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Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified | 3 Months Ended
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Mar. 31, 2012
Income Taxes [Line Items] |
Reduction in deferred tax liabilities due to statutory tax rates in Canada being lower than those in the United States | $ (5.1)
Deferred tax liabilities that have not been provided on such unremitted foreign earnings for United States Federal or state income taxes | $ 27.0

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