<?xml version='1.0' encoding='utf-8'?>
<FilingSummary>
  <Version>3.20.2</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>392</ContextCount>
  <ElementCount>363</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>84</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>11</UnitCount>
  <MyReports>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0001001 - Document - Cover Page</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/CoverPage</Role>
      <ShortName>Cover Page</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1001002 - Statement - Condensed Consolidated Statements of Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/CondensedConsolidatedStatementsofIncome</Role>
      <ShortName>Condensed Consolidated Statements of Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1002003 - Statement - Condensed Consolidated Statements of Comprehensive Income (Loss)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/CondensedConsolidatedStatementsofComprehensiveIncomeLoss</Role>
      <ShortName>Condensed Consolidated Statements of Comprehensive Income (Loss)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1003004 - Statement - Condensed Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/CondensedConsolidatedBalanceSheets</Role>
      <ShortName>Condensed Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1004005 - Statement - Condensed Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/CondensedConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Condensed Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>1005006 - Statement - Condensed Consolidated Statements of Changes in Stockholders' Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/CondensedConsolidatedStatementsofChangesinStockholdersEquity</Role>
      <ShortName>Condensed Consolidated Statements of Changes in Stockholders' Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>1006007 - Statement - Condensed Consolidated Statements of Changes in Stockholders' Equity (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/CondensedConsolidatedStatementsofChangesinStockholdersEquityParenthetical</Role>
      <ShortName>Condensed Consolidated Statements of Changes in Stockholders' Equity (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>1007008 - Statement - Condensed Consolidated Statements of Cash Flow</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/CondensedConsolidatedStatementsofCashFlow</Role>
      <ShortName>Condensed Consolidated Statements of Cash Flow</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>2101101 - Disclosure - General</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/General</Role>
      <ShortName>General</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>2104102 - Disclosure - Revenue Recognition</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/RevenueRecognition</Role>
      <ShortName>Revenue Recognition</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>2107103 - Disclosure - Other Comprehensive Loss</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/OtherComprehensiveLoss</Role>
      <ShortName>Other Comprehensive Loss</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>2111104 - Disclosure - Business Acquisitions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/BusinessAcquisitions</Role>
      <ShortName>Business Acquisitions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>2117105 - Disclosure - Net Income Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/NetIncomePerShare</Role>
      <ShortName>Net Income Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>2120106 - Disclosure - Inventories</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/Inventories</Role>
      <ShortName>Inventories</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>2123107 - Disclosure - Goodwill</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/Goodwill</Role>
      <ShortName>Goodwill</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>2126108 - Disclosure - Intangible Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/IntangibleAssets</Role>
      <ShortName>Intangible Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>2129109 - Disclosure - Restructuring and Impairment Activities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/RestructuringandImpairmentActivities</Role>
      <ShortName>Restructuring and Impairment Activities</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>2133110 - Disclosure - Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/Debt</Role>
      <ShortName>Debt</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>2138111 - Disclosure - Derivatives</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/Derivatives</Role>
      <ShortName>Derivatives</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>2144112 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/CommitmentsandContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>2146113 - Disclosure - Postretirement and Other Benefits</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/PostretirementandOtherBenefits</Role>
      <ShortName>Postretirement and Other Benefits</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>2149114 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/IncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>2151115 - Disclosure - Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/SegmentInformation</Role>
      <ShortName>Segment Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>2202201 - Disclosure - General (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/GeneralPolicies</Role>
      <ShortName>General (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>2305301 - Disclosure - Revenue Recognition (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/RevenueRecognitionTables</Role>
      <ShortName>Revenue Recognition (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/RevenueRecognition</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>2308302 - Disclosure - Other Comprehensive Loss (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/OtherComprehensiveLossTables</Role>
      <ShortName>Other Comprehensive Loss (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/OtherComprehensiveLoss</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>2312303 - Disclosure - Business Acquisitions (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/BusinessAcquisitionsTables</Role>
      <ShortName>Business Acquisitions (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/BusinessAcquisitions</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>2318304 - Disclosure - Net Income Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/NetIncomePerShareTables</Role>
      <ShortName>Net Income Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/NetIncomePerShare</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>2321305 - Disclosure - Inventories (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/InventoriesTables</Role>
      <ShortName>Inventories (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/Inventories</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>2324306 - Disclosure - Goodwill (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/GoodwillTables</Role>
      <ShortName>Goodwill (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/Goodwill</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>2327307 - Disclosure - Intangible Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/IntangibleAssetsTables</Role>
      <ShortName>Intangible Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/IntangibleAssets</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>2330308 - Disclosure - Restructuring and Impairment Activities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/RestructuringandImpairmentActivitiesTables</Role>
      <ShortName>Restructuring and Impairment Activities (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/RestructuringandImpairmentActivities</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>2334309 - Disclosure - Debt (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/DebtTables</Role>
      <ShortName>Debt (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/Debt</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>2339310 - Disclosure - Derivatives (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/DerivativesTables</Role>
      <ShortName>Derivatives (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/Derivatives</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>2347311 - Disclosure - Postretirement and Other Benefits (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/PostretirementandOtherBenefitsTables</Role>
      <ShortName>Postretirement and Other Benefits (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/PostretirementandOtherBenefits</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>2352312 - Disclosure - Segment Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/SegmentInformationTables</Role>
      <ShortName>Segment Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/SegmentInformation</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>2403401 - Disclosure - General (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/GeneralDetails</Role>
      <ShortName>General (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/GeneralPolicies</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>2406402 - Disclosure - Revenue Recognition (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/RevenueRecognitionDetails</Role>
      <ShortName>Revenue Recognition (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/RevenueRecognitionTables</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>2409403 - Disclosure - Other Comprehensive Loss - Components of Accumulated Comprehensive Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/OtherComprehensiveLossComponentsofAccumulatedComprehensiveIncomeDetails</Role>
      <ShortName>Other Comprehensive Loss - Components of Accumulated Comprehensive Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>2410404 - Disclosure - Other Comprehensive Loss - Changes in Components of Other Comprehensive Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/OtherComprehensiveLossChangesinComponentsofOtherComprehensiveIncomeDetails</Role>
      <ShortName>Other Comprehensive Loss - Changes in Components of Other Comprehensive Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>2413405 - Disclosure - Business Acquisitions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/BusinessAcquisitionsDetails</Role>
      <ShortName>Business Acquisitions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/BusinessAcquisitionsTables</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>2414406 - Disclosure - Business Acquisitions - Schedule of Assets and Liabilities Acquired (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/BusinessAcquisitionsScheduleofAssetsandLiabilitiesAcquiredDetails</Role>
      <ShortName>Business Acquisitions - Schedule of Assets and Liabilities Acquired (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>2415407 - Disclosure - Business Acquisitions - Schedule of Intangible Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/BusinessAcquisitionsScheduleofIntangibleAssetsDetails</Role>
      <ShortName>Business Acquisitions - Schedule of Intangible Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>2416408 - Disclosure - Business Acquisitions - Schedule of Sales and Income from Business Combination (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/BusinessAcquisitionsScheduleofSalesandIncomefromBusinessCombinationDetails</Role>
      <ShortName>Business Acquisitions - Schedule of Sales and Income from Business Combination (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>2419409 - Disclosure - Net Income Per Share (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/NetIncomePerShareDetails</Role>
      <ShortName>Net Income Per Share (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/NetIncomePerShareTables</ParentRole>
      <Position>45</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>2422410 - Disclosure - Inventories (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/InventoriesDetails</Role>
      <ShortName>Inventories (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/InventoriesTables</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>2425411 - Disclosure - Goodwill (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/GoodwillDetails</Role>
      <ShortName>Goodwill (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/GoodwillTables</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>2428412 - Disclosure - Intangible Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/IntangibleAssetsDetails</Role>
      <ShortName>Intangible Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/IntangibleAssetsTables</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>2431413 - Disclosure - Restructuring and Impairment Activities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/RestructuringandImpairmentActivitiesDetails</Role>
      <ShortName>Restructuring and Impairment Activities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/RestructuringandImpairmentActivitiesTables</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>2432414 - Disclosure - Restructuring and Impairment Activities - Restructuring and related charges (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/RestructuringandImpairmentActivitiesRestructuringandrelatedchargesDetails</Role>
      <ShortName>Restructuring and Impairment Activities - Restructuring and related charges (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>2435415 - Disclosure - Debt - Schedule of Debt Summarized (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/DebtScheduleofDebtSummarizedDetails</Role>
      <ShortName>Debt - Schedule of Debt Summarized (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>2436416 - Disclosure - Debt - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/DebtAdditionalInformationDetails</Role>
      <ShortName>Debt - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>2437417 - Disclosure - Debt - Schedule of Principal Repayments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/DebtScheduleofPrincipalRepaymentsDetails</Role>
      <ShortName>Debt - Schedule of Principal Repayments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>2440418 - Disclosure - Derivatives - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/DerivativesAdditionalInformationDetails</Role>
      <ShortName>Derivatives - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>2441419 - Disclosure - Derivatives - Derivatives by Balance Sheet Location (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/DerivativesDerivativesbyBalanceSheetLocationDetails</Role>
      <ShortName>Derivatives - Derivatives by Balance Sheet Location (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>2442420 - Disclosure - Derivatives - Derivative Instruments Effect on AOCI and Results of Operations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/DerivativesDerivativeInstrumentsEffectonAOCIandResultsofOperationsDetails</Role>
      <ShortName>Derivatives - Derivative Instruments Effect on AOCI and Results of Operations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>2443421 - Disclosure - Derivatives - Derivatives Designated as Cash Flow Hedges on Net Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/DerivativesDerivativesDesignatedasCashFlowHedgesonNetIncomeDetails</Role>
      <ShortName>Derivatives - Derivatives Designated as Cash Flow Hedges on Net Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>57</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>2445422 - Disclosure - Commitments and Contingencies (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/CommitmentsandContingenciesDetails</Role>
      <ShortName>Commitments and Contingencies (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/CommitmentsandContingencies</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>2448423 - Disclosure - Postretirement and Other Benefits (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/PostretirementandOtherBenefitsDetails</Role>
      <ShortName>Postretirement and Other Benefits (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/PostretirementandOtherBenefitsTables</ParentRole>
      <Position>59</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>2450424 - Disclosure - Income Taxes (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/IncomeTaxesDetails</Role>
      <ShortName>Income Taxes (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/IncomeTaxes</ParentRole>
      <Position>60</Position>
    </Report>
    <Report instance="swm-20200930.htm">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>2453425 - Disclosure - Segment Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.swmintl.com/role/SegmentInformationDetails</Role>
      <ShortName>Segment Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.swmintl.com/role/SegmentInformationTables</ParentRole>
      <Position>61</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File doctype="10-Q" original="swm-20200930.htm">swm-20200930.htm</File>
    <File>ex31120200930.htm</File>
    <File>ex31220200930.htm</File>
    <File>ex3220200930.htm</File>
    <File>swm-20200930.xsd</File>
    <File>swm-20200930_cal.xml</File>
    <File>swm-20200930_def.xml</File>
    <File>swm-20200930_lab.xml</File>
    <File>swm-20200930_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2019-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/country/2020-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/us-gaap/2020-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://fasb.org/srt/2020-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
