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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-01-07</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000945764</issuerCik>
        <issuerName>DENBURY RESOURCES INC</issuerName>
        <issuerTradingSymbol>DNR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001374267</rptOwnerCik>
            <rptOwnerName>Cornelius Robert L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5100 TENNYSON PARKWAY</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 1200</rptOwnerStreet2>
            <rptOwnerCity>PLANO</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75024</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Sr. V.P. Operations</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-01-07</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>12644</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>115230</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">These restricted shares will vest 100% on March 31, 2011 or upon any earlier change of control, as defined, of the issuer.  With respect to one-third of these restricted shares, delivery of the shares will not be made until the reporting person's separation from the issuer.  The restricted shares reflected in the table above do not reflect a separate simultaneous grant by the Company of performance-based restricted stock representing the right to receive up to twice the number of shares of restricted stock of the Company shown in the table above based upon levels of achievement in 2008, 2009 and 2010 of four different weighted Company operational and corporate performance targets.  Any performance-based restricted shares earned will vest on March 31, 2011, and unvested portions will be forfeited.  One-half of the performance-based restricted shares will be earned for performance at the designated target levels or upon any earlier change of control.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Phil Rykhoek - Per Confirming Statement</signatureName>
        <signatureDate>2008-01-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
