Revision of Prior Period Financial Statements - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended	3 Months Ended	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012 Technology-Related Investment Funds [Member]	Dec. 31, 2011 Technology-Related Investment Funds [Member]	Dec. 31, 2012 Adjustments Related to Insignificant Variances in Deferred Revenue [Member]	Dec. 31, 2011 Adjustments Related to Insignificant Variances in Deferred Revenue [Member]	Dec. 31, 2013 Income Tax Expense [Member]	Jun. 30, 2013 Income Tax Expense [Member]	Dec. 31, 2012 Income Tax Expense [Member]	Sep. 30, 2012 Income Tax Expense [Member]	Dec. 31, 2012 Income Tax Expense [Member]	Dec. 31, 2011 Research Service Revenue [Member]
Adjustments related to prior period		$ 0.5	$ (1.4)	$ 0.1	$ (0.4)	$ 0.1	$ 0.8	$ 0.1	$ 0.4	$ 0.4	$ 0.1
Revised Consolidated Statements of Comprehensive Income Description	The consolidated statements of comprehensive income for all periods is impacted by the same amount as net income for the respective period.

- Definition

Description of a prior period adjustment to previously issued financial statements, including an adjustment that is a correction of an error. At a minimum, the description may include the nature and reasons for the adjustment and the periods affected by the adjustment, as well as (1) the effect of the correction on each financial statement line item and any per-share amounts affected for each prior period presented (2) the cumulative effect of the change on retained earnings or other appropriate components of equity or net assets in the statement of financial position, as of the beginning of the earliest period presented, and (3) the effect of the prior period adjustment (both gross and net of applicable income tax) on the net income of each prior period presented in the entity's annual report for the year in which the adjustments are made.

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