<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-05-26</periodOfReport>

    <issuer>
        <issuerCik>0001320461</issuerCik>
        <issuerName>Cooper-Standard Holdings Inc.</issuerName>
        <issuerTradingSymbol>CPS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001332784</rptOwnerCik>
            <rptOwnerName>Silver Point Capital L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>TWO GREENWICH PLAZA</rptOwnerStreet1>
            <rptOwnerStreet2>FIRST FLOOR</rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001029625</rptOwnerCik>
            <rptOwnerName>MULE EDWARD A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>TWO GREENWICH PLAZA</rptOwnerStreet1>
            <rptOwnerStreet2>FIRST FLOOR</rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001382617</rptOwnerCik>
            <rptOwnerName>O'Shea Robert J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>TWO GREENWICH PLAZA</rptOwnerStreet1>
            <rptOwnerStreet2>FIRST FLOOR</rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2017-05-26</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>10000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>112.6575</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1500413</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Silver Point Capital, L.P. (&quot;Silver Point&quot;) is the investment manager of Silver Point Capital Fund, L.P. and Silver Point Capital Offshore Fund, Ltd. (the &quot;Funds&quot;) and, by reason of such status, may be deemed to be the beneficial owner of all of the reported securities held by the Funds. Silver Point Capital Management, LLC (&quot;Management&quot;) is the general partner of Silver Point and as a result may be deemed to be the beneficial owner of all securities held by the Funds. Messrs. Edward A. Mule and Robert J. O'Shea are each members of Management and as a result may be deemed to be the beneficial owner of all of the securities held by the Funds. Silver Point, Management and Messrs. Mule and O'Shea disclaim beneficial ownership of the reported securities held by the Funds except to the extent of their pecuniary interests.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Steven Weiser, Authorized Signatory on behalf of Silver Point Capital, L.P.</signatureName>
        <signatureDate>2017-05-31</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Steven Weiser (as attorney-in-fact on behalf of Edward A Mule, individually)</signatureName>
        <signatureDate>2017-05-31</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Steven Weiser (as attorney-in-fact on behalf of Robert J. O'Shea, individually)</signatureName>
        <signatureDate>2017-05-31</signatureDate>
    </ownerSignature>
</ownershipDocument>
