<?xml version='1.0' encoding='UTF-8'?>
<FilingSummary>
  <Version>3.10.0.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>374</ContextCount>
  <ElementCount>331</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>99</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>11</UnitCount>
  <MyReports>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>0001000 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/DocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>1001000 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/CondensedConsolidatedStatementsOfOperationsAndComprehensiveIncomeLossUnaudited</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME (LOSS) (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>1002000 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/CondensedConsolidatedBalanceSheetsUnaudited</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>1002500 - Statement - CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/CondensedConsolidatedBalanceSheetsUnauditedParenthetical</Role>
      <ShortName>CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>1003000 - Statement - CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/CondensedConsolidatedStatementsOfCashFlowsUnaudited</Role>
      <ShortName>CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>2101100 - Disclosure - BASIS OF PRESENTATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/BasisOfPresentation</Role>
      <ShortName>BASIS OF PRESENTATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>2102100 - Disclosure - NEW ACCOUNTING PRONOUNCEMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/NewAccountingPronouncements</Role>
      <ShortName>NEW ACCOUNTING PRONOUNCEMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>2103100 - Disclosure - AQUISITIONS AND DISCONTINUED OPERATIONS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/AquisitionsAndDiscontinuedOperations</Role>
      <ShortName>AQUISITIONS AND DISCONTINUED OPERATIONS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>2104100 - Disclosure - REVENUES FROM CONTRACTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/RevenuesFromContracts</Role>
      <ShortName>REVENUES FROM CONTRACTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>2105100 - Disclosure - INFORMATION ON REPORTABLE SEGMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/InformationOnReportableSegments</Role>
      <ShortName>INFORMATION ON REPORTABLE SEGMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>2106100 - Disclosure - SPECIAL CHARGES, NET</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/SpecialChargesNet</Role>
      <ShortName>SPECIAL CHARGES, NET</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>2107100 - Disclosure - INVENTORIES, NET</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/InventoriesNet</Role>
      <ShortName>INVENTORIES, NET</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>2108100 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/GoodwillAndOtherIntangibleAssets</Role>
      <ShortName>GOODWILL AND OTHER INTANGIBLE ASSETS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>2109100 - Disclosure - WARRANTY</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/Warranty</Role>
      <ShortName>WARRANTY</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>2110100 - Disclosure - EMPLOYEE BENEFIT PLANS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/EmployeeBenefitPlans</Role>
      <ShortName>EMPLOYEE BENEFIT PLANS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>2111100 - Disclosure - INDEBTEDNESS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/Indebtedness</Role>
      <ShortName>INDEBTEDNESS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>2112100 - Disclosure - DERIVATIVE FINANCIAL INSTRUMENTS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/DerivativeFinancialInstruments</Role>
      <ShortName>DERIVATIVE FINANCIAL INSTRUMENTS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>2113100 - Disclosure - EQUITY AND LONG-TERM INCENTIVE COMPENSATION</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/EquityAndLongTermIncentiveCompensation</Role>
      <ShortName>EQUITY AND LONG-TERM INCENTIVE COMPENSATION</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>2114100 - Disclosure - CONTINGENT LIABILITIES AND OTHER MATTERS</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/ContingentLiabilitiesAndOtherMatters</Role>
      <ShortName>CONTINGENT LIABILITIES AND OTHER MATTERS</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>2115100 - Disclosure - INCOME TAXES</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/IncomeTaxes</Role>
      <ShortName>INCOME TAXES</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>2116100 - Disclosure - FAIR VALUE</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/FairValue</Role>
      <ShortName>FAIR VALUE</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>2201201 - Disclosure - BASIS OF PRESENTATION (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/BasisOfPresentationPolicies</Role>
      <ShortName>BASIS OF PRESENTATION (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>2302301 - Disclosure - NEW ACCOUNTING PRONOUNCEMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/NewAccountingPronouncementsTables</Role>
      <ShortName>NEW ACCOUNTING PRONOUNCEMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.spx.com/role/NewAccountingPronouncements</ParentRole>
      <Position>23</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>2303301 - Disclosure - AQUISITIONS AND DISCONTINUED OPERATIONS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/AquisitionsAndDiscontinuedOperationsTables</Role>
      <ShortName>AQUISITIONS AND DISCONTINUED OPERATIONS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.spx.com/role/AquisitionsAndDiscontinuedOperations</ParentRole>
      <Position>24</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>2304301 - Disclosure - REVENUES FROM CONTRACTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/RevenuesFromContractsTables</Role>
      <ShortName>REVENUES FROM CONTRACTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.spx.com/role/RevenuesFromContracts</ParentRole>
      <Position>25</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>2305301 - Disclosure - INFORMATION ON REPORTABLE SEGMENTS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/InformationOnReportableSegmentsTables</Role>
      <ShortName>INFORMATION ON REPORTABLE SEGMENTS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.spx.com/role/InformationOnReportableSegments</ParentRole>
      <Position>26</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>2306301 - Disclosure - SPECIAL CHARGES, NET (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/SpecialChargesNetTables</Role>
      <ShortName>SPECIAL CHARGES, NET (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.spx.com/role/SpecialChargesNet</ParentRole>
      <Position>27</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>2307301 - Disclosure - INVENTORIES, NET (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/InventoriesNetTables</Role>
      <ShortName>INVENTORIES, NET (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.spx.com/role/InventoriesNet</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>2308301 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/GoodwillAndOtherIntangibleAssetsTables</Role>
      <ShortName>GOODWILL AND OTHER INTANGIBLE ASSETS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.spx.com/role/GoodwillAndOtherIntangibleAssets</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>2309301 - Disclosure - WARRANTY (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/WarrantyTables</Role>
      <ShortName>WARRANTY (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.spx.com/role/Warranty</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>2310301 - Disclosure - EMPLOYEE BENEFIT PLANS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/EmployeeBenefitPlansTables</Role>
      <ShortName>EMPLOYEE BENEFIT PLANS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.spx.com/role/EmployeeBenefitPlans</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>2311301 - Disclosure - INDEBTEDNESS (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/IndebtednessTables</Role>
      <ShortName>INDEBTEDNESS (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.spx.com/role/Indebtedness</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>2313301 - Disclosure - EQUITY AND LONG-TERM INCENTIVE COMPENSATION (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/EquityAndLongTermIncentiveCompensationTables</Role>
      <ShortName>EQUITY AND LONG-TERM INCENTIVE COMPENSATION (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.spx.com/role/EquityAndLongTermIncentiveCompensation</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>2316301 - Disclosure - FAIR VALUE (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/FairValueTables</Role>
      <ShortName>FAIR VALUE (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.spx.com/role/FairValue</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>2401402 - Disclosure - BASIS OF PRESENTATION (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/BasisOfPresentationDetails</Role>
      <ShortName>BASIS OF PRESENTATION (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.spx.com/role/BasisOfPresentationPolicies</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>2402402 - Disclosure - NEW ACCOUNTING PRONOUNCEMENTS - Cumulative Effect on Balance Sheet (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/NewAccountingPronouncementsCumulativeEffectOnBalanceSheetDetails</Role>
      <ShortName>NEW ACCOUNTING PRONOUNCEMENTS - Cumulative Effect on Balance Sheet (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>36</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>2403402 - Disclosure - AQUISITIONS AND DISCONTINUED OPERATIONS - Business Acquisition (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/AquisitionsAndDiscontinuedOperationsBusinessAcquisitionDetails</Role>
      <ShortName>AQUISITIONS AND DISCONTINUED OPERATIONS - Business Acquisition (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>37</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>2403403 - Disclosure - AQUISITIONS AND DISCONTINUED OPERATIONS - Schedule of Assets and Liabilities Acquired and Assumed (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/AquisitionsAndDiscontinuedOperationsScheduleOfAssetsAndLiabilitiesAcquiredAndAssumedDetails</Role>
      <ShortName>AQUISITIONS AND DISCONTINUED OPERATIONS - Schedule of Assets and Liabilities Acquired and Assumed (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>38</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>2403404 - Disclosure - AQUISITIONS AND DISCONTINUED OPERATIONS - Pro Forma Results (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/AquisitionsAndDiscontinuedOperationsProFormaResultsDetails</Role>
      <ShortName>AQUISITIONS AND DISCONTINUED OPERATIONS - Pro Forma Results (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>39</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>2403405 - Disclosure - AQUISITIONS AND DISCONTINUED OPERATIONS - Discontinued Operations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/AquisitionsAndDiscontinuedOperationsDiscontinuedOperationsDetails</Role>
      <ShortName>AQUISITIONS AND DISCONTINUED OPERATIONS - Discontinued Operations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>40</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>2404402 - Disclosure - REVENUES FROM CONTRACTS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/RevenuesFromContractsNarrativeDetails</Role>
      <ShortName>REVENUES FROM CONTRACTS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>41</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>2404403 - Disclosure - REVENUES FROM CONTRACTS - Disaggregated Revenue (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/RevenuesFromContractsDisaggregatedRevenueDetails</Role>
      <ShortName>REVENUES FROM CONTRACTS - Disaggregated Revenue (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>42</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>2404404 - Disclosure - REVENUES FROM CONTRACTS - Contract Balances (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/RevenuesFromContractsContractBalancesDetails</Role>
      <ShortName>REVENUES FROM CONTRACTS - Contract Balances (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>43</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>2404405 - Disclosure - REVENUES FROM CONTRACTS - Statement of Operations and Comprehensive Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/RevenuesFromContractsStatementOfOperationsAndComprehensiveIncomeDetails</Role>
      <ShortName>REVENUES FROM CONTRACTS - Statement of Operations and Comprehensive Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>44</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>2404406 - Disclosure - REVENUES FROM CONTRACTS - Balance Sheet (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/RevenuesFromContractsBalanceSheetDetails</Role>
      <ShortName>REVENUES FROM CONTRACTS - Balance Sheet (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>2405402 - Disclosure - INFORMATION ON REPORTABLE SEGMENTS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/InformationOnReportableSegmentsDetails</Role>
      <ShortName>INFORMATION ON REPORTABLE SEGMENTS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.spx.com/role/InformationOnReportableSegmentsTables</ParentRole>
      <Position>46</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>2406402 - Disclosure - SPECIAL CHARGES, NET (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/SpecialChargesNetDetails</Role>
      <ShortName>SPECIAL CHARGES, NET (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.spx.com/role/SpecialChargesNetTables</ParentRole>
      <Position>47</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>2407402 - Disclosure - INVENTORIES, NET (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/InventoriesNetDetails</Role>
      <ShortName>INVENTORIES, NET (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.spx.com/role/InventoriesNetTables</ParentRole>
      <Position>48</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>2408402 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/GoodwillAndOtherIntangibleAssetsDetails</Role>
      <ShortName>GOODWILL AND OTHER INTANGIBLE ASSETS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.spx.com/role/GoodwillAndOtherIntangibleAssetsTables</ParentRole>
      <Position>49</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>2408403 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS - Other Intangibles, Net (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/GoodwillAndOtherIntangibleAssetsOtherIntangiblesNetDetails</Role>
      <ShortName>GOODWILL AND OTHER INTANGIBLE ASSETS - Other Intangibles, Net (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>2408404 - Disclosure - GOODWILL AND OTHER INTANGIBLE ASSETS - Narrative (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/GoodwillAndOtherIntangibleAssetsNarrativeDetails</Role>
      <ShortName>GOODWILL AND OTHER INTANGIBLE ASSETS - Narrative (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>2409402 - Disclosure - WARRANTY (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/WarrantyDetails</Role>
      <ShortName>WARRANTY (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.spx.com/role/WarrantyTables</ParentRole>
      <Position>52</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>2410402 - Disclosure - EMPLOYEE BENEFIT PLANS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/EmployeeBenefitPlansDetails</Role>
      <ShortName>EMPLOYEE BENEFIT PLANS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.spx.com/role/EmployeeBenefitPlansTables</ParentRole>
      <Position>53</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>2411402 - Disclosure - INDEBTEDNESS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/IndebtednessDetails</Role>
      <ShortName>INDEBTEDNESS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.spx.com/role/IndebtednessTables</ParentRole>
      <Position>54</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>2411403 - Disclosure - INDEBTEDNESS - Senior Credit Facilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/IndebtednessSeniorCreditFacilitiesDetails</Role>
      <ShortName>INDEBTEDNESS - Senior Credit Facilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>2412401 - Disclosure - DERIVATIVE FINANCIAL INSTRUMENTS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/DerivativeFinancialInstrumentsDetails</Role>
      <ShortName>DERIVATIVE FINANCIAL INSTRUMENTS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.spx.com/role/DerivativeFinancialInstruments</ParentRole>
      <Position>56</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>2413402 - Disclosure - EQUITY AND LONG-TERM INCENTIVE COMPENSATION (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/EquityAndLongTermIncentiveCompensationDetails</Role>
      <ShortName>EQUITY AND LONG-TERM INCENTIVE COMPENSATION (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.spx.com/role/EquityAndLongTermIncentiveCompensationTables</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>2413403 - Disclosure - EQUITY AND LONG-TERM INCENTIVE COMPENSATION - Long Term Incentive Compensation (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/EquityAndLongTermIncentiveCompensationLongTermIncentiveCompensationDetails</Role>
      <ShortName>EQUITY AND LONG-TERM INCENTIVE COMPENSATION - Long Term Incentive Compensation (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>58</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>2413406 - Disclosure - EQUITY AND LONG-TERM INCENTIVE COMPENSATION - Accumulated Other Comprehensive Income (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/EquityAndLongTermIncentiveCompensationAccumulatedOtherComprehensiveIncomeDetails</Role>
      <ShortName>EQUITY AND LONG-TERM INCENTIVE COMPENSATION - Accumulated Other Comprehensive Income (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>2413407 - Disclosure - EQUITY AND LONG-TERM INCENTIVE COMPENSATION - Components of AOCI (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/EquityAndLongTermIncentiveCompensationComponentsOfAociDetails</Role>
      <ShortName>EQUITY AND LONG-TERM INCENTIVE COMPENSATION - Components of AOCI (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>2413408 - Disclosure - EQUITY AND LONG-TERM INCENTIVE COMPENSATION - Common Stock in Treasury (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/EquityAndLongTermIncentiveCompensationCommonStockInTreasuryDetails</Role>
      <ShortName>EQUITY AND LONG-TERM INCENTIVE COMPENSATION - Common Stock in Treasury (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>2413409 - Disclosure - EQUITY AND LONG-TERM INCENTIVE COMPENSATION - Changes in Equity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/EquityAndLongTermIncentiveCompensationChangesInEquityDetails</Role>
      <ShortName>EQUITY AND LONG-TERM INCENTIVE COMPENSATION - Changes in Equity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>2414401 - Disclosure - CONTINGENT LIABILITIES AND OTHER MATTERS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/ContingentLiabilitiesAndOtherMattersDetails</Role>
      <ShortName>CONTINGENT LIABILITIES AND OTHER MATTERS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.spx.com/role/ContingentLiabilitiesAndOtherMatters</ParentRole>
      <Position>63</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>2414402 - Disclosure - CONTINGENT LIABILITIES AND OTHER MATTERS - Noncontrolling Interest in South African Subsidiary (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/ContingentLiabilitiesAndOtherMattersNoncontrollingInterestInSouthAfricanSubsidiaryDetails</Role>
      <ShortName>CONTINGENT LIABILITIES AND OTHER MATTERS - Noncontrolling Interest in South African Subsidiary (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>2414403 - Disclosure - CONTINGENT LIABILITIES AND OTHER MATTERS - Environmental Matters (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/ContingentLiabilitiesAndOtherMattersEnvironmentalMattersDetails</Role>
      <ShortName>CONTINGENT LIABILITIES AND OTHER MATTERS - Environmental Matters (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>2415401 - Disclosure - INCOME TAXES (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/IncomeTaxesDetails</Role>
      <ShortName>INCOME TAXES (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.spx.com/role/IncomeTaxes</ParentRole>
      <Position>66</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>2416402 - Disclosure - FAIR VALUE (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/FairValueDetails</Role>
      <ShortName>FAIR VALUE (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.spx.com/role/FairValueTables</ParentRole>
      <Position>67</Position>
    </Report>
    <Report instance="spxc-20180630.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>2416403 - Disclosure - FAIR VALUE - Changes in Liability ans Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.spx.com/role/FairValueChangesInLiabilityAnsAssetsDetails</Role>
      <ShortName>FAIR VALUE - Changes in Liability ans Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>68</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>spxc-20180630.xml</File>
    <File>spxc-20180630.xsd</File>
    <File>spxc-20180630_cal.xml</File>
    <File>spxc-20180630_def.xml</File>
    <File>spxc-20180630_lab.xml</File>
    <File>spxc-20180630_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies>
    <BaseTaxonomy>http://fasb.org/us-gaap/2017-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/dei/2014-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/invest/2013-01-31</BaseTaxonomy>
    <BaseTaxonomy>http://xbrl.sec.gov/country/2017-01-31</BaseTaxonomy>
  </BaseTaxonomies>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
