<?xml version='1.0' encoding='UTF-8'?>
<FilingSummary>
  <Version>3.7.0.1</Version>
  <ProcessingTime/>
  <ReportFormat>html</ReportFormat>
  <ContextCount>429</ContextCount>
  <ElementCount>549</ElementCount>
  <EntityCount>1</EntityCount>
  <FootnotesReported>false</FootnotesReported>
  <SegmentCount>144</SegmentCount>
  <ScenarioCount>0</ScenarioCount>
  <TuplesReported>false</TuplesReported>
  <UnitCount>9</UnitCount>
  <MyReports>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R1.htm</HtmlFileName>
      <LongName>00090 - Document - Document and Entity Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DocumentDocumentAndEntityInformation</Role>
      <ShortName>Document and Entity Information</ShortName>
      <MenuCategory>Cover</MenuCategory>
      <Position>1</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R2.htm</HtmlFileName>
      <LongName>00100 - Statement - Consolidated Balance Sheets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/StatementConsolidatedBalanceSheets</Role>
      <ShortName>Consolidated Balance Sheets</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>2</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R3.htm</HtmlFileName>
      <LongName>00105 - Statement - Consolidated Balance Sheets (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/StatementConsolidatedBalanceSheetsParenthetical</Role>
      <ShortName>Consolidated Balance Sheets (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>3</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R4.htm</HtmlFileName>
      <LongName>00200 - Statement - Consolidated Statements of Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/StatementConsolidatedStatementsOfOperations</Role>
      <ShortName>Consolidated Statements of Operations</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>4</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R5.htm</HtmlFileName>
      <LongName>00205 - Statement - Consolidated Statements of Operations (Parenthetical)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/StatementConsolidatedStatementsOfOperationsParenthetical</Role>
      <ShortName>Consolidated Statements of Operations (Parenthetical)</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>5</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R6.htm</HtmlFileName>
      <LongName>00300 - Statement - Consolidated Statements of Comprehensive (Loss) Income</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/StatementConsolidatedStatementsOfComprehensiveLossIncome</Role>
      <ShortName>Consolidated Statements of Comprehensive (Loss) Income</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>6</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R7.htm</HtmlFileName>
      <LongName>00400 - Statement - Consolidated Statements of Stockholders Equity</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/StatementConsolidatedStatementsOfStockholdersEquity</Role>
      <ShortName>Consolidated Statements of Stockholders Equity</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>7</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R8.htm</HtmlFileName>
      <LongName>00500 - Statement - Consolidated Statements of Cash Flows</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/StatementConsolidatedStatementsOfCashFlows</Role>
      <ShortName>Consolidated Statements of Cash Flows</ShortName>
      <MenuCategory>Statements</MenuCategory>
      <Position>8</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R9.htm</HtmlFileName>
      <LongName>10101 - Disclosure - Summary of Business and Significant Accounting Policies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSummaryOfBusinessAndSignificantAccountingPolicies</Role>
      <ShortName>Summary of Business and Significant Accounting Policies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>9</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R10.htm</HtmlFileName>
      <LongName>10201 - Disclosure - Changes in Project-Related Estimates</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureChangesInProjectRelatedEstimates</Role>
      <ShortName>Changes in Project-Related Estimates</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>10</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R11.htm</HtmlFileName>
      <LongName>10301 - Disclosure - Preferred Stock Issuance</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosurePreferredStockIssuance</Role>
      <ShortName>Preferred Stock Issuance</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>11</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R12.htm</HtmlFileName>
      <LongName>10401 - Disclosure - Variable Interest Entities and Equity Method Investments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureVariableInterestEntitiesAndEquityMethodInvestments</Role>
      <ShortName>Variable Interest Entities and Equity Method Investments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>12</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R13.htm</HtmlFileName>
      <LongName>10501 - Disclosure - Property, Plant and Equipment</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosurePropertyPlantAndEquipment</Role>
      <ShortName>Property, Plant and Equipment</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>13</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R14.htm</HtmlFileName>
      <LongName>10601 - Disclosure - Receivables</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureReceivables</Role>
      <ShortName>Receivables</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>14</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R15.htm</HtmlFileName>
      <LongName>10701 - Disclosure - Acquisitions</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureAcquisitions</Role>
      <ShortName>Acquisitions</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>15</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R16.htm</HtmlFileName>
      <LongName>10801 - Disclosure - Goodwill and Intangible Assets</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureGoodwillAndIntangibleAssets</Role>
      <ShortName>Goodwill and Intangible Assets</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>16</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R17.htm</HtmlFileName>
      <LongName>10901 - Disclosure - Fair Value of Financial Instruments</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureFairValueOfFinancialInstruments</Role>
      <ShortName>Fair Value of Financial Instruments</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>17</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R18.htm</HtmlFileName>
      <LongName>11001 - Disclosure - Revolving Credit Facility and Long Term Debt</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureRevolvingCreditFacilityAndLongTermDebt</Role>
      <ShortName>Revolving Credit Facility and Long Term Debt</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>18</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R19.htm</HtmlFileName>
      <LongName>11101 - Disclosure - Operating Lease Obligations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureOperatingLeaseObligations</Role>
      <ShortName>Operating Lease Obligations</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>19</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R20.htm</HtmlFileName>
      <LongName>11201 - Disclosure - Income Taxes</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureIncomeTaxes</Role>
      <ShortName>Income Taxes</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>20</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R21.htm</HtmlFileName>
      <LongName>11301 - Disclosure - Earnings Per Share</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEarningsPerShare</Role>
      <ShortName>Earnings Per Share</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>21</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R22.htm</HtmlFileName>
      <LongName>11401 - Disclosure - Restructuring and Related Charges</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureRestructuringAndRelatedCharges</Role>
      <ShortName>Restructuring and Related Charges</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>22</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R23.htm</HtmlFileName>
      <LongName>11501 - Disclosure - Employee Benefit Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlans</Role>
      <ShortName>Employee Benefit Plans</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>23</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R24.htm</HtmlFileName>
      <LongName>11601 - Disclosure - Employee Retirement Plans</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlans</Role>
      <ShortName>Employee Retirement Plans</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>24</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R25.htm</HtmlFileName>
      <LongName>11701 - Disclosure - Segment Information</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSegmentInformation</Role>
      <ShortName>Segment Information</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>25</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R26.htm</HtmlFileName>
      <LongName>11801 - Disclosure - Discontinued Operations</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureDiscontinuedOperations</Role>
      <ShortName>Discontinued Operations</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>26</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R27.htm</HtmlFileName>
      <LongName>11901 - Disclosure - Commitments and Contingencies</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureCommitmentsAndContingencies</Role>
      <ShortName>Commitments and Contingencies</ShortName>
      <MenuCategory>Notes</MenuCategory>
      <Position>27</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R28.htm</HtmlFileName>
      <LongName>20102 - Disclosure - Summary of Business and Significant Accounting Policies (Policies)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSummaryOfBusinessAndSignificantAccountingPoliciesPolicies</Role>
      <ShortName>Summary of Business and Significant Accounting Policies (Policies)</ShortName>
      <MenuCategory>Policies</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosureSummaryOfBusinessAndSignificantAccountingPolicies</ParentRole>
      <Position>28</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R29.htm</HtmlFileName>
      <LongName>30103 - Disclosure - Summary of Business and Significant Accounting Policies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSummaryOfBusinessAndSignificantAccountingPoliciesTables</Role>
      <ShortName>Summary of Business and Significant Accounting Policies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosureSummaryOfBusinessAndSignificantAccountingPolicies</ParentRole>
      <Position>29</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R30.htm</HtmlFileName>
      <LongName>30403 - Disclosure - Variable Interest Entities and Equity Method Investments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureVariableInterestEntitiesAndEquityMethodInvestmentsTables</Role>
      <ShortName>Variable Interest Entities and Equity Method Investments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosureVariableInterestEntitiesAndEquityMethodInvestments</ParentRole>
      <Position>30</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R31.htm</HtmlFileName>
      <LongName>30503 - Disclosure - Property, Plant and Equipment (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosurePropertyPlantAndEquipmentTables</Role>
      <ShortName>Property, Plant and Equipment (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosurePropertyPlantAndEquipment</ParentRole>
      <Position>31</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R32.htm</HtmlFileName>
      <LongName>30603 - Disclosure - Receivables (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureReceivablesTables</Role>
      <ShortName>Receivables (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosureReceivables</ParentRole>
      <Position>32</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R33.htm</HtmlFileName>
      <LongName>30803 - Disclosure - Goodwill and Intangible Assets (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureGoodwillAndIntangibleAssetsTables</Role>
      <ShortName>Goodwill and Intangible Assets (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosureGoodwillAndIntangibleAssets</ParentRole>
      <Position>33</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R34.htm</HtmlFileName>
      <LongName>30903 - Disclosure - Fair Value of Financial Instruments (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureFairValueOfFinancialInstrumentsTables</Role>
      <ShortName>Fair Value of Financial Instruments (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosureFairValueOfFinancialInstruments</ParentRole>
      <Position>34</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R35.htm</HtmlFileName>
      <LongName>31003 - Disclosure - Revolving Credit Facility and Long Term Debt (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureRevolvingCreditFacilityAndLongTermDebtTables</Role>
      <ShortName>Revolving Credit Facility and Long Term Debt (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosureRevolvingCreditFacilityAndLongTermDebt</ParentRole>
      <Position>35</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R36.htm</HtmlFileName>
      <LongName>31103 - Disclosure - Operating Lease Obligations (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureOperatingLeaseObligationsTables</Role>
      <ShortName>Operating Lease Obligations (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosureOperatingLeaseObligations</ParentRole>
      <Position>36</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R37.htm</HtmlFileName>
      <LongName>31203 - Disclosure - Income Taxes (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureIncomeTaxesTables</Role>
      <ShortName>Income Taxes (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosureIncomeTaxes</ParentRole>
      <Position>37</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R38.htm</HtmlFileName>
      <LongName>31303 - Disclosure - Earnings Per Share (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEarningsPerShareTables</Role>
      <ShortName>Earnings Per Share (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosureEarningsPerShare</ParentRole>
      <Position>38</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R39.htm</HtmlFileName>
      <LongName>31403 - Disclosure - Restructuring and Related Charges (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureRestructuringAndRelatedChargesTables</Role>
      <ShortName>Restructuring and Related Charges (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosureRestructuringAndRelatedCharges</ParentRole>
      <Position>39</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R40.htm</HtmlFileName>
      <LongName>31503 - Disclosure - Employee Benefit Plans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlansTables</Role>
      <ShortName>Employee Benefit Plans (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlans</ParentRole>
      <Position>40</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R41.htm</HtmlFileName>
      <LongName>31603 - Disclosure - Employee Retirement Plans (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlansTables</Role>
      <ShortName>Employee Retirement Plans (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlans</ParentRole>
      <Position>41</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R42.htm</HtmlFileName>
      <LongName>31703 - Disclosure - Segment Information (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSegmentInformationTables</Role>
      <ShortName>Segment Information (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosureSegmentInformation</ParentRole>
      <Position>42</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R43.htm</HtmlFileName>
      <LongName>31803 - Disclosure - Discontinued Operations (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureDiscontinuedOperationsTables</Role>
      <ShortName>Discontinued Operations (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosureDiscontinuedOperations</ParentRole>
      <Position>43</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R44.htm</HtmlFileName>
      <LongName>31903 - Disclosure - Commitments and Contingencies (Tables)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureCommitmentsAndContingenciesTables</Role>
      <ShortName>Commitments and Contingencies (Tables)</ShortName>
      <MenuCategory>Tables</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosureCommitmentsAndContingencies</ParentRole>
      <Position>44</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R45.htm</HtmlFileName>
      <LongName>40101 - Disclosure - Summary of Business and Significant Accounting Policies - Capital Structure (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSummaryOfBusinessAndSignificantAccountingPoliciesCapitalStructureDetails</Role>
      <ShortName>Summary of Business and Significant Accounting Policies - Capital Structure (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>45</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R46.htm</HtmlFileName>
      <LongName>40102 - Disclosure - Summary of Business and Significant Accounting Policies - Change in Fiscal Year End (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSummaryOfBusinessAndSignificantAccountingPoliciesChangeInFiscalYearEndDetails</Role>
      <ShortName>Summary of Business and Significant Accounting Policies - Change in Fiscal Year End (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>46</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R47.htm</HtmlFileName>
      <LongName>40103 - Disclosure - Summary of Business and Significant Accounting Policies - Revenue Recognition (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSummaryOfBusinessAndSignificantAccountingPoliciesRevenueRecognitionDetails</Role>
      <ShortName>Summary of Business and Significant Accounting Policies - Revenue Recognition (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>47</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R48.htm</HtmlFileName>
      <LongName>40104 - Disclosure - Summary of Business and Significant Accounting Policies - Cash and Cash Equivalents (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSummaryOfBusinessAndSignificantAccountingPoliciesCashAndCashEquivalentsDetails</Role>
      <ShortName>Summary of Business and Significant Accounting Policies - Cash and Cash Equivalents (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>48</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R49.htm</HtmlFileName>
      <LongName>40105 - Disclosure - Summary of Business and Significant Accounting Policies - General Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSummaryOfBusinessAndSignificantAccountingPoliciesGeneralInformationDetails</Role>
      <ShortName>Summary of Business and Significant Accounting Policies - General Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>49</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R50.htm</HtmlFileName>
      <LongName>40106 - Disclosure - Summary of Business and Significant Accounting Policies - Accumulated Other Comprehensive Loss - Roll Forward (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSummaryOfBusinessAndSignificantAccountingPoliciesAccumulatedOtherComprehensiveLossRollForwardDetails</Role>
      <ShortName>Summary of Business and Significant Accounting Policies - Accumulated Other Comprehensive Loss - Roll Forward (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>50</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R51.htm</HtmlFileName>
      <LongName>40107 - Disclosure - Summary of Business and Significant Accounting Policies - Accumulated Other Comprehensive Loss - Reclassifications (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSummaryOfBusinessAndSignificantAccountingPoliciesAccumulatedOtherComprehensiveLossReclassificationsDetails</Role>
      <ShortName>Summary of Business and Significant Accounting Policies - Accumulated Other Comprehensive Loss - Reclassifications (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>51</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R52.htm</HtmlFileName>
      <LongName>40108 - Disclosure - Summary of Business and Significant Accounting Policies - Recent Accounting Standards - ASU 2016-15 (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSummaryOfBusinessAndSignificantAccountingPoliciesRecentAccountingStandardsAsu201615Details</Role>
      <ShortName>Summary of Business and Significant Accounting Policies - Recent Accounting Standards - ASU 2016-15 (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>52</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R53.htm</HtmlFileName>
      <LongName>40109 - Disclosure - Summary of Business and Significant Accounting Policies - Recent Accounting Standards - ASU 2016-09 (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSummaryOfBusinessAndSignificantAccountingPoliciesRecentAccountingStandardsAsu201609Details</Role>
      <ShortName>Summary of Business and Significant Accounting Policies - Recent Accounting Standards - ASU 2016-09 (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>53</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R54.htm</HtmlFileName>
      <LongName>40110 - Disclosure - Summary of Business and Significant Accounting Policies - Recent Accounting Standards - ASU 2016-02 (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSummaryOfBusinessAndSignificantAccountingPoliciesRecentAccountingStandardsAsu201602Details</Role>
      <ShortName>Summary of Business and Significant Accounting Policies - Recent Accounting Standards - ASU 2016-02 (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>54</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R55.htm</HtmlFileName>
      <LongName>40111 - Disclosure - Summary of Business and Significant Accounting Policies - Recent Accounting Standards - ASU 2016-01 (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSummaryOfBusinessAndSignificantAccountingPoliciesRecentAccountingStandardsAsu201601Details</Role>
      <ShortName>Summary of Business and Significant Accounting Policies - Recent Accounting Standards - ASU 2016-01 (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>55</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R56.htm</HtmlFileName>
      <LongName>40112 - Disclosure - Summary of Business and Significant Accounting Policies - Recent Accounting Standards - ASU 2015-17 (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSummaryOfBusinessAndSignificantAccountingPoliciesRecentAccountingStandardsAsu201517Details</Role>
      <ShortName>Summary of Business and Significant Accounting Policies - Recent Accounting Standards - ASU 2015-17 (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>56</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R57.htm</HtmlFileName>
      <LongName>40201 - Disclosure - Changes in Project-Related Estimates (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureChangesInProjectRelatedEstimatesDetails</Role>
      <ShortName>Changes in Project-Related Estimates (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosureChangesInProjectRelatedEstimates</ParentRole>
      <Position>57</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R58.htm</HtmlFileName>
      <LongName>40301 - Disclosure - Preferred Stock Issuance (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosurePreferredStockIssuanceDetails</Role>
      <ShortName>Preferred Stock Issuance (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <ParentRole>http://www.ch2m.com/role/DisclosurePreferredStockIssuance</ParentRole>
      <Position>58</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R59.htm</HtmlFileName>
      <LongName>40401 - Disclosure - Variable Interest Entities and Equity Method Investments - General Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureVariableInterestEntitiesAndEquityMethodInvestmentsGeneralInformationDetails</Role>
      <ShortName>Variable Interest Entities and Equity Method Investments - General Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>59</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R60.htm</HtmlFileName>
      <LongName>40402 - Disclosure - Variable Interest Entities and Equity Method Investments - Summarized Financials (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureVariableInterestEntitiesAndEquityMethodInvestmentsSummarizedFinancialsDetails</Role>
      <ShortName>Variable Interest Entities and Equity Method Investments - Summarized Financials (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>60</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R61.htm</HtmlFileName>
      <LongName>40403 - Disclosure - Variable Interest Entities and Equity Method Investments - Percent Ownership (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureVariableInterestEntitiesAndEquityMethodInvestmentsPercentOwnershipDetails</Role>
      <ShortName>Variable Interest Entities and Equity Method Investments - Percent Ownership (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>61</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R62.htm</HtmlFileName>
      <LongName>40501 - Disclosure - Property, Plant and Equipment - Tabular Disclosure (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosurePropertyPlantAndEquipmentTabularDisclosureDetails</Role>
      <ShortName>Property, Plant and Equipment - Tabular Disclosure (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>62</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R63.htm</HtmlFileName>
      <LongName>40502 - Disclosure - Property, Plant and Equipment - Depreciation Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosurePropertyPlantAndEquipmentDepreciationExpenseDetails</Role>
      <ShortName>Property, Plant and Equipment - Depreciation Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>63</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R64.htm</HtmlFileName>
      <LongName>40503 - Disclosure - Property, Plant and Equipment - Additions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosurePropertyPlantAndEquipmentAdditionsDetails</Role>
      <ShortName>Property, Plant and Equipment - Additions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>64</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R65.htm</HtmlFileName>
      <LongName>40601 - Disclosure - Receivables - General Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureReceivablesGeneralInformationDetails</Role>
      <ShortName>Receivables - General Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>65</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R66.htm</HtmlFileName>
      <LongName>40602 - Disclosure - Receivables - Allowance for Uncollectible Accounts (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureReceivablesAllowanceForUncollectibleAccountsDetails</Role>
      <ShortName>Receivables - Allowance for Uncollectible Accounts (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>66</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R67.htm</HtmlFileName>
      <LongName>40701 - Disclosure - Acquisitions - TERA Acquisition - Consideration (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureAcquisitionsTeraAcquisitionConsiderationDetails</Role>
      <ShortName>Acquisitions - TERA Acquisition - Consideration (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>67</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R68.htm</HtmlFileName>
      <LongName>40702 - Disclosure - Acquisitions - TERA Acquisition - Pro Forma Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureAcquisitionsTeraAcquisitionProFormaInformationDetails</Role>
      <ShortName>Acquisitions - TERA Acquisition - Pro Forma Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>68</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R69.htm</HtmlFileName>
      <LongName>40703 - Disclosure - Acquisitions - Controlling Interest in Joint Venture (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureAcquisitionsControllingInterestInJointVentureDetails</Role>
      <ShortName>Acquisitions - Controlling Interest in Joint Venture (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>69</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R70.htm</HtmlFileName>
      <LongName>40801 - Disclosure - Goodwill and Intangible Assets - Goodwill Impairment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureGoodwillAndIntangibleAssetsGoodwillImpairmentDetails</Role>
      <ShortName>Goodwill and Intangible Assets - Goodwill Impairment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>70</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R71.htm</HtmlFileName>
      <LongName>40802 - Disclosure - Goodwill and Intangible Assets - Finite-lived Intangible Asset Impairment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureGoodwillAndIntangibleAssetsFiniteLivedIntangibleAssetImpairmentDetails</Role>
      <ShortName>Goodwill and Intangible Assets - Finite-lived Intangible Asset Impairment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>71</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R72.htm</HtmlFileName>
      <LongName>40803 - Disclosure - Goodwill and Intangible Assets - Goodwill by Segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureGoodwillAndIntangibleAssetsGoodwillBySegmentDetails</Role>
      <ShortName>Goodwill and Intangible Assets - Goodwill by Segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>72</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R73.htm</HtmlFileName>
      <LongName>40804 - Disclosure - Goodwill and Intangible Assets - Intangible Assets by Segment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureGoodwillAndIntangibleAssetsIntangibleAssetsBySegmentDetails</Role>
      <ShortName>Goodwill and Intangible Assets - Intangible Assets by Segment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>73</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R74.htm</HtmlFileName>
      <LongName>40805 - Disclosure - Goodwill and Intangible Assets - Intangible Assets with Finite Lives (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureGoodwillAndIntangibleAssetsIntangibleAssetsWithFiniteLivesDetails</Role>
      <ShortName>Goodwill and Intangible Assets - Intangible Assets with Finite Lives (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>74</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R75.htm</HtmlFileName>
      <LongName>40806 - Disclosure - Goodwill and Intangible Assets - Expected Lives (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureGoodwillAndIntangibleAssetsExpectedLivesDetails</Role>
      <ShortName>Goodwill and Intangible Assets - Expected Lives (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>75</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R76.htm</HtmlFileName>
      <LongName>40807 - Disclosure - Goodwill and Intangible Assets - Amortization Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureGoodwillAndIntangibleAssetsAmortizationExpenseDetails</Role>
      <ShortName>Goodwill and Intangible Assets - Amortization Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>76</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R77.htm</HtmlFileName>
      <LongName>40808 - Disclosure - Goodwill and Intangible Assets - Future Estimated Amortization Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureGoodwillAndIntangibleAssetsFutureEstimatedAmortizationExpenseDetails</Role>
      <ShortName>Goodwill and Intangible Assets - Future Estimated Amortization Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>77</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R78.htm</HtmlFileName>
      <LongName>40901 - Disclosure - Fair Value of Financial Instruments - General Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureFairValueOfFinancialInstrumentsGeneralInformationDetails</Role>
      <ShortName>Fair Value of Financial Instruments - General Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>78</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R79.htm</HtmlFileName>
      <LongName>40902 - Disclosure - Fair Value of Financial Instruments - Foreign Exchange Contracts (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureFairValueOfFinancialInstrumentsForeignExchangeContractsDetails</Role>
      <ShortName>Fair Value of Financial Instruments - Foreign Exchange Contracts (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>79</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R80.htm</HtmlFileName>
      <LongName>41001 - Disclosure - Revolving Credit Facility and Long Term Debt - General Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureRevolvingCreditFacilityAndLongTermDebtGeneralInformationDetails</Role>
      <ShortName>Revolving Credit Facility and Long Term Debt - General Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>80</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R81.htm</HtmlFileName>
      <LongName>41002 - Disclosure - Revolving Credit Facility and Long-Term Debt - Future Payments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureRevolvingCreditFacilityAndLongTermDebtFuturePaymentsDetails</Role>
      <ShortName>Revolving Credit Facility and Long-Term Debt - Future Payments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>81</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R82.htm</HtmlFileName>
      <LongName>41101 - Disclosure - Operating Lease Obligations - Future Minimum Lease Payments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureOperatingLeaseObligationsFutureMinimumLeasePaymentsDetails</Role>
      <ShortName>Operating Lease Obligations - Future Minimum Lease Payments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>82</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R83.htm</HtmlFileName>
      <LongName>41102 - Disclosure - Operating Lease Obligations - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureOperatingLeaseObligationsAdditionalInformationDetails</Role>
      <ShortName>Operating Lease Obligations - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>83</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R84.htm</HtmlFileName>
      <LongName>41201 - Disclosure - Income Taxes Summary - Income before Provision for Income Taxes - Domestic and Foreign (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureIncomeTaxesSummaryIncomeBeforeProvisionForIncomeTaxesDomesticAndForeignDetails</Role>
      <ShortName>Income Taxes Summary - Income before Provision for Income Taxes - Domestic and Foreign (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>84</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R85.htm</HtmlFileName>
      <LongName>41202 - Disclosure - Income Taxes Summary - Income before Provision for Income Taxes - Current and Deferred (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureIncomeTaxesSummaryIncomeBeforeProvisionForIncomeTaxesCurrentAndDeferredDetails</Role>
      <ShortName>Income Taxes Summary - Income before Provision for Income Taxes - Current and Deferred (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>85</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R86.htm</HtmlFileName>
      <LongName>41203 - Disclosure - Income Taxes Summary - Reconciliations of Income Tax (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureIncomeTaxesSummaryReconciliationsOfIncomeTaxDetails</Role>
      <ShortName>Income Taxes Summary - Reconciliations of Income Tax (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>86</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R87.htm</HtmlFileName>
      <LongName>41204 - Disclosure - Income Taxes Summary - Deferred Tax Assets and Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureIncomeTaxesSummaryDeferredTaxAssetsAndLiabilitiesDetails</Role>
      <ShortName>Income Taxes Summary - Deferred Tax Assets and Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>87</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R88.htm</HtmlFileName>
      <LongName>41205 - Disclosure - Income Taxes Summary - Effective Tax Rate (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureIncomeTaxesSummaryEffectiveTaxRateDetails</Role>
      <ShortName>Income Taxes Summary - Effective Tax Rate (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>88</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R89.htm</HtmlFileName>
      <LongName>41206 - Disclosure - Income Taxes Summary - Valuation Allowance (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureIncomeTaxesSummaryValuationAllowanceDetails</Role>
      <ShortName>Income Taxes Summary - Valuation Allowance (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>89</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R90.htm</HtmlFileName>
      <LongName>41207 - Disclosure - Income Taxes Summary - Net Operating Loss Carryforward (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureIncomeTaxesSummaryNetOperatingLossCarryforwardDetails</Role>
      <ShortName>Income Taxes Summary - Net Operating Loss Carryforward (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>90</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R91.htm</HtmlFileName>
      <LongName>41208 - Disclosure - Income Taxes Summary - Tax Credit Carryforward (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureIncomeTaxesSummaryTaxCreditCarryforwardDetails</Role>
      <ShortName>Income Taxes Summary - Tax Credit Carryforward (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>91</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R92.htm</HtmlFileName>
      <LongName>41209 - Disclosure - Income Taxes Summary - HGL Deferred Tax Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureIncomeTaxesSummaryHglDeferredTaxAssetsDetails</Role>
      <ShortName>Income Taxes Summary - HGL Deferred Tax Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>92</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R93.htm</HtmlFileName>
      <LongName>41210 - Disclosure - Income Taxes Summary - ASU 2016-09 (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureIncomeTaxesSummaryAsu201609Details</Role>
      <ShortName>Income Taxes Summary - ASU 2016-09 (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>93</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R94.htm</HtmlFileName>
      <LongName>41211 - Disclosure - Income Taxes Summary - Undistributed Foreign Earnings (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureIncomeTaxesSummaryUndistributedForeignEarningsDetails</Role>
      <ShortName>Income Taxes Summary - Undistributed Foreign Earnings (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>94</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R95.htm</HtmlFileName>
      <LongName>41212 - Disclosure - Income Taxes Summary - Uncertain Tax Positions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureIncomeTaxesSummaryUncertainTaxPositionsDetails</Role>
      <ShortName>Income Taxes Summary - Uncertain Tax Positions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>95</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R96.htm</HtmlFileName>
      <LongName>41213 - Disclosure - Income Taxes Summary - Reconciliation of Uncertain Tax Positions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureIncomeTaxesSummaryReconciliationOfUncertainTaxPositionsDetails</Role>
      <ShortName>Income Taxes Summary - Reconciliation of Uncertain Tax Positions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>96</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R97.htm</HtmlFileName>
      <LongName>41214 - Disclosure - Income Taxes Summary - Uncertain Tax Positions Affecting the Effective Tax Rate (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureIncomeTaxesSummaryUncertainTaxPositionsAffectingEffectiveTaxRateDetails</Role>
      <ShortName>Income Taxes Summary - Uncertain Tax Positions Affecting the Effective Tax Rate (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>97</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R98.htm</HtmlFileName>
      <LongName>41301 - Disclosure - Earnings Per Share - General Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEarningsPerShareGeneralInformationDetails</Role>
      <ShortName>Earnings Per Share - General Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>98</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R99.htm</HtmlFileName>
      <LongName>41302 - Disclosure - Earnings Per Share - Reconciliations of Basic and Diluted EPS (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEarningsPerShareReconciliationsOfBasicAndDilutedEpsDetails</Role>
      <ShortName>Earnings Per Share - Reconciliations of Basic and Diluted EPS (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>99</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R100.htm</HtmlFileName>
      <LongName>41303 - Disclosure - Earnings Per Share - Antidilutive Securities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEarningsPerShareAntidilutiveSecuritiesDetails</Role>
      <ShortName>Earnings Per Share - Antidilutive Securities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>100</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R101.htm</HtmlFileName>
      <LongName>41401 - Disclosure - Restructuring and Related Charges - General Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureRestructuringAndRelatedChargesGeneralInformationDetails</Role>
      <ShortName>Restructuring and Related Charges - General Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>101</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R102.htm</HtmlFileName>
      <LongName>41402 - Disclosure - Restructuring and Related Charges - Changes in the Provision for Restructuring Activities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureRestructuringAndRelatedChargesChangesInProvisionForRestructuringActivitiesDetails</Role>
      <ShortName>Restructuring and Related Charges - Changes in the Provision for Restructuring Activities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>102</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R103.htm</HtmlFileName>
      <LongName>41501 - Disclosure - Employee Benefit Plans - Deferred Compensation Plans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlansDeferredCompensationPlansDetails</Role>
      <ShortName>Employee Benefit Plans - Deferred Compensation Plans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>103</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R104.htm</HtmlFileName>
      <LongName>41502 - Disclosure - Employee Benefit Plans - Stock Options - General Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlansStockOptionsGeneralInformationDetails</Role>
      <ShortName>Employee Benefit Plans - Stock Options - General Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>104</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R105.htm</HtmlFileName>
      <LongName>41503 - Disclosure - Employee Benefit Plans - Stock Options - Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlansStockOptionsActivityDetails</Role>
      <ShortName>Employee Benefit Plans - Stock Options - Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>105</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R106.htm</HtmlFileName>
      <LongName>41504 - Disclosure - Employee Benefit Plans - Stock Options - Summary of Stock Options Outstanding and Stock Options Vested and Exercisable (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlansStockOptionsSummaryOfStockOptionsOutstandingAndStockOptionsVestedAndExercisableDetails</Role>
      <ShortName>Employee Benefit Plans - Stock Options - Summary of Stock Options Outstanding and Stock Options Vested and Exercisable (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>106</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R107.htm</HtmlFileName>
      <LongName>41505 - Disclosure - Employee Benefit Plans - Stock Options - Additional Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlansStockOptionsAdditionalInformationDetails</Role>
      <ShortName>Employee Benefit Plans - Stock Options - Additional Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>107</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R108.htm</HtmlFileName>
      <LongName>41506 - Disclosure - Employee Benefit Plans - Stock Options - Assumptions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlansStockOptionsAssumptionsDetails</Role>
      <ShortName>Employee Benefit Plans - Stock Options - Assumptions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>108</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R109.htm</HtmlFileName>
      <LongName>41507 - Disclosure - Employee Benefit Plans - Stock Options - Compensation Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlansStockOptionsCompensationExpenseDetails</Role>
      <ShortName>Employee Benefit Plans - Stock Options - Compensation Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>109</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R110.htm</HtmlFileName>
      <LongName>41508 - Disclosure - Employee Benefit Plans - Payroll Deduction Stock Purchase Plan (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlansPayrollDeductionStockPurchasePlanDetails</Role>
      <ShortName>Employee Benefit Plans - Payroll Deduction Stock Purchase Plan (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>110</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R111.htm</HtmlFileName>
      <LongName>41509 - Disclosure - Employee Benefit Plans - Phantom Stock Plan - General Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlansPhantomStockPlanGeneralInformationDetails</Role>
      <ShortName>Employee Benefit Plans - Phantom Stock Plan - General Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>111</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R112.htm</HtmlFileName>
      <LongName>41510 - Disclosure - Employee Benefit Plans - Phantom Stock Plan - Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlansPhantomStockPlanActivityDetails</Role>
      <ShortName>Employee Benefit Plans - Phantom Stock Plan - Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>112</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R113.htm</HtmlFileName>
      <LongName>41511 - Disclosure - Employee Benefit Plans - Stock Appreciation Rights Plan - General Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlansStockAppreciationRightsPlanGeneralInformationDetails</Role>
      <ShortName>Employee Benefit Plans - Stock Appreciation Rights Plan - General Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>113</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R114.htm</HtmlFileName>
      <LongName>41512 - Disclosure - Employee Benefit Plans - Stock Appreciation Rights Plan - Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlansStockAppreciationRightsPlanActivityDetails</Role>
      <ShortName>Employee Benefit Plans - Stock Appreciation Rights Plan - Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>114</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R115.htm</HtmlFileName>
      <LongName>41513 - Disclosure - Employee Benefit Plans - Long Term Incentive Plan (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlansLongTermIncentivePlanDetails</Role>
      <ShortName>Employee Benefit Plans - Long Term Incentive Plan (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>115</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R116.htm</HtmlFileName>
      <LongName>41514 - Disclosure - Employee Benefit Plans - Restricted Stock Plan - General Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlansRestrictedStockPlanGeneralInformationDetails</Role>
      <ShortName>Employee Benefit Plans - Restricted Stock Plan - General Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>116</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R117.htm</HtmlFileName>
      <LongName>41515 - Disclosure - Employee Benefit Plans - Restricted Stock Plan - Activity (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlansRestrictedStockPlanActivityDetails</Role>
      <ShortName>Employee Benefit Plans - Restricted Stock Plan - Activity (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>117</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R118.htm</HtmlFileName>
      <LongName>41516 - Disclosure - Employee Benefit Plans - Restricted Stock Plan - Weighted-average Fair Values (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeBenefitPlansRestrictedStockPlanWeightedAverageFairValuesDetails</Role>
      <ShortName>Employee Benefit Plans - Restricted Stock Plan - Weighted-average Fair Values (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>118</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R119.htm</HtmlFileName>
      <LongName>41601 - Disclosure - Employee Retirement Plans - Retirement and Tax Deferred Savings Plan (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlansRetirementAndTaxDeferredSavingsPlanDetails</Role>
      <ShortName>Employee Retirement Plans - Retirement and Tax Deferred Savings Plan (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>119</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R120.htm</HtmlFileName>
      <LongName>41602 - Disclosure - Employee Retirement Plans - Defined Benefit Plans - Number of Plans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlansDefinedBenefitPlansNumberOfPlansDetails</Role>
      <ShortName>Employee Retirement Plans - Defined Benefit Plans - Number of Plans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>120</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R121.htm</HtmlFileName>
      <LongName>41603 - Disclosure - Employee Retirement Plans - Defined Benefit Plans - Change in Defined Benefit Plans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlansDefinedBenefitPlansChangeInDefinedBenefitPlansDetails</Role>
      <ShortName>Employee Retirement Plans - Defined Benefit Plans - Change in Defined Benefit Plans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>121</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R122.htm</HtmlFileName>
      <LongName>41604 - Disclosure - Employee Retirement Plans - Defined Benefit Plans - Measurement Date (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlansDefinedBenefitPlansMeasurementDateDetails</Role>
      <ShortName>Employee Retirement Plans - Defined Benefit Plans - Measurement Date (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>122</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R123.htm</HtmlFileName>
      <LongName>41605 - Disclosure - Employee Retirement Plans - Benefit Expense - Actuarial Assumptions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlansBenefitExpenseActuarialAssumptionsDetails</Role>
      <ShortName>Employee Retirement Plans - Benefit Expense - Actuarial Assumptions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>123</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R124.htm</HtmlFileName>
      <LongName>41606 - Disclosure - Employee Retirement Plans - Components of Pension Benefit Expense (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlansComponentsOfPensionBenefitExpenseDetails</Role>
      <ShortName>Employee Retirement Plans - Components of Pension Benefit Expense (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>124</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R125.htm</HtmlFileName>
      <LongName>41607 - Disclosure - Employee Retirement Plans - Benefit Obligations - Assumptions (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlansBenefitObligationsAssumptionsDetails</Role>
      <ShortName>Employee Retirement Plans - Benefit Obligations - Assumptions (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>125</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R126.htm</HtmlFileName>
      <LongName>41608 - Disclosure - Employee Retirement Plans - Change in Benefit Obligations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlansChangeInBenefitObligationsDetails</Role>
      <ShortName>Employee Retirement Plans - Change in Benefit Obligations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>126</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R127.htm</HtmlFileName>
      <LongName>41609 - Disclosure - Employee Retirement Plans - Change in Plan Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlansChangeInPlanAssetsDetails</Role>
      <ShortName>Employee Retirement Plans - Change in Plan Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>127</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R128.htm</HtmlFileName>
      <LongName>41610 - Disclosure - Employee Retirement Plans - Projected Benefit Obligation and Funding (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlansProjectedBenefitObligationAndFundingDetails</Role>
      <ShortName>Employee Retirement Plans - Projected Benefit Obligation and Funding (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>128</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R129.htm</HtmlFileName>
      <LongName>41611 - Disclosure - Employee Retirement Plans - Expected Benefit Payments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlansExpectedBenefitPaymentsDetails</Role>
      <ShortName>Employee Retirement Plans - Expected Benefit Payments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>129</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R130.htm</HtmlFileName>
      <LongName>41612 - Disclosure - Employee Retirement Plans - Benefit Plan Assets (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlansBenefitPlanAssetsDetails</Role>
      <ShortName>Employee Retirement Plans - Benefit Plan Assets (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>130</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R131.htm</HtmlFileName>
      <LongName>41613 - Disclosure - Employee Retirement Plans - Total Investments Fair Value (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlansTotalInvestmentsFairValueDetails</Role>
      <ShortName>Employee Retirement Plans - Total Investments Fair Value (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>131</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R132.htm</HtmlFileName>
      <LongName>41614 - Disclosure - Employee Retirement Plans - Defined Benefit Plans - Funded Status (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlansDefinedBenefitPlansFundedStatusDetails</Role>
      <ShortName>Employee Retirement Plans - Defined Benefit Plans - Funded Status (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>132</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R133.htm</HtmlFileName>
      <LongName>41615 - Disclosure - Employee Retirement Plans - Other Postretirement Benefits (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlansOtherPostretirementBenefitsDetails</Role>
      <ShortName>Employee Retirement Plans - Other Postretirement Benefits (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>133</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R134.htm</HtmlFileName>
      <LongName>41616 - Disclosure - Employee Retirement Plans - Other Postretirement Benefits - Funded Status (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlansOtherPostretirementBenefitsFundedStatusDetails</Role>
      <ShortName>Employee Retirement Plans - Other Postretirement Benefits - Funded Status (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>134</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R135.htm</HtmlFileName>
      <LongName>41617 - Disclosure - Employee Retirement Plans - Multiemployer Plans (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureEmployeeRetirementPlansMultiemployerPlansDetails</Role>
      <ShortName>Employee Retirement Plans - Multiemployer Plans (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>135</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R136.htm</HtmlFileName>
      <LongName>41701 - Disclosure - Segment Information - Adjustment to Revenue and Direct Cost of Services (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSegmentInformationAdjustmentToRevenueAndDirectCostOfServicesDetails</Role>
      <ShortName>Segment Information - Adjustment to Revenue and Direct Cost of Services (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>136</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R137.htm</HtmlFileName>
      <LongName>41702 - Disclosure - Segment Information - Certain Financial Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSegmentInformationCertainFinancialInformationDetails</Role>
      <ShortName>Segment Information - Certain Financial Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>137</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R138.htm</HtmlFileName>
      <LongName>41703 - Disclosure - Segment Information - Significant Clients (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSegmentInformationSignificantClientsDetails</Role>
      <ShortName>Segment Information - Significant Clients (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>138</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R139.htm</HtmlFileName>
      <LongName>41704 - Disclosure - Segment Information - Operating Information by Geographic Area (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSegmentInformationOperatingInformationByGeographicAreaDetails</Role>
      <ShortName>Segment Information - Operating Information by Geographic Area (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>139</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R140.htm</HtmlFileName>
      <LongName>41705 - Disclosure - Segment Information - U.S. and International Revenue (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSegmentInformationUsAndInternationalRevenueDetails</Role>
      <ShortName>Segment Information - U.S. and International Revenue (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>140</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R141.htm</HtmlFileName>
      <LongName>41706 - Disclosure - Segment Information - Net Property, Plant and Equipment (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureSegmentInformationNetPropertyPlantAndEquipmentDetails</Role>
      <ShortName>Segment Information - Net Property, Plant and Equipment (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>141</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R142.htm</HtmlFileName>
      <LongName>41801 - Disclosure - Discontinued Operations - General Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureDiscontinuedOperationsGeneralInformationDetails</Role>
      <ShortName>Discontinued Operations - General Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>142</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R143.htm</HtmlFileName>
      <LongName>41802 - Disclosure - Discontinued Operations - Reconciliation of Net Income (Loss) from Discontinued Operations (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureDiscontinuedOperationsReconciliationOfNetIncomeLossFromDiscontinuedOperationsDetails</Role>
      <ShortName>Discontinued Operations - Reconciliation of Net Income (Loss) from Discontinued Operations (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>143</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R144.htm</HtmlFileName>
      <LongName>41803 - Disclosure - Discontinued Operations - Reconciliation of Carrying Amounts of Assets and Liabilities (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureDiscontinuedOperationsReconciliationOfCarryingAmountsOfAssetsAndLiabilitiesDetails</Role>
      <ShortName>Discontinued Operations - Reconciliation of Carrying Amounts of Assets and Liabilities (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>144</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R145.htm</HtmlFileName>
      <LongName>41901 - Disclosure - Commitments and Contingencies - Commercial Commitments (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureCommitmentsAndContingenciesCommercialCommitmentsDetails</Role>
      <ShortName>Commitments and Contingencies - Commercial Commitments (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>145</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R146.htm</HtmlFileName>
      <LongName>41902 - Disclosure - Commitments and Contingencies - General Information (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureCommitmentsAndContingenciesGeneralInformationDetails</Role>
      <ShortName>Commitments and Contingencies - General Information (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>146</Position>
    </Report>
    <Report instance="chm-20170919.xml">
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <HtmlFileName>R147.htm</HtmlFileName>
      <LongName>42001 - Disclosure - Quarterly Financial Information (unaudited) (Details)</LongName>
      <ReportType>Sheet</ReportType>
      <Role>http://www.ch2m.com/role/DisclosureQuarterlyFinancialInformationUnauditedDetails</Role>
      <ShortName>Quarterly Financial Information (unaudited) (Details)</ShortName>
      <MenuCategory>Details</MenuCategory>
      <Position>147</Position>
    </Report>
    <Report>
      <IsDefault>false</IsDefault>
      <HasEmbeddedReports>false</HasEmbeddedReports>
      <LongName>All Reports</LongName>
      <ReportType>Book</ReportType>
      <ShortName>All Reports</ShortName>
    </Report>
  </MyReports>
  <InputFiles>
    <File>chm-20170919.xml</File>
    <File>chm-20170919.xsd</File>
    <File>chm-20170919_cal.xml</File>
    <File>chm-20170919_def.xml</File>
    <File>chm-20170919_lab.xml</File>
    <File>chm-20170919_pre.xml</File>
  </InputFiles>
  <SupplementalFiles/>
  <BaseTaxonomies/>
  <HasPresentationLinkbase>true</HasPresentationLinkbase>
  <HasCalculationLinkbase>true</HasCalculationLinkbase>
</FilingSummary>
