<?xml version="1.0" encoding="utf-8"?>
<FilingSummary xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Version>2.4.0.6</Version>
  <ProcessingTime />
  <ReportFormat>Html</ReportFormat>
  <ContextCount>164</ContextCount>
  <ElementCount>307</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>true</FootnotesReported>
  <SegmentCount>77</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>5</UnitCount>
  <MyReports>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>000 - Disclosure - Document And Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/DocumentAndEntityInformation</Role>
      <ShortName>Document And Entity Information</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>001 - Statement - Condensed Statements of Income (unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/ConsolidatedIncomeStatement</Role>
      <ShortName>Condensed Statements of Income (unaudited)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>002 - Statement - Condensed Statements of Comprehensive Income (unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/ConsolidatedComprehensiveIncome</Role>
      <ShortName>Condensed Statements of Comprehensive Income (unaudited)</ShortName>
    </Report>
    <Report>
      <IsDefault>true</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>003 - Statement - Condensed Balance Sheets (unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/ConsolidatedBalanceSheet</Role>
      <ShortName>Condensed Balance Sheets (unaudited)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>004 - Statement - Condensed Balance Sheets (unaudited) (Parentheticals)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/ConsolidatedBalanceSheet_Parentheticals</Role>
      <ShortName>Condensed Balance Sheets (unaudited) (Parentheticals)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>005 - Statement - Condensed Statements of Cash Flows (unaudited)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/ConsolidatedCashFlow</Role>
      <ShortName>Condensed Statements of Cash Flows (unaudited)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>006 - Disclosure - Note 1 - Description and Basis of Presentation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/Note</Role>
      <ShortName>Note 1 - Description and Basis of Presentation</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>007 - Disclosure - Note 2 - Summary of Significant Accounting Policies and Recent Accounting Pronouncements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/Note0</Role>
      <ShortName>Note 2 - Summary of Significant Accounting Policies and Recent Accounting Pronouncements</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>008 - Disclosure - Note 3 - Acquisitions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/Note00</Role>
      <ShortName>Note 3 - Acquisitions</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>009 - Disclosure - Note 4 - Discontinued Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/Note000</Role>
      <ShortName>Note 4 - Discontinued Operations</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>010 - Disclosure - Note 5 - Stock Benefit Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/Note0000</Role>
      <ShortName>Note 5 - Stock Benefit Plans</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>011 - Disclosure - Note 6 - Marketable Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/Note00000</Role>
      <ShortName>Note 6 - Marketable Securities</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>012 - Disclosure - Note 7 - Fair Value Measurements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/Note000000</Role>
      <ShortName>Note 7 - Fair Value Measurements</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>013 - Disclosure - Note 8 - Long-Lived Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/Note0000000</Role>
      <ShortName>Note 8 - Long-Lived Assets</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>014 - Disclosure - Note 9 - Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/Note00000000</Role>
      <ShortName>Note 9 - Liabilities</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>015 - Disclosure - Note 10 - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/Note000000000</Role>
      <ShortName>Note 10 - Commitments and Contingencies</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>016 - Disclosure - Note 11 - Restructuring Charges</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/Note0000000000</Role>
      <ShortName>Note 11 - Restructuring Charges</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>017 - Disclosure - Note 12 - Interest and Other Income (Expense), Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/Note00000000000</Role>
      <ShortName>Note 12 - Interest and Other Income (Expense), Net</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>018 - Disclosure - Note 13 - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/Note000000000000</Role>
      <ShortName>Note 13 - Income Taxes</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>019 - Disclosure - Note 14 - Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/Note0000000000000</Role>
      <ShortName>Note 14 - Segment Information</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>020 - Disclosure - Note 15 - Net (Loss) Income Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/Note00000000000000</Role>
      <ShortName>Note 15 - Net (Loss) Income Per Share</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>021 - Disclosure - Note 16 - Supplemental Disclosures of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/Note000000000000000</Role>
      <ShortName>Note 16 - Supplemental Disclosures of Cash Flows</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>022 - Disclosure - Note 17 - Related Party Transactions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/Note0000000000000000</Role>
      <ShortName>Note 17 - Related Party Transactions</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>023 - Disclosure - Note 18 - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/Note00000000000000000</Role>
      <ShortName>Note 18 - Subsequent Events</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>024 - Disclosure - Note 3 - Acquisitions (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteTables</Role>
      <ShortName>Note 3 - Acquisitions (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>025 - Disclosure - Note 4 - Discontinued Operations (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteTables0</Role>
      <ShortName>Note 4 - Discontinued Operations (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>026 - Disclosure - Note 5 - Stock Benefit Plans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteTables00</Role>
      <ShortName>Note 5 - Stock Benefit Plans (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>027 - Disclosure - Note 6 - Marketable Securities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteTables000</Role>
      <ShortName>Note 6 - Marketable Securities (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>028 - Disclosure - Note 7 - Fair Value Measurements (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteTables0000</Role>
      <ShortName>Note 7 - Fair Value Measurements (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>029 - Disclosure - Note 8 - Long-Lived Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteTables00000</Role>
      <ShortName>Note 8 - Long-Lived Assets (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>030 - Disclosure - Note 9 - Liabilities (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteTables000000</Role>
      <ShortName>Note 9 - Liabilities (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>031 - Disclosure - Note 10 - Commitments and Contingencies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteTables0000000</Role>
      <ShortName>Note 10 - Commitments and Contingencies (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>032 - Disclosure - Note 12 - Interest and Other Income (Expense), Net (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteTables00000000</Role>
      <ShortName>Note 12 - Interest and Other Income (Expense), Net (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>033 - Disclosure - Note 14 - Segment Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteTables000000000</Role>
      <ShortName>Note 14 - Segment Information (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>034 - Disclosure - Note 15 - Net (Loss) Income Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteTables0000000000</Role>
      <ShortName>Note 15 - Net (Loss) Income Per Share (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>035 - Disclosure - Note 16 - Supplemental Disclosures of Cash Flows (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteTables00000000000</Role>
      <ShortName>Note 16 - Supplemental Disclosures of Cash Flows (Tables)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>036 - Disclosure - Note 1 - Description and Basis of Presentation (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteDetail</Role>
      <ShortName>Note 1 - Description and Basis of Presentation (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>038 - Disclosure - Note 3 - Acquisitions (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteDetail00</Role>
      <ShortName>Note 3 - Acquisitions (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>039 - Disclosure - Note 3 - Acquisitions (Detail) - Purchase Price Allocation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/PurchasePriceAllocationTable</Role>
      <ShortName>Note 3 - Acquisitions (Detail) - Purchase Price Allocation</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>040 - Disclosure - Note 3 - Acquisitions (Detail) - Purchase Price Allocation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/PurchasePriceAllocationTable0</Role>
      <ShortName>Note 3 - Acquisitions (Detail) - Purchase Price Allocation</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>041 - Disclosure - Note 3 - Acquisitions (Detail) - Pro Forma Financial Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/ProFormaFinancialInformationTable</Role>
      <ShortName>Note 3 - Acquisitions (Detail) - Pro Forma Financial Information</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>042 - Disclosure - Note 4 - Discontinued Operations (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteDetail000</Role>
      <ShortName>Note 4 - Discontinued Operations (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>043 - Disclosure - Note 4 - Discontinued Operations (Detail) - Components of Discontinued Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/ComponentsofDiscontinuedOperationsTable</Role>
      <ShortName>Note 4 - Discontinued Operations (Detail) - Components of Discontinued Operations</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>044 - Disclosure - Note 5 - Stock Benefit Plans (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteDetail0000</Role>
      <ShortName>Note 5 - Stock Benefit Plans (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>045 - Disclosure - Note 5 - Stock Benefit Plans (Detail) - Stock Options</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/StockOptionsTable</Role>
      <ShortName>Note 5 - Stock Benefit Plans (Detail) - Stock Options</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>046 - Disclosure - Note 5 - Stock Benefit Plans (Detail) - Restricted Stock Units</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/RestrictedStockUnitsTable</Role>
      <ShortName>Note 5 - Stock Benefit Plans (Detail) - Restricted Stock Units</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>047 - Disclosure - Note 5 - Stock Benefit Plans (Detail) - Stock-based Compensation Expenses</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/StockbasedCompensationExpensesTable</Role>
      <ShortName>Note 5 - Stock Benefit Plans (Detail) - Stock-based Compensation Expenses</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>048 - Disclosure - Note 5 - Stock Benefit Plans (Detail) - Valuation Assumptions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/ValuationAssumptionsTable</Role>
      <ShortName>Note 5 - Stock Benefit Plans (Detail) - Valuation Assumptions</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>049 - Disclosure - Note 6 - Marketable Securities (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteDetail00000</Role>
      <ShortName>Note 6 - Marketable Securities (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>050 - Disclosure - Note 6 - Marketable Securities (Detail) - Portfolio of Marketable Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/PortfolioofMarketableSecuritiesTable</Role>
      <ShortName>Note 6 - Marketable Securities (Detail) - Portfolio of Marketable Securities</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>051 - Disclosure - Note 6 - Marketable Securities (Detail) - Fair Value and Gross Unrealized Losses of the Available for Sale Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/FairValueandGrossUnrealizedLossesoftheAvailableforSaleSecuritiesTable</Role>
      <ShortName>Note 6 - Marketable Securities (Detail) - Fair Value and Gross Unrealized Losses of the Available for Sale Securities</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>052 - Disclosure - Note 6 - Marketable Securities (Detail) - Amortized Cost and Estimated Fair Value of Investments in Available-For-Sale Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/AmortizedCostandEstimatedFairValueofInvestmentsinAvailableForSaleSecuritiesTable</Role>
      <ShortName>Note 6 - Marketable Securities (Detail) - Amortized Cost and Estimated Fair Value of Investments in Available-For-Sale Securities</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>053 - Disclosure - Note 7 - Fair Value Measurements (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteDetail000000</Role>
      <ShortName>Note 7 - Fair Value Measurements (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>054 - Disclosure - Note 7 - Fair Value Measurements (Detail) - Financial Assets Measured at Fair Value on a Recurring Basis</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/FinancialAssetsMeasuredatFairValueonaRecurringBasisTable</Role>
      <ShortName>Note 7 - Fair Value Measurements (Detail) - Financial Assets Measured at Fair Value on a Recurring Basis</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>055 - Disclosure - Note 8 - Long-Lived Assets (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteDetail0000000</Role>
      <ShortName>Note 8 - Long-Lived Assets (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>056 - Disclosure - Note 8 - Long-Lived Assets (Detail) - Property and Equipment, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/PropertyandEquipmentNetTable</Role>
      <ShortName>Note 8 - Long-Lived Assets (Detail) - Property and Equipment, Net</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>057 - Disclosure - Note 8 - Long-Lived Assets (Detail) - Intangible Assets, Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/IntangibleAssetsNetTable</Role>
      <ShortName>Note 8 - Long-Lived Assets (Detail) - Intangible Assets, Net</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>058 - Disclosure - Note 8 - Long-Lived Assets (Detail) - Estimated Aggregate Future Amortization Expense</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/EstimatedAggregateFutureAmortizationExpenseTable</Role>
      <ShortName>Note 8 - Long-Lived Assets (Detail) - Estimated Aggregate Future Amortization Expense</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>059 - Disclosure - Note 8 - Long-Lived Assets (Detail) - Goodwill by Reporting Segment</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/GoodwillbyReportingSegmentTable</Role>
      <ShortName>Note 8 - Long-Lived Assets (Detail) - Goodwill by Reporting Segment</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>060 - Disclosure - Note 9 - Liabilities (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteDetail00000000</Role>
      <ShortName>Note 9 - Liabilities (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>061 - Disclosure - Note 9 - Liabilities (Detail) - Accrued and Other Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/AccruedandOtherLiabilitiesTable</Role>
      <ShortName>Note 9 - Liabilities (Detail) - Accrued and Other Liabilities</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>062 - Disclosure - Note 9 - Liabilities (Detail) - Other Long-Term Liabilities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/OtherLongTermLiabilitiesTable</Role>
      <ShortName>Note 9 - Liabilities (Detail) - Other Long-Term Liabilities</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>063 - Disclosure - Note 9 - Liabilities (Detail) - Future principal payments due on notes payable</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://steelexcel.com/role/FutureprincipalpaymentsdueonnotespayableTable</Role>
      <ShortName>Note 9 - Liabilities (Detail) - Future principal payments due on notes payable</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>065 - Disclosure - Note 10 - Commitments and Contingencies (Detail) - Assumed Operating Leases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/AssumedOperatingLeasesTable</Role>
      <ShortName>Note 10 - Commitments and Contingencies (Detail) - Assumed Operating Leases</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>066 - Disclosure - Note 10 - Commitments and Contingencies (Detail) - Assumed Capital Leases</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/AssumedCapitalLeasesTable</Role>
      <ShortName>Note 10 - Commitments and Contingencies (Detail) - Assumed Capital Leases</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>069 - Disclosure - Note 12 - Interest and Other Income (Expense), Net (Detail) - Interest and Other Income (Expense), Net</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/InterestandOtherIncomeExpenseNetTable</Role>
      <ShortName>Note 12 - Interest and Other Income (Expense), Net (Detail) - Interest and Other Income (Expense), Net</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>070 - Disclosure - Note 13 - Income Taxes (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteDetail000000000000</Role>
      <ShortName>Note 13 - Income Taxes (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>071 - Disclosure - Note 14 - Segment Information (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteDetail0000000000000</Role>
      <ShortName>Note 14 - Segment Information (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>072 - Disclosure - Note 14 - Segment Information (Detail) - Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/SegmentInformationTable</Role>
      <ShortName>Note 14 - Segment Information (Detail) - Segment Information</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>074 - Disclosure - Note 15 - Net (Loss) Income Per Share (Detail) - A Reconciliation of the Numerator and Denominator of the Basic and Diluted Net (Loss) Income Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/AReconciliationoftheNumeratorandDenominatoroftheBasicandDilutedNetLossIncomePerShareTable</Role>
      <ShortName>Note 15 - Net (Loss) Income Per Share (Detail) - A Reconciliation of the Numerator and Denominator of the Basic and Diluted Net (Loss) Income Per Share</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>075 - Disclosure - Note 15 - Net (Loss) Income Per Share (Detail) - Antidilutive Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/AntidilutiveSecuritiesTable</Role>
      <ShortName>Note 15 - Net (Loss) Income Per Share (Detail) - Antidilutive Securities</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>076 - Disclosure - Note 16 - Supplemental Disclosures of Cash Flows (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteDetail000000000000000</Role>
      <ShortName>Note 16 - Supplemental Disclosures of Cash Flows (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>077 - Disclosure - Note 16 - Supplemental Disclosures of Cash Flows (Detail) - Non-cash investing and financing activities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoncashinvestingandfinancingactivitiesTable</Role>
      <ShortName>Note 16 - Supplemental Disclosures of Cash Flows (Detail) - Non-cash investing and financing activities</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>078 - Disclosure - Note 17 - Related Party Transactions (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteDetail0000000000000000</Role>
      <ShortName>Note 17 - Related Party Transactions (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>079 - Disclosure - Note 18 - Subsequent Events (Detail)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://steelexcel.com/role/NoteDetail00000000000000000</Role>
      <ShortName>Note 18 - Subsequent Events (Detail)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <Logs>
    <Log type="Info">Element us-gaap_CashAndCashEquivalentsFairValueDisclosure had a mix of decimals attribute values: -5 -3.</Log>
    <Log type="Info">Element us-gaap_CommonStockParOrStatedValuePerShare had a mix of decimals attribute values: 2 3.</Log>
    <Log type="Info">Element us-gaap_EquityMethodInvestmentOwnershipPercentage had a mix of decimals attribute values: 2 3.</Log>
    <Log type="Info">Element us-gaap_IncomeTaxExpenseBenefit had a mix of decimals attribute values: -5 -3.</Log>
    <Log type="Info">Element us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber had a mix of decimals attribute values: -3 0.</Log>
    <Log type="Info">Element us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber had a mix of decimals attribute values: -3 0.</Log>
    <Log type="Info">'Monetary' elements on report '038 - Disclosure - Note 3 - Acquisitions (Detail)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '055 - Disclosure - Note 8 - Long-Lived Assets (Detail)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '070 - Disclosure - Note 13 - Income Taxes (Detail)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">'Monetary' elements on report '078 - Disclosure - Note 17 - Related Party Transactions (Detail)' had a mix of different decimal attribute values.</Log>
    <Log type="Info">Process Flow-Through: 001 - Statement - Condensed Statements of Income (unaudited)</Log>
    <Log type="Info">Process Flow-Through: 002 - Statement - Condensed Statements of Comprehensive Income (unaudited)</Log>
    <Log type="Info">Process Flow-Through: 003 - Statement - Condensed Balance Sheets (unaudited)</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Sep. 30, 2011'</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Dec. 31, 2010'</Log>
    <Log type="Info">Process Flow-Through: 004 - Statement - Condensed Balance Sheets (unaudited) (Parentheticals)</Log>
    <Log type="Info">Process Flow-Through: 005 - Statement - Condensed Statements of Cash Flows (unaudited)</Log>
  </Logs>
  <InputFiles>
    <File>sxcl-20120930.xml</File>
    <File>sxcl-20120930.xsd</File>
    <File>sxcl-20120930_cal.xml</File>
    <File>sxcl-20120930_def.xml</File>
    <File>sxcl-20120930_lab.xml</File>
    <File>sxcl-20120930_pre.xml</File>
  </InputFiles>
  <SupplementalFiles />
  <BaseTaxonomies />
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
