<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.20.4</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>482</ContextCount>
  <ElementCount>631</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>131</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>14</UnitCount>
  <MyReports>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>100000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>100010 - Statement - Consolidated Statements of Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/StatementConsolidatedStatementsOfIncome</Role>
      <ShortName>Consolidated Statements of Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>100020 - Statement - Consolidated Statements of Comprehensive Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/StatementConsolidatedStatementsOfComprehensiveIncome</Role>
      <ShortName>Consolidated Statements of Comprehensive Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>100030 - Statement - Consolidated Statements of Comprehensive Income (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/StatementConsolidatedStatementsOfComprehensiveIncomeParenthetical</Role>
      <ShortName>Consolidated Statements of Comprehensive Income (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>100040 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/StatementConsolidatedBalanceSheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>100050 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/StatementConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>100060 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/StatementConsolidatedStatementsOfCashFlows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>100070 - Statement - Consolidated Statements of Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/StatementConsolidatedStatementsOfEquity</Role>
      <ShortName>Consolidated Statements of Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>100080 - Statement - Consolidated Statements of Equity (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/StatementConsolidatedStatementsOfEquityParenthetical</Role>
      <ShortName>Consolidated Statements of Equity (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>100090 - Disclosure - Summary of Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureSummaryOfSignificantAccountingPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>100100 - Disclosure - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureFairValueMeasurements</Role>
      <ShortName>Fair Value Measurements</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>100110 - Disclosure - Derivative Instruments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureDerivativeInstruments</Role>
      <ShortName>Derivative Instruments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>100120 - Disclosure - Goodwill and Other Intangible Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureGoodwillAndOtherIntangibleAssets</Role>
      <ShortName>Goodwill and Other Intangible Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>100130 - Disclosure - Inventories</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureInventories</Role>
      <ShortName>Inventories</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>100140 - Disclosure - Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureDebt</Role>
      <ShortName>Debt</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>100150 - Disclosure - Leases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureLeases</Role>
      <ShortName>Leases</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>100160 - Disclosure - Other, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureOtherNet</Role>
      <ShortName>Other, Net</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>100170 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureIncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>100180 - Disclosure - Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureStockholdersEquity</Role>
      <ShortName>Stockholders' Equity</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>100190 - Disclosure - Stock-based Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureStockBasedCompensation</Role>
      <ShortName>Stock-based Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>100200 - Disclosure - Deferred Compensation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureDeferredCompensation</Role>
      <ShortName>Deferred Compensation</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>100210 - Disclosure - Postretirement Benefit Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosurePostretirementBenefitPlans</Role>
      <ShortName>Postretirement Benefit Plans</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>100220 - Disclosure - Accrued Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureAccruedLiabilities</Role>
      <ShortName>Accrued Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>100230 - Disclosure - Other Non-Current Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureOtherNonCurrentLiabilities</Role>
      <ShortName>Other Non-Current Liabilities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>100240 - Disclosure - Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureContingencies</Role>
      <ShortName>Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>100250 - Disclosure - Segment Reporting</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureSegmentReporting</Role>
      <ShortName>Segment Reporting</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>100260 - Disclosure - Earnings Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureEarningsPerShare</Role>
      <ShortName>Earnings Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>100270 - Disclosure - Accumulated Other Comprehensive Income (Loss)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeLoss</Role>
      <ShortName>Accumulated Other Comprehensive Income (Loss)</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>28</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>100280 - Disclosure - Acquisitions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureAcquisitions</Role>
      <ShortName>Acquisitions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>29</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>100290 - Disclosure - Revenue from Contracts with Customers</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureRevenueFromContractsWithCustomers</Role>
      <ShortName>Revenue from Contracts with Customers</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>30</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>100300 - Disclosure - Business Restructuring</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureBusinessRestructuring</Role>
      <ShortName>Business Restructuring</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>31</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>100310 - Disclosure - Insurance Recovery</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureInsuranceRecovery</Role>
      <ShortName>Insurance Recovery</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>32</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>100320 - Disclosure - Customer Claims</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureCustomerClaims</Role>
      <ShortName>Customer Claims</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>33</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>100330 - Disclosure - Statement of Cash Flows - Noncash Investing and Financing Activities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureStatementOfCashFlowsNoncashInvestingAndFinancingActivities</Role>
      <ShortName>Statement of Cash Flows - Noncash Investing and Financing Activities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>34</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>100340 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureSubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>35</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>100350 - Disclosure - Summary of Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Summary of Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureSummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>100360 - Disclosure - Summary of Significant Accounting Policies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesTables</Role>
      <ShortName>Summary of Significant Accounting Policies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureSummaryOfSignificantAccountingPolicies</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>100370 - Disclosure - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureFairValueMeasurementsTables</Role>
      <ShortName>Fair Value Measurements (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureFairValueMeasurements</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>100380 - Disclosure - Goodwill and Other Intangible Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureGoodwillAndOtherIntangibleAssetsTables</Role>
      <ShortName>Goodwill and Other Intangible Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureGoodwillAndOtherIntangibleAssets</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>100390 - Disclosure - Inventories (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureInventoriesTables</Role>
      <ShortName>Inventories (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureInventories</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>100400 - Disclosure - Debt (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureDebtTables</Role>
      <ShortName>Debt (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureDebt</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>100410 - Disclosure - Leases (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureLeasesTables</Role>
      <ShortName>Leases (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureLeases</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>100420 - Disclosure - Other, Net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureOtherNetTables</Role>
      <ShortName>Other, Net (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureOtherNet</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>100430 - Disclosure - Income Taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureIncomeTaxesTables</Role>
      <ShortName>Income Taxes (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureIncomeTaxes</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>100440 - Disclosure - Stock-based Compensation (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureStockBasedCompensationTables</Role>
      <ShortName>Stock-based Compensation (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureStockBasedCompensation</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>100450 - Disclosure - Postretirement Benefit Plans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosurePostretirementBenefitPlansTables</Role>
      <ShortName>Postretirement Benefit Plans (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosurePostretirementBenefitPlans</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>100460 - Disclosure - Accrued Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureAccruedLiabilitiesTables</Role>
      <ShortName>Accrued Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureAccruedLiabilities</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>100470 - Disclosure - Other Non-Current Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureOtherNonCurrentLiabilitiesTables</Role>
      <ShortName>Other Non-Current Liabilities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureOtherNonCurrentLiabilities</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>100480 - Disclosure - Segment Reporting (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureSegmentReportingTables</Role>
      <ShortName>Segment Reporting (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureSegmentReporting</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>100490 - Disclosure - Earnings Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureEarningsPerShareTables</Role>
      <ShortName>Earnings Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureEarningsPerShare</ParentRole>
      <Position>50</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>100500 - Disclosure - Accumulated Other Comprehensive Income (Loss) (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeLossTables</Role>
      <ShortName>Accumulated Other Comprehensive Income (Loss) (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeLoss</ParentRole>
      <Position>51</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>100510 - Disclosure - Acquisitions (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureAcquisitionsTables</Role>
      <ShortName>Acquisitions (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureAcquisitions</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>100520 - Disclosure - Revenue from Contracts with Customers (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureRevenueFromContractsWithCustomersTables</Role>
      <ShortName>Revenue from Contracts with Customers (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureRevenueFromContractsWithCustomers</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>100530 - Disclosure - Summary of Significant Accounting Policies - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesAdditionalInformationDetail</Role>
      <ShortName>Summary of Significant Accounting Policies - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>100540 - Disclosure - Summary of Significant Accounting Policies - Allowance for Doubtful Accounts and Other Accounts Receivable Allowances (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureSummaryOfSignificantAccountingPoliciesAllowanceForDoubtfulAccountsAndOtherAccountsReceivableAllowancesDetail</Role>
      <ShortName>Summary of Significant Accounting Policies - Allowance for Doubtful Accounts and Other Accounts Receivable Allowances (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>100550 - Disclosure - Fair Value Measurements - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureFairValueMeasurementsAdditionalInformationDetail</Role>
      <ShortName>Fair Value Measurements - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>100560 - Disclosure - Fair Value Measurements - Fair Values and Related Carrying Values of Debt (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureFairValueMeasurementsFairValuesAndRelatedCarryingValuesOfDebtDetail</Role>
      <ShortName>Fair Value Measurements - Fair Values and Related Carrying Values of Debt (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>100570 - Disclosure - Fair Value Measurements - Financial Assets and Liabilities, Excluding Cash and Cash Equivalents, Measured on a Recurring Basis at Fair Value (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureFairValueMeasurementsFinancialAssetsAndLiabilitiesExcludingCashAndCashEquivalentsMeasuredOnRecurringBasisAtFairValueDetail</Role>
      <ShortName>Fair Value Measurements - Financial Assets and Liabilities, Excluding Cash and Cash Equivalents, Measured on a Recurring Basis at Fair Value (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>100580 - Disclosure - Derivative Instruments - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureDerivativeInstrumentsAdditionalInformationDetail</Role>
      <ShortName>Derivative Instruments - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>100590 - Disclosure - Goodwill and Other Intangible Assets - Schedule of Changes in Carrying Value of Goodwill (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureGoodwillAndOtherIntangibleAssetsScheduleOfChangesInCarryingValueOfGoodwillDetail</Role>
      <ShortName>Goodwill and Other Intangible Assets - Schedule of Changes in Carrying Value of Goodwill (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>100600 - Disclosure - Goodwill and Other Intangible Assets - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureGoodwillAndOtherIntangibleAssetsAdditionalInformationDetail</Role>
      <ShortName>Goodwill and Other Intangible Assets - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>100610 - Disclosure - Goodwill and Other Intangible Assets - Components of Other Intangible Assets and Changes in Gross Carrying Values (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureGoodwillAndOtherIntangibleAssetsComponentsOfOtherIntangibleAssetsAndChangesInGrossCarryingValuesDetail</Role>
      <ShortName>Goodwill and Other Intangible Assets - Components of Other Intangible Assets and Changes in Gross Carrying Values (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>100620 - Disclosure - Goodwill and Other Intangible Assets - Estimated Amortization Expense for Identifiable Intangibles Assets (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureGoodwillAndOtherIntangibleAssetsEstimatedAmortizationExpenseForIdentifiableIntangiblesAssetsDetail</Role>
      <ShortName>Goodwill and Other Intangible Assets - Estimated Amortization Expense for Identifiable Intangibles Assets (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>100630 - Disclosure - Inventories - Composition of Inventories (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureInventoriesCompositionOfInventoriesDetail</Role>
      <ShortName>Inventories - Composition of Inventories (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>100640 - Disclosure - Debt - Debt (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureDebtDebtDetail</Role>
      <ShortName>Debt - Debt (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>100650 - Disclosure - Debt - Debt (Parenthetical) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureDebtDebtParentheticalDetail</Role>
      <ShortName>Debt - Debt (Parenthetical) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>100660 - Disclosure - Debt - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureDebtAdditionalInformationDetail</Role>
      <ShortName>Debt - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>100670 - Disclosure - Debt - Schedule of Net Interest Expense (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureDebtScheduleOfNetInterestExpenseDetail</Role>
      <ShortName>Debt - Schedule of Net Interest Expense (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>68</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>100680 - Disclosure - Leases - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureLeasesAdditionalInformationDetail</Role>
      <ShortName>Leases - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>69</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>100690 - Disclosure - Leases - Schedule of Lease Cost Included in Cost of Sale and Operating Expenses (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureLeasesScheduleOfLeaseCostIncludedInCostOfSaleAndOperatingExpensesDetail</Role>
      <ShortName>Leases - Schedule of Lease Cost Included in Cost of Sale and Operating Expenses (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>70</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>100700 - Disclosure - Leases - Schedule of Lease Liability Payments (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureLeasesScheduleOfLeaseLiabilityPaymentsDetail</Role>
      <ShortName>Leases - Schedule of Lease Liability Payments (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>71</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>100720 - Disclosure - Leases - Schedule of Operating Leases Weighted Average, Remaining Lease Term and Discount Rate (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureLeasesScheduleOfOperatingLeasesWeightedAverageRemainingLeaseTermAndDiscountRateDetail</Role>
      <ShortName>Leases - Schedule of Operating Leases Weighted Average, Remaining Lease Term and Discount Rate (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>100730 - Disclosure - Other, Net - Other Net in Consolidated Statements of Income (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureOtherNetOtherNetInConsolidatedStatementsOfIncomeDetail</Role>
      <ShortName>Other, Net - Other Net in Consolidated Statements of Income (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>73</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>100740 - Disclosure - Income Taxes - Schedule of Provision for Taxes on Income and Other Related Income Before Taxes (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureIncomeTaxesScheduleOfProvisionForTaxesOnIncomeAndOtherRelatedIncomeBeforeTaxesDetail</Role>
      <ShortName>Income Taxes - Schedule of Provision for Taxes on Income and Other Related Income Before Taxes (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>74</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>100750 - Disclosure - Income Taxes - Summary of Variations Between the Effective and Statutory U.S. Federal Income Tax Rates (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureIncomeTaxesSummaryOfVariationsBetweenEffectiveAndStatutoryUSFederalIncomeTaxRatesDetail</Role>
      <ShortName>Income Taxes - Summary of Variations Between the Effective and Statutory U.S. Federal Income Tax Rates (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>75</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>100760 - Disclosure - Income Taxes - Schedule Showing Tax Effects of Significant Temporary Differences Representing Deferred Tax Assets and Liabilities (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureIncomeTaxesScheduleShowingTaxEffectsOfSignificantTemporaryDifferencesRepresentingDeferredTaxAssetsAndLiabilitiesDetail</Role>
      <ShortName>Income Taxes - Schedule Showing Tax Effects of Significant Temporary Differences Representing Deferred Tax Assets and Liabilities (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>76</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>100780 - Disclosure - Income Taxes - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureIncomeTaxesAdditionalInformationDetail</Role>
      <ShortName>Income Taxes - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>77</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>100790 - Disclosure - Income Taxes - Schedule of Reconciliations of Unrecognized Tax Benefits (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureIncomeTaxesScheduleOfReconciliationsOfUnrecognizedTaxBenefitsDetail</Role>
      <ShortName>Income Taxes - Schedule of Reconciliations of Unrecognized Tax Benefits (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>78</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>100800 - Disclosure - Stockholders' Equity - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureStockholdersEquityAdditionalInformationDetail</Role>
      <ShortName>Stockholders' Equity - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>79</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>100810 - Disclosure - Stock-based Compensation - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureStockBasedCompensationAdditionalInformationDetail</Role>
      <ShortName>Stock-based Compensation - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>80</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>100820 - Disclosure - Stock-based Compensation - Fair Value Assumptions for Stock Options (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureStockBasedCompensationFairValueAssumptionsForStockOptionsDetail</Role>
      <ShortName>Stock-based Compensation - Fair Value Assumptions for Stock Options (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>81</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>100830 - Disclosure - Stock-based Compensation - Summary of Stock Option Activity (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureStockBasedCompensationSummaryOfStockOptionActivityDetail</Role>
      <ShortName>Stock-based Compensation - Summary of Stock Option Activity (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>82</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>100840 - Disclosure - Stock-based Compensation - Summary of Stock Award Activity (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureStockBasedCompensationSummaryOfStockAwardActivityDetail</Role>
      <ShortName>Stock-based Compensation - Summary of Stock Award Activity (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>83</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>100850 - Disclosure - Stock-based Compensation - Summary of SARs Activity (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureStockBasedCompensationSummaryOfSarsActivityDetail</Role>
      <ShortName>Stock-based Compensation - Summary of SARs Activity (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>84</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>100860 - Disclosure - Deferred Compensation - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureDeferredCompensationAdditionalInformationDetail</Role>
      <ShortName>Deferred Compensation - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>85</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>100870 - Disclosure - Postretirement Benefit Plans - Obligations and Funded Status (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosurePostretirementBenefitPlansObligationsAndFundedStatusDetail</Role>
      <ShortName>Postretirement Benefit Plans - Obligations and Funded Status (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>86</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>100880 - Disclosure - Postretirement Benefit Plans - Schedule of Amounts Recognized in Balance Sheets (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosurePostretirementBenefitPlansScheduleOfAmountsRecognizedInBalanceSheetsDetail</Role>
      <ShortName>Postretirement Benefit Plans - Schedule of Amounts Recognized in Balance Sheets (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>87</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R88.htm</HtmlFileName>
      <LongName>100890 - Disclosure - Postretirement Benefit Plans - Amounts Recognized in Accumulated Other Comprehensive Income (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosurePostretirementBenefitPlansAmountsRecognizedInAccumulatedOtherComprehensiveIncomeDetail</Role>
      <ShortName>Postretirement Benefit Plans - Amounts Recognized in Accumulated Other Comprehensive Income (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>88</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R89.htm</HtmlFileName>
      <LongName>100900 - Disclosure - Postretirement Benefit Plans - Information for Pension Plans with Projected Benefit Obligations in Excess of Plan Assets (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosurePostretirementBenefitPlansInformationForPensionPlansWithProjectedBenefitObligationsInExcessOfPlanAssetsDetail</Role>
      <ShortName>Postretirement Benefit Plans - Information for Pension Plans with Projected Benefit Obligations in Excess of Plan Assets (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>89</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R90.htm</HtmlFileName>
      <LongName>100910 - Disclosure - Postretirement Benefit Plans - Components of Net Periodic Benefit Cost (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosurePostretirementBenefitPlansComponentsOfNetPeriodicBenefitCostDetail</Role>
      <ShortName>Postretirement Benefit Plans - Components of Net Periodic Benefit Cost (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>90</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R91.htm</HtmlFileName>
      <LongName>100920 - Disclosure - Postretirement Benefit Plans - Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosurePostretirementBenefitPlansOtherChangesInPlanAssetsAndBenefitObligationsRecognizedInOtherComprehensiveIncomeDetail</Role>
      <ShortName>Postretirement Benefit Plans - Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>91</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R92.htm</HtmlFileName>
      <LongName>100930 - Disclosure - Postretirement Benefit Plans - Estimated Future Benefit Payments (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosurePostretirementBenefitPlansEstimatedFutureBenefitPaymentsDetail</Role>
      <ShortName>Postretirement Benefit Plans - Estimated Future Benefit Payments (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>92</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R93.htm</HtmlFileName>
      <LongName>100940 - Disclosure - Postretirement Benefit Plans - Weighted-Average Assumptions Used To Determine Benefit Obligations (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosurePostretirementBenefitPlansWeightedAverageAssumptionsUsedToDetermineBenefitObligationsDetail</Role>
      <ShortName>Postretirement Benefit Plans - Weighted-Average Assumptions Used To Determine Benefit Obligations (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>93</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R94.htm</HtmlFileName>
      <LongName>100950 - Disclosure - Postretirement Benefit Plans - The Weighted Average Assumptions Used to Determine Net Periodic Benefit Costs (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosurePostretirementBenefitPlansTheWeightedAverageAssumptionsUsedToDetermineNetPeriodicBenefitCostsDetail</Role>
      <ShortName>Postretirement Benefit Plans - The Weighted Average Assumptions Used to Determine Net Periodic Benefit Costs (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>94</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R95.htm</HtmlFileName>
      <LongName>100960 - Disclosure - Postretirement Benefit Plans - Defined Benefit Plans - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosurePostretirementBenefitPlansDefinedBenefitPlansAdditionalInformationDetail</Role>
      <ShortName>Postretirement Benefit Plans - Defined Benefit Plans - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>95</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R96.htm</HtmlFileName>
      <LongName>100970 - Disclosure - Postretirement Benefit Plans - Company's Asset Allocations for its U.S. Pension Plans by Asset Category (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosurePostretirementBenefitPlansCompanySAssetAllocationsForItsUSPensionPlansByAssetCategoryDetail</Role>
      <ShortName>Postretirement Benefit Plans - Company's Asset Allocations for its U.S. Pension Plans by Asset Category (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>96</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R97.htm</HtmlFileName>
      <LongName>100980 - Disclosure - Postretirement Benefit Plans - Company's Asset Allocations for its U.K. Pension Plans by Asset Category (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosurePostretirementBenefitPlansCompanySAssetAllocationsForItsUKPensionPlansByAssetCategoryDetail</Role>
      <ShortName>Postretirement Benefit Plans - Company's Asset Allocations for its U.K. Pension Plans by Asset Category (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>97</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R98.htm</HtmlFileName>
      <LongName>100990 - Disclosure - Postretirement Benefit Plans - Fair Value Changes Within Asset Categories for which Fair Value Measurements Use Significant Unobservable Inputs Level 3 (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosurePostretirementBenefitPlansFairValueChangesWithinAssetCategoriesForWhichFairValueMeasurementsUseSignificantUnobservableInputsLevel3Detail</Role>
      <ShortName>Postretirement Benefit Plans - Fair Value Changes Within Asset Categories for which Fair Value Measurements Use Significant Unobservable Inputs Level 3 (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>98</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R99.htm</HtmlFileName>
      <LongName>101000 - Disclosure - Postretirement Benefit Plans - Defined Contribution Expenses for Company's Qualified Defined Contribution Plans and Statutory Profit Sharing Contributions (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosurePostretirementBenefitPlansDefinedContributionExpensesForCompanySQualifiedDefinedContributionPlansAndStatutoryProfitSharingContributionsDetail</Role>
      <ShortName>Postretirement Benefit Plans - Defined Contribution Expenses for Company's Qualified Defined Contribution Plans and Statutory Profit Sharing Contributions (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>99</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R100.htm</HtmlFileName>
      <LongName>101010 - Disclosure - Postretirement Benefit Plans - Defined Contribution Plans - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosurePostretirementBenefitPlansDefinedContributionPlansAdditionalInformationDetail</Role>
      <ShortName>Postretirement Benefit Plans - Defined Contribution Plans - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>100</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R101.htm</HtmlFileName>
      <LongName>101020 - Disclosure - Accrued Liabilities - Composition of Accrued Liabilities (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureAccruedLiabilitiesCompositionOfAccruedLiabilitiesDetail</Role>
      <ShortName>Accrued Liabilities - Composition of Accrued Liabilities (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>101</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R102.htm</HtmlFileName>
      <LongName>101030 - Disclosure - Other Non-Current Liabilities - Statement of Composition of Other Non Current Liabilities (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureOtherNonCurrentLiabilitiesStatementOfCompositionOfOtherNonCurrentLiabilitiesDetail</Role>
      <ShortName>Other Non-Current Liabilities - Statement of Composition of Other Non Current Liabilities (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>102</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R103.htm</HtmlFileName>
      <LongName>101040 - Disclosure - Contingencies - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureContingenciesAdditionalInformationDetail</Role>
      <ShortName>Contingencies - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>103</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R104.htm</HtmlFileName>
      <LongName>101050 - Disclosure - Segment Reporting - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureSegmentReportingAdditionalInformationDetail</Role>
      <ShortName>Segment Reporting - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>104</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R105.htm</HtmlFileName>
      <LongName>101060 - Disclosure - Segment Reporting - Operating Segment (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureSegmentReportingOperatingSegmentDetail</Role>
      <ShortName>Segment Reporting - Operating Segment (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>105</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R106.htm</HtmlFileName>
      <LongName>101070 - Disclosure - Segment Reporting - Reconciliation of Segment Information to Consolidated Financial Statements (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureSegmentReportingReconciliationOfSegmentInformationToConsolidatedFinancialStatementsDetail</Role>
      <ShortName>Segment Reporting - Reconciliation of Segment Information to Consolidated Financial Statements (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>106</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R107.htm</HtmlFileName>
      <LongName>101080 - Disclosure - Segment Reporting - Summary of Company Wide Geographic Data (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureSegmentReportingSummaryOfCompanyWideGeographicDataDetail</Role>
      <ShortName>Segment Reporting - Summary of Company Wide Geographic Data (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>107</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R108.htm</HtmlFileName>
      <LongName>101090 - Disclosure - Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureEarningsPerShareComputationOfBasicAndDilutedEarningsPerShareDetail</Role>
      <ShortName>Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>108</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R109.htm</HtmlFileName>
      <LongName>101100 - Disclosure - Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Parenthetical) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureEarningsPerShareComputationOfBasicAndDilutedEarningsPerShareParentheticalDetail</Role>
      <ShortName>Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Parenthetical) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>109</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R110.htm</HtmlFileName>
      <LongName>101110 - Disclosure - Accumulated Other Comprehensive Income (Loss) - Summary of Changes in Accumulated Other Comprehensive Income (Loss) (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeLossSummaryOfChangesInAccumulatedOtherComprehensiveIncomeLossDetail</Role>
      <ShortName>Accumulated Other Comprehensive Income (Loss) - Summary of Changes in Accumulated Other Comprehensive Income (Loss) (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeLossTables</ParentRole>
      <Position>110</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R111.htm</HtmlFileName>
      <LongName>101120 - Disclosure - Accumulated Other Comprehensive Income (Loss) - Summary of Amounts Reclassified Out of Accumulated Other Comprehensive Income (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeLossSummaryOfAmountsReclassifiedOutOfAccumulatedOtherComprehensiveIncomeDetail</Role>
      <ShortName>Accumulated Other Comprehensive Income (Loss) - Summary of Amounts Reclassified Out of Accumulated Other Comprehensive Income (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.stepan.com/20201231/taxonomy/role/DisclosureAccumulatedOtherComprehensiveIncomeLossTables</ParentRole>
      <Position>111</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R112.htm</HtmlFileName>
      <LongName>101140 - Disclosure - Acquisitions - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureAcquisitionsAdditionalInformationDetail</Role>
      <ShortName>Acquisitions - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>112</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R113.htm</HtmlFileName>
      <LongName>101150 - Disclosure - Acquisitions - Summary of Purchase Price Allocation for Acquisition (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureAcquisitionsSummaryOfPurchasePriceAllocationForAcquisitionDetail</Role>
      <ShortName>Acquisitions - Summary of Purchase Price Allocation for Acquisition (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>113</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R114.htm</HtmlFileName>
      <LongName>101160 - Disclosure - Acquisitions - Summary of Assets Acquired (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureAcquisitionsSummaryOfAssetsAcquiredDetail</Role>
      <ShortName>Acquisitions - Summary of Assets Acquired (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>114</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R115.htm</HtmlFileName>
      <LongName>101170 - Disclosure - Revenue from Contracts with Customers - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureRevenueFromContractsWithCustomersAdditionalInformationDetail</Role>
      <ShortName>Revenue from Contracts with Customers - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>115</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R116.htm</HtmlFileName>
      <LongName>101180 - Disclosure - Revenue from Contracts with Customers - Summary of Geographic Disaggregation of Net Sales (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureRevenueFromContractsWithCustomersSummaryOfGeographicDisaggregationOfNetSalesDetail</Role>
      <ShortName>Revenue from Contracts with Customers - Summary of Geographic Disaggregation of Net Sales (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>116</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R117.htm</HtmlFileName>
      <LongName>101190 - Disclosure - Business Restructuring - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureBusinessRestructuringAdditionalInformationDetail</Role>
      <ShortName>Business Restructuring - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>117</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R118.htm</HtmlFileName>
      <LongName>101200 - Disclosure - Insurance Recovery - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureInsuranceRecoveryAdditionalInformationDetail</Role>
      <ShortName>Insurance Recovery - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>118</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R119.htm</HtmlFileName>
      <LongName>101210 - Disclosure - Customer Claims - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureCustomerClaimsAdditionalInformationDetail</Role>
      <ShortName>Customer Claims - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>119</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R120.htm</HtmlFileName>
      <LongName>101220 - Disclosure - Statement of Cash Flows - Noncash Investing and Financing Activities - Additional Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureStatementOfCashFlowsNoncashInvestingAndFinancingActivitiesAdditionalInformationDetail</Role>
      <ShortName>Statement of Cash Flows - Noncash Investing and Financing Activities - Additional Information (Detail)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>120</Position>
    </Report>
    <Report instance="scl-10k_20201231.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R121.htm</HtmlFileName>
      <LongName>101230 - Disclosure - Subsequent Events - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.stepan.com/20201231/taxonomy/role/DisclosureSubsequentEventsAdditionalInformationDetails</Role>
      <ShortName>Subsequent Events - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>121</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-K" original="scl-10k_20201231.htm">scl-10k_20201231.htm</File>
    <File>scl-20201231.xsd</File>
    <File>scl-20201231_cal.xml</File>
    <File>scl-20201231_def.xml</File>
    <File>scl-20201231_lab.xml</File>
    <File>scl-20201231_pre.xml</File>
    <File>scl-ex21_9.htm</File>
    <File>scl-ex23_6.htm</File>
    <File>scl-ex24_10.htm</File>
    <File>scl-ex311_8.htm</File>
    <File>scl-ex312_7.htm</File>
    <File>scl-ex32_12.htm</File>
  </InputFiles>
  <SupplementalFiles>
    <File>gel0ccr0ae32000001.jpg</File>
  </SupplementalFiles>
  <BaseTaxonomies>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2020-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/us-gaap/2020-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/srt/2020-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/country/2020-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
