Amortization Expense of Acquired Intangibles (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Acquired Finite-Lived Intangible Assets [Line Items]
Total amortization expense	$ 2,772	$ 2,778	$ 8,322	$ 8,360
Cost of software license
Acquired Finite-Lived Intangible Assets [Line Items]
Total amortization expense	1,540	1,541	4,622	4,649
Selling and marketing
Acquired Finite-Lived Intangible Assets [Line Items]
Total amortization expense	1,232	1,232	3,696	3,696
General and administrative
Acquired Finite-Lived Intangible Assets [Line Items]
Total amortization expense		$ 5	$ 4	$ 15