<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.26.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>334</ContextCount>
  <ElementCount>395</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>102</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>10</UnitCount>
  <MyReports>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>75000 - Document - Cover Page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/CoverPage</Role>
      <ShortName>Cover Page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>75010 - Statement - Condensed Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/CondensedConsolidatedBalanceSheets</Role>
      <ShortName>Condensed Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>75020 - Statement - Condensed Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/CondensedConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Condensed Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>75030 - Statement - Condensed Consolidated Statements of Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/CondensedConsolidatedStatementsofOperations</Role>
      <ShortName>Condensed Consolidated Statements of Operations</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>75040 - Statement - Condensed Consolidated Statements of Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/CondensedConsolidatedStatementsofComprehensiveIncome</Role>
      <ShortName>Condensed Consolidated Statements of Comprehensive Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>75050 - Statement - Condensed Consolidated Statements of Changes in Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/CondensedConsolidatedStatementsofChangesinStockholdersEquity</Role>
      <ShortName>Condensed Consolidated Statements of Changes in Stockholders' Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>75060 - Statement - Condensed Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/CondensedConsolidatedStatementsofCashFlows</Role>
      <ShortName>Condensed Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>995410 - Disclosure - Pay vs Performance Disclosure</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://xbrl.sec.gov/ecd/role/PvpDisclosure</Role>
      <ShortName>Pay vs Performance Disclosure</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.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>9</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>995455 - Disclosure - Basis of Presentation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/BasisofPresentation</Role>
      <ShortName>Basis of Presentation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>995465 - Disclosure - Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/SummaryofSignificantAccountingPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>995475 - Disclosure - Revenue from Contracts with Customers</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/RevenuefromContractswithCustomers</Role>
      <ShortName>Revenue from Contracts with Customers</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>995485 - Disclosure - Fair Value of Financial Instruments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/FairValueofFinancialInstruments</Role>
      <ShortName>Fair Value of Financial Instruments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>995495 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/IncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>995505 - Disclosure - Inventory, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureInventoryNet</Role>
      <ShortName>Inventory, Net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>995515 - Disclosure - Property, Plant and Equipment, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/PropertyPlantandEquipmentNet</Role>
      <ShortName>Property, Plant and Equipment, Net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>995525 - Disclosure - SPECT Business</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureSpectBusiness</Role>
      <ShortName>SPECT Business</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>995535 - Disclosure - Accrued Expenses, and Other Current and Long-Term Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureAccruedExpensesAndOtherCurrentAndLongtermLiabilities</Role>
      <ShortName>Accrued Expenses, and Other Current and Long-Term Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>995555 - Disclosure - Goodwill and Intangibles, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureGoodwillAndIntangiblesNet1</Role>
      <ShortName>Goodwill and Intangibles, Net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>995565 - Disclosure - Long-Term Debt, and Other Borrowings, Net of Current Portion</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureLongtermDebtAndOtherBorrowingsNetOfCurrentPortion</Role>
      <ShortName>Long-Term Debt, and Other Borrowings, Net of Current Portion</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>995595 - Disclosure - Stockholders' Equity and Stock-Based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureStockholdersEquityAndStockbasedCompensation</Role>
      <ShortName>Stockholders' Equity and Stock-Based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>995605 - Disclosure - Net Income Per Common Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/NetIncomePerCommonShare</Role>
      <ShortName>Net Income Per Common Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>995615 - Disclosure - Other Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/OtherIncome</Role>
      <ShortName>Other Income</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>995625 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/CommitmentsandContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>995635 - Disclosure - Benefit Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/BenefitPlans</Role>
      <ShortName>Benefit Plans</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>995645 - Disclosure - Acquisitions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/Acquisitions</Role>
      <ShortName>Acquisitions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>995655 - Disclosure - Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/SegmentInformation</Role>
      <ShortName>Segment Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>995665 - Disclosure - Subsequent Event</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureSubsequentEvent1</Role>
      <ShortName>Subsequent Event</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>995675 - Disclosure - Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/SummaryofSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/SummaryofSignificantAccountingPolicies</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>995685 - Disclosure - Revenue from Contracts with Customers (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/RevenuefromContractswithCustomersTables</Role>
      <ShortName>Revenue from Contracts with Customers (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/RevenuefromContractswithCustomers</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>995695 - Disclosure - Fair Value of Financial Instruments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/FairValueofFinancialInstrumentsTables</Role>
      <ShortName>Fair Value of Financial Instruments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/FairValueofFinancialInstruments</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>995705 - Disclosure - Income Taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/IncomeTaxesTables</Role>
      <ShortName>Income Taxes (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/IncomeTaxes</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>995715 - Disclosure - Inventory, Net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureInventoryNetTables</Role>
      <ShortName>Inventory, Net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/DisclosureInventoryNet</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>995725 - Disclosure - Property, Plant and Equipment, Net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/PropertyPlantandEquipmentNetTables</Role>
      <ShortName>Property, Plant and Equipment, Net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/PropertyPlantandEquipmentNet</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>995735 - Disclosure - SPECT Business (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureSpectBusinessTables</Role>
      <ShortName>SPECT Business (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/DisclosureSpectBusiness</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>995745 - Disclosure - Accrued Expenses, and Other Current and Long-Term Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureAccruedExpensesAndOtherCurrentAndLongtermLiabilitiesTables</Role>
      <ShortName>Accrued Expenses, and Other Current and Long-Term Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/DisclosureAccruedExpensesAndOtherCurrentAndLongtermLiabilities</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>995765 - Disclosure - Goodwill and Intangibles, Net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureGoodwillAndIntangiblesNetTables</Role>
      <ShortName>Goodwill and Intangibles, Net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/DisclosureGoodwillAndIntangiblesNet1</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>995775 - Disclosure - Long-Term Debt, and Other Borrowings, Net of Current Portion (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureLongtermDebtAndOtherBorrowingsNetOfCurrentPortionTables</Role>
      <ShortName>Long-Term Debt, and Other Borrowings, Net of Current Portion (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/DisclosureLongtermDebtAndOtherBorrowingsNetOfCurrentPortion</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>995795 - Disclosure - Stockholders' Equity and Stock-Based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureStockholdersEquityAndStockbasedCompensationTables</Role>
      <ShortName>Stockholders' Equity and Stock-Based Compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/DisclosureStockholdersEquityAndStockbasedCompensation</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>995805 - Disclosure - Net Income Per Common Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/NetIncomePerCommonShareTables</Role>
      <ShortName>Net Income Per Common Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/NetIncomePerCommonShare</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>995815 - Disclosure - Other Income (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/OtherIncomeTables</Role>
      <ShortName>Other Income (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/OtherIncome</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>995825 - Disclosure - Acquisitions (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureAcquisitionsTables</Role>
      <ShortName>Acquisitions (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/Acquisitions</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>995835 - Disclosure - Segment Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/SegmentInformationTables</Role>
      <ShortName>Segment Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/SegmentInformation</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>995845 - Disclosure - Summary of Significant Accounting Policies - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesNarrativeDetails</Role>
      <ShortName>Summary of Significant Accounting Policies - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>995855 - Disclosure - Revenue from Contracts with Customers - Schedule of Disaggregation of Revenue (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/RevenuefromContractswithCustomersScheduleofDisaggregationofRevenueDetails</Role>
      <ShortName>Revenue from Contracts with Customers - Schedule of Disaggregation of Revenue (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>995865 - Disclosure - Revenue from Contracts with Customers - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/RevenuefromContractswithCustomersNarrativeDetails</Role>
      <ShortName>Revenue from Contracts with Customers - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>995875 - Disclosure - Revenue from Contracts with Customers - Schedule of Revenue by Geographic Region Determined by Location of Customer or Other Party (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureRevenueFromContractsWithCustomersScheduleOfRevenueByGeographicRegionDeterminedByLocationOfCustomerOrOtherPartyDetails</Role>
      <ShortName>Revenue from Contracts with Customers - Schedule of Revenue by Geographic Region Determined by Location of Customer or Other Party (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>995885 - Disclosure - Revenue from Contracts with Customers - Schedule of Amount of and Change in Accruals for Rebate Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureRevenueFromContractsWithCustomersScheduleOfAmountOfAndChangeInAccrualsForRebateLiabilitiesDetails</Role>
      <ShortName>Revenue from Contracts with Customers - Schedule of Amount of and Change in Accruals for Rebate Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>995895 - Disclosure - Revenue from Contracts with Customers - Schedule of Deferred Revenue (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureRevenueFromContractsWithCustomersScheduleOfDeferredRevenueDetails</Role>
      <ShortName>Revenue from Contracts with Customers - Schedule of Deferred Revenue (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>995905 - Disclosure - Fair Value of Financial Instruments - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/FairValueofFinancialInstrumentsScheduleofAssetsandLiabilitiesMeasuredatFairValueonaRecurringBasisDetails</Role>
      <ShortName>Fair Value of Financial Instruments - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>995915 - Disclosure - Fair Value of Financial Instruments - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureFairValueOfFinancialInstrumentsNarrativeDetails</Role>
      <ShortName>Fair Value of Financial Instruments - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>995925 - Disclosure - Fair Value of Financial Instruments - Schedule of Contingent Consideration Measured at Fair Value (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureFairValueOfFinancialInstrumentsScheduleOfContingentConsiderationMeasuredAtFairValueDetails</Role>
      <ShortName>Fair Value of Financial Instruments - Schedule of Contingent Consideration Measured at Fair Value (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>995935 - Disclosure - Fair Value of Financial Instruments - Schedule of Contingent Consideration Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureFairValueOfFinancialInstrumentsScheduleOfContingentConsiderationLiabilitiesDetails</Role>
      <ShortName>Fair Value of Financial Instruments - Schedule of Contingent Consideration Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>995945 - Disclosure - Fair Value of Financial Instruments - Schedule of Fair Value of Total Net Consideration Received Regarding Sale of Business (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureFairValueOfFinancialInstrumentsScheduleOfFairValueOfTotalNetConsiderationReceivedRegardingSaleOfBusinessDetails</Role>
      <ShortName>Fair Value of Financial Instruments - Schedule of Fair Value of Total Net Consideration Received Regarding Sale of Business (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>995955 - Disclosure - Fair Value of Financial Instruments - Schedule of Fair Value of Total Net Consideration Received Regarding Sale of Business (Parenthetical) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureFairValueOfFinancialInstrumentsScheduleOfFairValueOfTotalNetConsiderationReceivedRegardingSaleOfBusinessParentheticalDetails</Role>
      <ShortName>Fair Value of Financial Instruments - Schedule of Fair Value of Total Net Consideration Received Regarding Sale of Business (Parenthetical) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>995965 - Disclosure - Income Taxes - Schedule of Income Tax Expense and Effective Tax Rate (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureIncomeTaxesScheduleOfIncomeTaxExpenseAndEffectiveTaxRateDetails</Role>
      <ShortName>Income Taxes - Schedule of Income Tax Expense and Effective Tax Rate (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>995975 - Disclosure - Income Taxes - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureIncomeTaxesNarrativeDetails</Role>
      <ShortName>Income Taxes - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>995985 - Disclosure - Inventory, Net - Schedule of Inventory Net of Related Reserves (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureInventoryNetScheduleOfInventoryNetOfRelatedReservesDetails</Role>
      <ShortName>Inventory, Net - Schedule of Inventory Net of Related Reserves (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>995995 - Disclosure - Property, Plant and Equipment, Net - Schedule of Property, Plant, and Equipment, Net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/PropertyPlantandEquipmentNetScheduleofPropertyPlantandEquipmentNetDetails</Role>
      <ShortName>Property, Plant and Equipment, Net - Schedule of Property, Plant, and Equipment, Net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>996005 - Disclosure - Property, Plant and Equipment, Net - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosurePropertyPlantAndEquipmentNetNarrativeDetails</Role>
      <ShortName>Property, Plant and Equipment, Net - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>996015 - Disclosure - SPECT Business - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureSpectBusinessNarrativeDetails</Role>
      <ShortName>SPECT Business - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>996025 - Disclosure - SPECT Business - Schedule of Carrying Amounts of Assets and Liabilities Held for Sale (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureSpectBusinessScheduleOfCarryingAmountsOfAssetsAndLiabilitiesHeldForSaleDetails</Role>
      <ShortName>SPECT Business - Schedule of Carrying Amounts of Assets and Liabilities Held for Sale (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>996035 - Disclosure - Accrued Expenses, and Other Current and Long-Term Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureAccruedExpensesAndOtherCurrentAndLongtermLiabilitiesDetails</Role>
      <ShortName>Accrued Expenses, and Other Current and Long-Term Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/DisclosureAccruedExpensesAndOtherCurrentAndLongtermLiabilitiesTables</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>996045 - Disclosure - Goodwill and Intangibles, Net - Schedule of Change in Carrying Value of Goodwill (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureGoodwillAndIntangiblesNetScheduleOfChangeInCarryingValueOfGoodwillDetails</Role>
      <ShortName>Goodwill and Intangibles, Net - Schedule of Change in Carrying Value of Goodwill (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>996055 - Disclosure - Goodwill and Intangibles, Net - Schedule of Intangible Assets, Net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureGoodwillAndIntangiblesNetScheduleOfIntangibleAssetsNetDetails</Role>
      <ShortName>Goodwill and Intangibles, Net - Schedule of Intangible Assets, Net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>996075 - Disclosure - Goodwill and Intangibles, Net - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureGoodwillAndIntangiblesNetNarrativeDetails</Role>
      <ShortName>Goodwill and Intangibles, Net - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>996085 - Disclosure - Goodwill and Intangibles, Net - Schedule of Estimated Aggregate Amortization Expense Related to Intangible Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureGoodwillAndIntangiblesNetScheduleOfEstimatedAggregateAmortizationExpenseRelatedToIntangibleAssetsDetails</Role>
      <ShortName>Goodwill and Intangibles, Net - Schedule of Estimated Aggregate Amortization Expense Related to Intangible Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>996095 - Disclosure - Long-Term Debt, and Other Borrowings, Net of Current Portion - Schedule of Maturities of Principal Obligations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureLongtermDebtAndOtherBorrowingsNetOfCurrentPortionScheduleOfMaturitiesOfPrincipalObligationsDetails</Role>
      <ShortName>Long-Term Debt, and Other Borrowings, Net of Current Portion - Schedule of Maturities of Principal Obligations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>68</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>996115 - Disclosure - Long-Term Debt, and Other Borrowings, Net of Current Portion - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureLongtermDebtAndOtherBorrowingsNetOfCurrentPortionNarrativeDetails</Role>
      <ShortName>Long-Term Debt, and Other Borrowings, Net of Current Portion - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/DisclosureLongtermDebtAndOtherBorrowingsNetOfCurrentPortionTables</ParentRole>
      <Position>69</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>996125 - Disclosure - Stockholders' Equity and Stock-Based Compensation - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureStockholdersEquityAndStockbasedCompensationNarrativeDetails</Role>
      <ShortName>Stockholders' Equity and Stock-Based Compensation - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/DisclosureStockholdersEquityAndStockbasedCompensationTables</ParentRole>
      <Position>70</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>996135 - Disclosure - Stockholders' Equity and Stock-Based Compensation - Stock-Based Compensation Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureStockholdersEquityAndStockbasedCompensationStockbasedCompensationExpenseDetails</Role>
      <ShortName>Stockholders' Equity and Stock-Based Compensation - Stock-Based Compensation Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>71</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>996145 - Disclosure - Net Income Per Common Share - Schedule of Net Income Per Common Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/NetIncomePerCommonShareScheduleofNetIncomePerCommonShareDetails</Role>
      <ShortName>Net Income Per Common Share - Schedule of Net Income Per Common Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>996155 - Disclosure - Other Income - Summary of Other Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureOtherIncomeSummaryOfOtherIncomeDetails</Role>
      <ShortName>Other Income - Summary of Other Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>73</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>996165 - Disclosure - Other Income - Summary of Other Income - (Parenthetical) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureOtherIncomeSummaryOfOtherIncomeParentheticalDetails</Role>
      <ShortName>Other Income - Summary of Other Income - (Parenthetical) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>74</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>996175 - Disclosure - Commitments and Contingencies - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureCommitmentsAndContingenciesNarrativeDetails</Role>
      <ShortName>Commitments and Contingencies - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>75</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>996185 - Disclosure - Benefit Plans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/BenefitPlansDetails</Role>
      <ShortName>Benefit Plans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/BenefitPlans</ParentRole>
      <Position>76</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>996195 - Disclosure - Acquisitions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/AcquisitionsDetails</Role>
      <ShortName>Acquisitions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.lantheus.com/20260630/taxonomy/role/DisclosureAcquisitionsTables</ParentRole>
      <Position>77</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>996205 - Disclosure - Acquisitions - Summary of Acquisition Date Fair Value of Provisional Consideration Transferred in Acquisition (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureAcquisitionsSummaryOfAcquisitionDateFairValueOfProvisionalConsiderationTransferredInAcquisitionDetails</Role>
      <ShortName>Acquisitions - Summary of Acquisition Date Fair Value of Provisional Consideration Transferred in Acquisition (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>78</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>996215 - Disclosure - Acquisitions - Summary of Fair Value of Assets Acquired and Liabilities Assumed (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureAcquisitionsSummaryOfFairValueOfAssetsAcquiredAndLiabilitiesAssumedDetails</Role>
      <ShortName>Acquisitions - Summary of Fair Value of Assets Acquired and Liabilities Assumed (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>79</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>996225 - Disclosure - Acquisitions - Summary of Fair Value of Assets Acquired and Liabilities Assumed (Parenthetical) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureAcquisitionsSummaryOfFairValueOfAssetsAcquiredAndLiabilitiesAssumedParentheticalDetails</Role>
      <ShortName>Acquisitions - Summary of Fair Value of Assets Acquired and Liabilities Assumed (Parenthetical) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>80</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>996235 - Disclosure - Segment Information - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureSegmentInformationNarrativeDetails</Role>
      <ShortName>Segment Information - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>81</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>996245 - Disclosure - Segment Information - Schedule of Research and Development Expenses (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureSegmentInformationScheduleOfResearchAndDevelopmentExpensesDetails</Role>
      <ShortName>Segment Information - Schedule of Research and Development Expenses (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>82</Position>
    </Report>
    <Report instance="lnth-20260630.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>996255 - Disclosure - Subsequent Event - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.lantheus.com/20260630/taxonomy/role/DisclosureSubsequentEventNarrativeDetails</Role>
      <ShortName>Subsequent Event - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>83</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" isDefinitelyFs="true" isUsgaap="true" original="lnth-20260630.htm">lnth-20260630.htm</File>
    <File>lnth-20260630.xsd</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy items="1">http://fasb.org/srt/2026</BaseTaxonomy>
    <BaseTaxonomy items="973">http://fasb.org/us-gaap/2026</BaseTaxonomy>
    <BaseTaxonomy items="29">http://xbrl.sec.gov/dei/2026</BaseTaxonomy>
    <BaseTaxonomy items="4">http://xbrl.sec.gov/ecd/2026</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>false</HasPresentationLinkbase>
  <HasCalculationLinkbase>false</HasCalculationLinkbase>
</FilingSummary>
