Schedule of Trade Accounts Receivable (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 116,507	$ 167,625
Allowance for sales credit memos	(1,865)	(1,997)
Total accounts receivable net	114,642	165,628
Trade accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	84,167	129,007
Unbilled trade accounts receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 32,340	$ 38,618