Stock-Based Compensation (Detail) - Summary Of Changes In RSUs Outstanding (USD $)	9 Months Ended
	Sep. 30, 2012
Restricted Stock Units (RSUs) [Member]
Outstanding	3,100,000
Per Share Weighted Average Grant Date Fair Value (in Dollars per share)	$ 21.53
Granted (1)	700,000	[1]
Granted (1) (in Dollars per share)	$ 37.97	[1]
Vested and released	(1,300,000)
Vested and released (in Dollars per share)	$ 19.51
Forfeited
Forfeited (in Dollars per share)
Outstanding	2,500,000	[2],[3]
Per Share Weighted Average Grant Date Fair Value (in Dollars per share)	$ 27.93	[2],[3]
Executive Officer [Member] | Performance Shares [Member]
Granted (1)	300,000
Non Executive [Member] | Service Based Awards [Member]
Granted (1)	400,000

[1] The 0.7 million RSUs granted in 2012 consisted of 0.3 million performance-based RSUs awarded to executives and 0.4 million service-based RSUs awarded to non-executive employees and certain board members. The 0.3 million performance-based RSUs awarded to executives represents the target amount of the award for the year, which is tied to an increase in the Company's subscription-based Research contract value ("CV") for 2012. The final number of performance-based RSUs that will be granted to executives in 2012 could range from 0% to 200% of the target amount, depending on the actual increase in CV for the year as measured on December 31, 2012. If the specified minimum level of achievement is not met, the performance-based RSUs will be forfeited in their entirety, and any compensation expense previously recorded will be reversed.

[2] The Company expects that substantially all of the outstanding awards will vest in future periods.

[3] The weighted-average remaining contractual term of the outstanding RSUs is approximately 1.2 years.