Unbilled Trade Accounts Receivable (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 110,413	$ 167,625
Allowance for sales credit memos	(1,762)	(1,997)
Total accounts receivable net	108,651	165,628
Trade accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	80,084	129,007
Unbilled trade accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 30,329	$ 38,618