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1/1/2010 - 12/31/2010
USD ($)
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1/1/2009 - 12/31/2009
USD ($)
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1/1/2008 - 12/31/2008
USD ($)
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 -Publisher FASB
 -Name Statement of Financial Accounting Standard (FAS)
 -Number 132R
 -Paragraph 5
 -Subparagraph h

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USD ($)
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1/1/2009 - 12/31/2009
USD ($)
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USD ($)
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 -Publisher FASB
 -Name Statement of Financial Accounting Standard (FAS)
 -Number 132R
 -Paragraph 5
 -Subparagraph h

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USD ($)
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1/1/2009 - 12/31/2009
USD ($)
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1/1/2008 - 12/31/2008
USD ($)
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1/1/2010 - 12/31/2010
USD ($)
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1/1/2009 - 12/31/2009
USD ($)
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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Other Benefits [Member]
1/1/2008 - 12/31/2008
USD ($)
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 -Publisher FASB
 -Name Statement of Financial Accounting Standard (FAS)
 -Number 132R
 -Paragraph 5
 -Subparagraph h

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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Pension Benefits [Member]
1/1/2010 - 12/31/2010
USD ($)
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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Pension Benefits [Member]
1/1/2009 - 12/31/2009
USD ($)
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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Pension Benefits [Member]
1/1/2008 - 12/31/2008
USD ($)
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/><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios></Cell></Cells><OriginalInstanceReportColumns /><Unit>Monetary</Unit><ElementDataType>xbrli:monetaryItemType</ElementDataType><SimpleDataType>monetary</SimpleDataType><ElementDefenition>The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain or loss, prior service cost or credit, transition asset or obligation, and gain or loss due to settlements or curtailments).</ElementDefenition><ElementReferences>Reference 1: http://www.xbrl.org/2003/role/presentationRef
 -Publisher FASB
 -Name Statement of Financial Accounting Standard (FAS)
 -Number 132R
 -Paragraph 5
 -Subparagraph h

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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Other Benefits [Member]
1/1/2010 - 12/31/2010
USD ($)
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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Other Benefits [Member]
1/1/2009 - 12/31/2009
USD ($)
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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Other Benefits [Member]
1/1/2008 - 12/31/2008
USD ($)
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 -Name Statement of Financial Accounting Standard (FAS)
 -Number 132R
 -Paragraph 5
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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Pension Benefits [Member]
1/1/2010 - 12/31/2010
USD ($)
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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Pension Benefits [Member]
1/1/2009 - 12/31/2009
USD ($)
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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Pension Benefits [Member]
1/1/2008 - 12/31/2008
USD ($)
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 -Name Statement of Financial Accounting Standard (FAS)
 -Number 132R
 -Paragraph 5
 -Subparagraph h

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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Other Benefits [Member]
1/1/2010 - 12/31/2010
USD ($)
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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Other Benefits [Member]
1/1/2009 - 12/31/2009
USD ($)
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1/1/2008 - 12/31/2008
USD ($)
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 -Publisher FASB
 -Name Statement of Financial Accounting Standard (FAS)
 -Number 132R
 -Paragraph 5
 -Subparagraph h

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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Pension Benefits [Member]
1/1/2010 - 12/31/2010
USD ($)
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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Pension Benefits [Member]
1/1/2009 - 12/31/2009
USD ($)
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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Pension Benefits [Member]
1/1/2008 - 12/31/2008
USD ($)
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/><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios></Cell></Cells><OriginalInstanceReportColumns /><Unit>Monetary</Unit><ElementDataType>xbrli:monetaryItemType</ElementDataType><SimpleDataType>monetary</SimpleDataType><ElementDefenition>The total amount of net periodic benefit cost for defined benefit plans for the period. 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 -Publisher FASB
 -Name Statement of Financial Accounting Standard (FAS)
 -Number 132R
 -Paragraph 5
 -Subparagraph h

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 -Publisher FASB
 -Name Statement of Financial Accounting Standard (FAS)
 -Number 132R
 -Paragraph 5
 -Subparagraph h

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USD ($)
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1/1/2010 - 12/31/2010
USD ($)
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1/1/2009 - 12/31/2009
USD ($)
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1/1/2008 - 12/31/2008
USD ($)
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 -Publisher FASB
 -Name Statement of Financial Accounting Standard (FAS)
 -Number 132R
 -Paragraph 5
 -Subparagraph h

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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Pension Benefits [Member]
1/1/2010 - 12/31/2010
USD ($)
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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Pension Benefits [Member]
1/1/2009 - 12/31/2009
USD ($)
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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Pension Benefits [Member]
1/1/2008 - 12/31/2008
USD ($)
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/><CurrencyCode /><CurrencySymbol /><IsIndependantCurrency>false</IsIndependantCurrency><ShowCurrencySymbol>false</ShowCurrencySymbol><DisplayDateInUSFormat>false</DisplayDateInUSFormat><hasSegments>false</hasSegments><hasScenarios>false</hasScenarios></Cell></Cells><OriginalInstanceReportColumns /><Unit>Monetary</Unit><ElementDataType>xbrli:monetaryItemType</ElementDataType><SimpleDataType>monetary</SimpleDataType><ElementDefenition>The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain or loss, prior service cost or credit, transition asset or obligation, and gain or loss due to settlements or curtailments).</ElementDefenition><ElementReferences>Reference 1: http://www.xbrl.org/2003/role/presentationRef
 -Publisher FASB
 -Name Statement of Financial Accounting Standard (FAS)
 -Number 132R
 -Paragraph 5
 -Subparagraph h

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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Other Benefits [Member]
1/1/2010 - 12/31/2010
USD ($)
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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Other Benefits [Member]
1/1/2009 - 12/31/2009
USD ($)
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{us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis} : Other Benefits [Member]
1/1/2008 - 12/31/2008
USD ($)
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1/1/2010 - 12/31/2010
USD ($)

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1/1/2009 - 12/31/2009
USD ($)

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1/1/2008 - 12/31/2008
USD ($)
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 -Number 132R
 -Paragraph 5
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1/1/2010 - 12/31/2010
USD ($)

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1/1/2009 - 12/31/2009
USD ($)

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1/1/2008 - 12/31/2008
USD ($)
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 -Publisher FASB
 -Name Statement of Financial Accounting Standard (FAS)
 -Number 132R
 -Paragraph 5
 -Subparagraph h

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