Schedule of Trade Accounts Receivable (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 105,028	$ 167,638
Allowance for sales credit memos	(1,589)	(1,997)
Total accounts receivable net	103,439	165,641
Trade accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	79,717	129,020
Unbilled trade accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 25,311	$ 38,618