Amortization Expense of Acquired Intangibles (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Acquired Finite-Lived Intangible Assets [Line Items]
Total amortization expense	$ 2,778	$ 2,808	$ 8,360	$ 8,507
Cost Of Software License
Acquired Finite-Lived Intangible Assets [Line Items]
Total amortization expense	1,541	1,571	4,649	4,713
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	$ 5	$ 15	$ 98