Significant Accounting Policies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Significant Accounting Policies [Line Items]
Percentage of direct or indirect voting interest owned			more than 50%
Maintenance and customer support fees, contract life			1 year
Proceeds from escrow releases			$ 19.3
Expiry period of contingent gains associated with outstanding escrows			2 years
Actua's Consolidated Revenue
Significant Accounting Policies [Line Items]
Percentage of consolidated revenue	10.00%	10.00%	10.00%	10.00%
Msdsonline One
Significant Accounting Policies [Line Items]
Number of sources of revenues			2
Minimum
Significant Accounting Policies [Line Items]
Equity method investment, ownership percentage	20.00%		20.00%
Maximum
Significant Accounting Policies [Line Items]
Equity method investment, ownership percentage	50.00%		50.00%