Schedule of Quantitative Information Associated with Fair Value Measurement of Level 3 (Detail) (USD $) In Thousands, unless otherwise specified			9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 Discount Rate For Revenue Earn-Out	Sep. 30, 2012 Discount Rate For Cellular Earn-Out
Fair Value Inputs, Assets, Quantitative Information
Contingent consideration, fair value	$ 16,513	$ 68,892
Earn-out discount rate			3.50%	3.50%