Accounts Receivable - Components of Accounts Receivable (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross accounts receivable	$ 169,401	$ 156,790
Accounts receivable reserves	(669)	(1,560)
Accounts receivable, net	$ 168,732	$ 155,230