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USD ($)

USD ($) / shares

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USD ($)
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3/31/2011
USD ($)
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12/31/2010
USD ($)
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3/31/2011
USD ($)
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12/31/2010
USD ($)
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3/31/2011
USD ($)
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12/31/2010
USD ($)
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3/31/2011
USD ($)
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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