Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2011	Mar. 31, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Income Taxes [Line Items]
Income tax benefit associated with prior-year expenditures in Block P	$ 25.6			$ 25.6
Earliest years remaining open for audit and/or settlement in major taxing jurisdictions				As of September 30, 2011, the earliest years remaining open for audit and/or settlement in our major taxing jurisdictions are as follows: United States – 2008; Canada – 2006; United Kingdom – 2009; and Malaysia – 2006.
Settled uncertain tax position benefit due to a lapse of time related to the statute of limitation	6.5
United Kingdom
Income Taxes [Line Items]
Total tax rate, percentage	62.00%	50.00%
Estimated increase in tax expense due to anticipated rate increase	$ 14.5			$ 14.5
Income tax adjustment percentage in U.K			0.50%		0.20%