Estimated Amortization Expense for Definite-Lived Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Expected Amortization Expense [Line Items]
2012	$ 562
2013	2,192
2014	2,007
2015	1,755
2016	607
Thereafter	320
Net Carrying Amount	7,443	609
Cost of revenues
Expected Amortization Expense [Line Items]
2012	300
2013	1,200
2014	1,200
2015	1,200
2016	400
Thereafter	$ 300