Stock-Based Compensation (Detail) - Summary Of Changes In RSUs Outstanding (USD $)	12 Months Ended
	Dec. 31, 2012
Granted (1)	300,000
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)	37.98	[1]
Vested and released	(1,300,000)
Vested and released (in Dollars per share)	19.53
Outstanding	2,500,000	[2],[3]
Per Share Weighted Average Grant Date Fair Value (in Dollars per share)	27.95	[2],[3]

[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 executive personnel represented the target amount of the RSU award for the year, which was tied to an increase in the Company's subscription-based Research contract value ("CV") for 2012. The final number of performance-based RSUs granted could range from 0% to 200% of the target amount, with the final amount dependent on the actual increase in CV for the year as measured on December 31, 2012. The actual CV increase achieved for 2012 was 104.3% of the targeted amount, which resulted in the grant of 0.3 million performance-based RSUs to executives.

[2] The Company expects that substantially all of the outstanding awards at December 31, 2012 will vest in future periods.

[3] The weighted-average remaining contractual term of the outstanding RSUs is approximately 0.9 years.