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

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-05-25</periodOfReport>

    <issuer>
        <issuerCik>0000726990</issuerCik>
        <issuerName>AMERICANWEST BANCORPORATION</issuerName>
        <issuerTradingSymbol>AWBC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001299524</rptOwnerCik>
            <rptOwnerName>Griffith Wade A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O AMERICANWEST BANCORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>41 W. RIVERSIDE AVE. SUITE 400</rptOwnerStreet2>
            <rptOwnerCity>SPOKANE</rptOwnerCity>
            <rptOwnerState>WA</rptOwnerState>
            <rptOwnerZipCode>99201</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP/Chief Information Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-05-25</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>800</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>24.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5627</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3624.42</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Held by 401(k) Plan</value>
                    <footnoteId id="F1"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Effective April 25, 2006, AmericanWest Bancorporation approved the consolidation and merger of the ESOP Plan into the existing AmericanWest Bank 401 (k) Plan.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>by R. Blair Reynolds, Pursuant to Power of Attorney on File</signatureName>
        <signatureDate>2006-05-26</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0202
4
2006-05-25
0000726990
AMERICANWEST BANCORPORATION
AWBC
0001299524
Griffith Wade A
C/O AMERICANWEST BANCORPORATION
41 W. RIVERSIDE AVE. SUITE 400
SPOKANE
WA
99201
0
1
0
0
SVP/Chief Information Officer
Common Stock
2006-05-25
4
S
0
800
24.00
D
5627
D
Common Stock
3624.42
I
Held by 401(k) Plan
Effective April 25, 2006, AmericanWest Bancorporation approved the consolidation and merger of the ESOP Plan into the existing AmericanWest Bank 401 (k) Plan.
by R. Blair Reynolds, Pursuant to Power of Attorney on File
2006-05-26