Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Income Taxes [Line Items]
Income tax benefits attributable to employee stock option transactions	$ 8,775,000	$ 15,896,000	$ 6,035,000
Increase in deferred tax asset valuation allowance related to foreign exploration expenditures	102,714,000	47,128,000	34,431,000
Undistributed earnings of subsidiaries considered indefinitely invested	4,895,000,000
Unrecognized deferred tax liability	492,469,000
Withholding tax on any monies repatriated from Canada to the U.S.	5.00%
Other recorded liabilities for interest and penalties	976,000	1,010,000
Income tax expense, (charges) benefits for interest and penalties	34,000	(43,000)	1,763,000
Earliest years remaining open for audit and/or settlement in major taxing jurisdictions	As of December 31, 2011, the earliest years remaining open for audit and/or settlement in our major taxing jurisdictions are as follows: United States – 2008; Canada – 2007; United Kingdom – 2010; and Malaysia – 2006.
Minimum
Income Taxes [Line Items]
Income tax uncertainties threshold, percentage of tax benefit more likely to be measured and recognized	50.00%
Expected liability to be added for uncertain taxes for 2012 events	1,000,000
Maximum
Income Taxes [Line Items]
Expected liability to be added for uncertain taxes for 2012 events	2,000,000
Foreign Country
Income Taxes [Line Items]
Increase in deferred tax asset valuation allowance related to foreign exploration expenditures	$ 140,493,000
Foreign Country | Minimum
Income Taxes [Line Items]
Foreign tax credit carryforwards expiration year	2014
Foreign Country | Maximum
Income Taxes [Line Items]
Foreign tax credit carryforwards expiration year	2020