Accounts Payable and Accrued Liabilities - Carrying Value of Accounts Payable and Accrued Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accounts Payable And Accrued Liabilities [Line Items]
Accounts payable	$ 183,672	$ 214,507
Wages, severance and related taxes	47,998	40,411
Employee benefits	18,550	16,143
Accrued rebates	28,002	33,047
Other (individual items less than 5% of total current liabilities)	71,722	61,130
Accounts payable and accrued liabilities	$ 452,482	$ 381,566