Noncash Operating Working Capital (Increased) Decreased (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Working Capital Detail [Line Items]
Accounts receivable	$ (309,322)	$ (43,630)	$ (4,363)
Inventories	(157,657)	(59,413)	(28,231)
Prepaid expenses	(242,771)	20,548	14,567
Deferred income tax assets	(1,554)	8,488	(80,073)
Accounts payable and accrued liabilities	269,634	(478,580)	766,113
Current income tax liabilities	40,567	(273,118)	(28,401)
Net (increase) decrease in noncash operating working capital	$ (401,103)	$ (825,705)	$ 639,612