<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.20.2</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>153</ContextCount>
  <ElementCount>285</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>46</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>5</UnitCount>
  <MyReports>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>1001 - Document - Cover Page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/CoverPage</Role>
      <ShortName>Cover Page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1002 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/ConsolidatedBalanceSheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1003 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/ConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1004 - Statement - Consolidated Statements of Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/ConsolidatedStatementsOfIncome</Role>
      <ShortName>Consolidated Statements of Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1005 - Statement - Consolidated Statements of Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/ConsolidatedStatementsOfComprehensiveIncome</Role>
      <ShortName>Consolidated Statements of Comprehensive Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1006 - Statement - Consolidated Statements of Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/ConsolidatedStatementsOfEquity</Role>
      <ShortName>Consolidated Statements of Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>1007 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/ConsolidatedStatementsOfCashFlows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>1008 - Disclosure - Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/AccountingPolicies</Role>
      <ShortName>Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>1009 - Disclosure - Cash and Marketable Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/CashAndMarketableSecurities</Role>
      <ShortName>Cash and Marketable Securities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>1010 - Disclosure - Inventories</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/Inventories</Role>
      <ShortName>Inventories</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>1011 - Disclosure - Leases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/Leases</Role>
      <ShortName>Leases</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>1012 - Disclosure - Revenue Recognition</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/RevenueRecognition</Role>
      <ShortName>Revenue Recognition</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>1013 - Disclosure - Net Income per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/NetIncomePerShare</Role>
      <ShortName>Net Income per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>1014 - Disclosure - Segment Information and Geographic Data</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/SegmentInformationAndGeographicData</Role>
      <ShortName>Segment Information and Geographic Data</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>1015 - Disclosure - Equity Compensation Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/EquityCompensationPlans</Role>
      <ShortName>Equity Compensation Plans</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>1016 - Disclosure - Business and Product Line Acquisitions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/BusinessAndProductLineAcquisitions</Role>
      <ShortName>Business and Product Line Acquisitions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>1017 - Disclosure - Long Term Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/LongTermDebt</Role>
      <ShortName>Long Term Debt</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>1018 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/CommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>1019 - Disclosure - Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/AccountingPoliciesPolicies</Role>
      <ShortName>Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://neogencorp.com/role/AccountingPolicies</ParentRole>
      <Position>19</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>1020 - Disclosure - Cash and Marketable Securities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/CashAndMarketableSecuritiesTables</Role>
      <ShortName>Cash and Marketable Securities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://neogencorp.com/role/CashAndMarketableSecurities</ParentRole>
      <Position>20</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>1021 - Disclosure - Inventories (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/InventoriesTables</Role>
      <ShortName>Inventories (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://neogencorp.com/role/Inventories</ParentRole>
      <Position>21</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>1022 - Disclosure - Leases (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/LeasesTables</Role>
      <ShortName>Leases (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://neogencorp.com/role/Leases</ParentRole>
      <Position>22</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>1023 - Disclosure - Revenue Recognition (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/RevenueRecognitionTables</Role>
      <ShortName>Revenue Recognition (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://neogencorp.com/role/RevenueRecognition</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>1024 - Disclosure - Net Income per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/NetIncomePerShareTables</Role>
      <ShortName>Net Income per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://neogencorp.com/role/NetIncomePerShare</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>1025 - Disclosure - Segment Information and Geographic Data (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/SegmentInformationAndGeographicDataTables</Role>
      <ShortName>Segment Information and Geographic Data (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://neogencorp.com/role/SegmentInformationAndGeographicData</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>1026 - Disclosure - Equity Compensation Plans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/EquityCompensationPlansTables</Role>
      <ShortName>Equity Compensation Plans (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://neogencorp.com/role/EquityCompensationPlans</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>1027 - Disclosure - Accounting Policies - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/AccountingPoliciesAdditionalInformationDetail</Role>
      <ShortName>Accounting Policies - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>1028 - Disclosure - Cash and Marketable Securities - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/CashAndMarketableSecuritiesAdditionalInformationDetail</Role>
      <ShortName>Cash and Marketable Securities - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>1029 - Disclosure - Marketable Securities (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/MarketableSecuritiesDetail</Role>
      <ShortName>Marketable Securities (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>1030 - Disclosure - Components of marketable securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/ComponentsOfMarketableSecuritiesDetails</Role>
      <ShortName>Components of marketable securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>1031 - Disclosure - Inventories (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/InventoriesDetail</Role>
      <ShortName>Inventories (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://neogencorp.com/role/InventoriesTables</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>1032 - Disclosure - Supplemental Balance Sheet Information Related to Operating Leases (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/SupplementalBalanceSheetInformationRelatedToOperatingLeasesDetail</Role>
      <ShortName>Supplemental Balance Sheet Information Related to Operating Leases (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>1033 - Disclosure - Weighted Average Remaining Lease Term and Weighted Average Discount Rate (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/WeightedAverageRemainingLeaseTermAndWeightedAverageDiscountRateDetail</Role>
      <ShortName>Weighted Average Remaining Lease Term and Weighted Average Discount Rate (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>1034 - Disclosure - Components of Lease Expense (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/ComponentsOfLeaseExpenseDetail</Role>
      <ShortName>Components of Lease Expense (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>1035 - Disclosure - Undiscounted Minimum Lease Payments (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/UndiscountedMinimumLeasePaymentsDetail</Role>
      <ShortName>Undiscounted Minimum Lease Payments (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>1036 - Disclosure - Revenue Recognition- Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/RevenueRecognitionAdditionalInformationDetail</Role>
      <ShortName>Revenue Recognition- Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>1037 - Disclosure - Disaggregated Revenue (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/DisaggregatedRevenueDetail</Role>
      <ShortName>Disaggregated Revenue (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>1038 - Disclosure - Calculation of Net Income Per Share (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/CalculationOfNetIncomePerShareDetail</Role>
      <ShortName>Calculation of Net Income Per Share (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>1039 - Disclosure - Segment Information and Geographic Data (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/SegmentInformationAndGeographicDataDetail</Role>
      <ShortName>Segment Information and Geographic Data (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://neogencorp.com/role/SegmentInformationAndGeographicDataTables</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>1040 - Disclosure - Segment Information and Geographic Data - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/SegmentInformationAndGeographicDataAdditionalInformationDetail</Role>
      <ShortName>Segment Information and Geographic Data - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>1041 - Disclosure - Disaggregated Revenue by Geographic Location (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/DisaggregatedRevenueByGeographicLocationDetail</Role>
      <ShortName>Disaggregated Revenue by Geographic Location (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>1042 - Disclosure - Stock Option Activity (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/StockOptionActivityDetail</Role>
      <ShortName>Stock Option Activity (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>1043 - Disclosure - Fair Value of Stock Options Granted, Estimated using Weighted-Average Assumptions (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/FairValueOfStockOptionsGrantedEstimatedUsingWeightedAverageAssumptionsDetail</Role>
      <ShortName>Fair Value of Stock Options Granted, Estimated using Weighted-Average Assumptions (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>1044 - Disclosure - Equity Compensation Plans - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/EquityCompensationPlansAdditionalInformationDetail</Role>
      <ShortName>Equity Compensation Plans - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>1045 - Disclosure - Business and Product Line Acquisitions - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/BusinessAndProductLineAcquisitionsAdditionalInformationDetail</Role>
      <ShortName>Business and Product Line Acquisitions - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>1046 - Disclosure - Long Term Debt - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/LongTermDebtAdditionalInformationDetail</Role>
      <ShortName>Long Term Debt - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="d21442d10q.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>1047 - Disclosure - Commitments and Contingencies - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://neogencorp.com/role/CommitmentsAndContingenciesAdditionalInformationDetail</Role>
      <ShortName>Commitments and Contingencies - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="10-Q" original="d21442d10q.htm">d21442d10q.htm</File>
    <File>d21442dex311.htm</File>
    <File>d21442dex312.htm</File>
    <File>d21442dex32.htm</File>
    <File>neog-20200831.xsd</File>
    <File>neog-20200831_cal.xml</File>
    <File>neog-20200831_def.xml</File>
    <File>neog-20200831_lab.xml</File>
    <File>neog-20200831_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/srt/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/us-gaap/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/country/2017-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
