
      <ShortName>Note 8 - Investments in Marketable Securities - Amortized Cost and Estimated Fair Value of Debt Securities as Available for Sale (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>995605 - Disclosure - Note 9 - Fair Value Measurements - Summary of Fair Value Measurements by Level (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-9-fair-value-measurements-summary-of-fair-value-measurements-by-level-details</Role>
      <ShortName>Note 9 - Fair Value Measurements - Summary of Fair Value Measurements by Level (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>995606 - Disclosure - Note 10 - Property and Equipment - Property and Equipment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-10-property-and-equipment-property-and-equipment-details</Role>
      <ShortName>Note 10 - Property and Equipment - Property and Equipment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>995607 - Disclosure - Note 11 - Goodwill and Other Intangible Assets (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-11-goodwill-and-other-intangible-assets-details-textual</Role>
      <ShortName>Note 11 - Goodwill and Other Intangible Assets (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-11-goodwill-and-other-intangible-assets-tables</ParentRole>
      <Position>66</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>995608 - Disclosure - Note 11 - Goodwill and Other Intangible Assets - Activity Related to Goodwill By Segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-11-goodwill-and-other-intangible-assets-activity-related-to-goodwill-by-segment-details</Role>
      <ShortName>Note 11 - Goodwill and Other Intangible Assets - Activity Related to Goodwill By Segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>995609 - Disclosure - Note 11 - Goodwill and Other Intangible Assets - Indefinite-lived Intangible Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-11-goodwill-and-other-intangible-assets-indefinitelived-intangible-assets-details</Role>
      <ShortName>Note 11 - Goodwill and Other Intangible Assets - Indefinite-lived Intangible Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>68</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>995610 - Disclosure - Note 12 - Income Taxes (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-12-income-taxes-details-textual</Role>
      <ShortName>Note 12 - Income Taxes (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-12-income-taxes-tables</ParentRole>
      <Position>69</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>995611 - Disclosure - Note 12 - Income Taxes - Income before Taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-12-income-taxes-income-before-taxes-details</Role>
      <ShortName>Note 12 - Income Taxes - Income before Taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>70</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>995612 - Disclosure - Note 12 - Income Taxes - Provision for Income Taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-12-income-taxes-provision-for-income-taxes-details</Role>
      <ShortName>Note 12 - Income Taxes - Provision for Income Taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>71</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>995613 - Disclosure - Note 12 - Income Taxes - Deferred Tax Assets and Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-12-income-taxes-deferred-tax-assets-and-liabilities-details</Role>
      <ShortName>Note 12 - Income Taxes - Deferred Tax Assets and Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>995614 - Disclosure - Note 12 - Income Taxes - Reconciliation of Income Tax Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-12-income-taxes-reconciliation-of-income-tax-expense-details</Role>
      <ShortName>Note 12 - Income Taxes - Reconciliation of Income Tax Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>73</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>995615 - Disclosure - Note 12 - Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-12-income-taxes-reconciliation-of-unrecognized-tax-benefits-details</Role>
      <ShortName>Note 12 - Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>74</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>995616 - Disclosure - Note 12 - Income Taxes - Cash Taxes Paid (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-12-income-taxes-cash-taxes-paid-details</Role>
      <ShortName>Note 12 - Income Taxes - Cash Taxes Paid (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>75</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>995617 - Disclosure - Note 13 - Stock Repurchase Program (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-13-stock-repurchase-program-details-textual</Role>
      <ShortName>Note 13 - Stock Repurchase Program (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-13-stock-repurchase-program</ParentRole>
      <Position>76</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>995618 - Disclosure - Note 14 - Stock-based Compensation (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-14-stockbased-compensation-details-textual</Role>
      <ShortName>Note 14 - Stock-based Compensation (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-14-stockbased-compensation-tables</ParentRole>
      <Position>77</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>995619 - Disclosure - Note 14 - Stock-based Compensation - Summary of Assumptions Used to Value Options Granted (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-14-stockbased-compensation-summary-of-assumptions-used-to-value-options-granted-details</Role>
      <ShortName>Note 14 - Stock-based Compensation - Summary of Assumptions Used to Value Options Granted (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>78</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>995620 - Disclosure - Note 14 - Stock-based Compensation - Summary of Options Outstanding (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-14-stockbased-compensation-summary-of-options-outstanding-details</Role>
      <ShortName>Note 14 - Stock-based Compensation - Summary of Options Outstanding (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>79</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>995621 - Disclosure - Note 14 - Stock-based Compensation - Options Outstanding by Exercise Price Range (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-14-stockbased-compensation-options-outstanding-by-exercise-price-range-details</Role>
      <ShortName>Note 14 - Stock-based Compensation - Options Outstanding by Exercise Price Range (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>80</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>995622 - Disclosure - Note 15 - Long-term Debt (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-15-longterm-debt-details-textual</Role>
      <ShortName>Note 15 - Long-term Debt (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-15-longterm-debt-tables</ParentRole>
      <Position>81</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>995623 - Disclosure - Note 15 - Long-term Debt - Summary of Long-term Debt (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-15-longterm-debt-summary-of-longterm-debt-details</Role>
      <ShortName>Note 15 - Long-term Debt - Summary of Long-term Debt (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>82</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>995624 - Disclosure - Note 15 - Long-term Debt - Maturities of Long-term Debt (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-15-longterm-debt-maturities-of-longterm-debt-details</Role>
      <ShortName>Note 15 - Long-term Debt - Maturities of Long-term Debt (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>83</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>995625 - Disclosure - Note 16 - Contingencies, Commitments and Other Matters (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-16-contingencies-commitments-and-other-matters-details-textual</Role>
      <ShortName>Note 16 - Contingencies, Commitments and Other Matters (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-16-contingencies-commitments-and-other-matters</ParentRole>
      <Position>84</Position>
    </Report>
    <Report instance="nhc20251231_10k.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>995626 - Disclosure - Note 17 - Relationship With National Health Corporation (Details Textual)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.nhccare.com/20251231/role/statement-note-17-relationship-with-national-health-corporation-details-textual</Role>
      <ShortName>Note 17 - Relationship With National Health Corporation (Details Textual)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.nhccare.com/20251231/role/statement-note-17-relationship-with-national-health-corporation</ParentRole>
      <Position>85</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>nhc-20251231.xsd</File>
    <File>nhc-20251231_cal.xml</File>
    <File>nhc-20251231_def.xml</File>
    <File>nhc-20251231_lab.xml</File>
    <File>nhc-20251231_pre.xml</File>
    <File doctype="10-K" isDefinitelyFs="true" isUsgaap="true" original="nhc20251231_10k.htm">nhc20251231_10k.htm</File>
  </InputFiles>
  <SupplementalFiles>
    <File>graph.jpg</File>
    <File>nhc01.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy items="1207">http://fasb.org/us-gaap/2025</BaseTaxonomy>
    <BaseTaxonomy items="10">http://xbrl.sec.gov/cyd/2025</BaseTaxonomy>
    <BaseTaxonomy items="37">http://xbrl.sec.gov/dei/2025</BaseTaxonomy>
    <BaseTaxonomy items="7">http://xbrl.sec.gov/ecd/2025</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
