<?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>88</ContextCount>
  <ElementCount>248</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>15</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>4</UnitCount>
  <MyReports>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>00090 - Document - Document And Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document And Entity Information</ShortName>
    </Report>
    <Report>
      <IsDefault>true</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>00100 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/StatementConsolidatedBalanceSheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>00105 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/StatementConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>00200 - Statement - Consolidated Statements Of Operations And Comprehensive ( Loss) Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/StatementConsolidatedStatementsOfOperationsAndComprehensiveLossIncome</Role>
      <ShortName>Consolidated Statements Of Operations And Comprehensive ( Loss) Income</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>00300 - Statement - Consolidated Statement Of Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/StatementConsolidatedStatementOfEquity</Role>
      <ShortName>Consolidated Statement Of Equity</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>00305 - Statement - Consolidated Statement Of Equity (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/StatementConsolidatedStatementOfEquityParenthetical</Role>
      <ShortName>Consolidated Statement Of Equity (Parenthetical)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>00400 - Statement - Consolidated Statements Of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/StatementConsolidatedStatementsOfCashFlows</Role>
      <ShortName>Consolidated Statements Of Cash Flows</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>00405 - Statement - Consolidated Statements Of Cash Flows (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/StatementConsolidatedStatementsOfCashFlowsParenthetical</Role>
      <ShortName>Consolidated Statements Of Cash Flows (Parenthetical)</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>10101 - Disclosure - Basis Of Presentation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureBasisOfPresentation</Role>
      <ShortName>Basis Of Presentation</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>10201 - Statement - Organization</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/StatementOrganization</Role>
      <ShortName>Organization</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>10301 - Disclosure - Summary Of Significant Accounting Policies And Adoption Of New Accounting Pronouncements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureSummaryOfSignificantAccountingPoliciesAndAdoptionOfNewAccountingPronouncements</Role>
      <ShortName>Summary Of Significant Accounting Policies And Adoption Of New Accounting Pronouncements</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>10401 - Disclosure - Business Combination</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureBusinessCombination</Role>
      <ShortName>Business Combination</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>10501 - Disclosure - Notes Receivable</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureNotesReceivable</Role>
      <ShortName>Notes Receivable</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>10601 - Disclosure - Real Estate</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureRealEstate</Role>
      <ShortName>Real Estate</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>10701 - Disclosure - Investments In Joint Ventures</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureInvestmentsInJointVentures</Role>
      <ShortName>Investments In Joint Ventures</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>10801 - Disclosure - Real Estate Available For Sale</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureRealEstateAvailableForSale</Role>
      <ShortName>Real Estate Available For Sale</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>10901 - Disclosure - Investment In Loan Pool Participation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureInvestmentInLoanPoolParticipation</Role>
      <ShortName>Investment In Loan Pool Participation</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>11001 - Disclosure - Marketable Securities</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureMarketableSecurities</Role>
      <ShortName>Marketable Securities</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>11101 - Disclosure - Fair Value Measurements And The Fair Value Option</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureFairValueMeasurementsAndFairValueOption</Role>
      <ShortName>Fair Value Measurements And The Fair Value Option</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>11201 - Disclosure - Senior Notes</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureSeniorNotes</Role>
      <ShortName>Senior Notes</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>11301 - Disclosure - Other Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureOtherAssets</Role>
      <ShortName>Other Assets</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>11401 - Disclosure - Line Of Credit</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureLineOfCredit</Role>
      <ShortName>Line Of Credit</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>11501 - Disclosure - Notes Payable And Junior Subordinated Debentures</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureNotesPayableAndJuniorSubordinatedDebentures</Role>
      <ShortName>Notes Payable And Junior Subordinated Debentures</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>11601 - Disclosure - Notes Payable</LongName>
      <ReportType>Notes</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureNotesPayable</Role>
      <ShortName>Notes Payable</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>11701 - Disclosure - Junior Subordinated Debentures</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureJuniorSubordinatedDebentures</Role>
      <ShortName>Junior Subordinated Debentures</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>11801 - Disclosure - Mortgage Loans Payable</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureMortgageLoansPayable</Role>
      <ShortName>Mortgage Loans Payable</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>11901 - Disclosure - Convertible Subordinated Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureConvertibleSubordinatedDebt</Role>
      <ShortName>Convertible Subordinated Debt</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>12001 - Disclosure - Related Party Transactions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureRelatedPartyTransactions</Role>
      <ShortName>Related Party Transactions</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>12101 - Disclosure - Earnings Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureEarningsPerShare</Role>
      <ShortName>Earnings Per Share</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>12201 - Disclosure - Capital Stock</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureCapitalStock</Role>
      <ShortName>Capital Stock</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>12301 - Disclosure - Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureSegmentInformation</Role>
      <ShortName>Segment Information</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>12401 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureIncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>12501 - Disclosure - Subsequent Events</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureSubsequentEvents</Role>
      <ShortName>Subsequent Events</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>12601 - Disclosure - Guarantor And Non-Guarantor Financial Statements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureGuarantorAndNonGuarantorFinancialStatements</Role>
      <ShortName>Guarantor And Non-Guarantor Financial Statements</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>12701 - Disclosure - Commitments And Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureCommitmentsAndContingencies</Role>
      <ShortName>Commitments And Contingencies</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>12801 - Disclosure - Stock Compensation Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureStockCompensationPlans</Role>
      <ShortName>Stock Compensation Plans</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>12901 - Disclosure - Employee Benefit Arrangements</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureEmployeeBenefitArrangements</Role>
      <ShortName>Employee Benefit Arrangements</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>13001 - Disclosure - Unaudited Quarterly Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureUnauditedQuarterlyInformation</Role>
      <ShortName>Unaudited Quarterly Information</ShortName>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>13101 - Disclosure - Schedule III - Real Estate And Accumulated Depreciation</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.kennedywilson.com/role/DisclosureScheduleIiiRealEstateAndAccumulatedDepreciation</Role>
      <ShortName>Schedule III - Real Estate And Accumulated Depreciation</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_PreferredStockDividendRatePercentage had a mix of decimals attribute values: 0 4.</Log>
    <Log type="Info">Process Flow-Through: 00100 - Statement - Consolidated Balance Sheets</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Sep. 30, 2010'</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Dec. 31, 2008'</Log>
    <Log type="Info">	Process Flow-Through: Removing column 'Dec. 31, 2007'</Log>
    <Log type="Info">Process Flow-Through: 00105 - Statement - Consolidated Balance Sheets (Parenthetical)</Log>
    <Log type="Info">Process Flow-Through: 00200 - Statement - Consolidated Statements Of Operations And Comprehensive ( Loss) Income</Log>
    <Log type="Info">Process Flow-Through: 00305 - Statement - Consolidated Statement Of Equity (Parenthetical)</Log>
    <Log type="Info">	Process Flow-Through: Removing column '9 Months Ended
Sep. 30, 2010'</Log>
    <Log type="Info">Process Flow-Through: 00400 - Statement - Consolidated Statements Of Cash Flows</Log>
    <Log type="Info">Process Flow-Through: 00405 - Statement - Consolidated Statements Of Cash Flows (Parenthetical)</Log>
    <Log type="Info">Process Flow-Through: 10201 - Statement - Organization</Log>
  </Logs>
  <InputFiles>
    <File>kw-20110930.xml</File>
    <File>kw-20110930.xsd</File>
    <File>kw-20110930_cal.xml</File>
    <File>kw-20110930_def.xml</File>
    <File>kw-20110930_lab.xml</File>
    <File>kw-20110930_pre.xml</File>
  </InputFiles>
  <SupplementalFiles />
  <BaseTaxonomies />
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
