Other Income (Loss), Net - Additional Information (Detail) (USD $)	12 Months Ended				0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012	Dec. 27, 2012	Jul. 11, 2012	Sep. 30, 2012
Schedule Of Other Nonoperating Income Expense [Line Items]
Gain (loss) on sales/distributions of ownership interests	$ 5,158,000	$ (4,032,000)		$ 5,260,000
Gain on fair value of prior equity interests				51,668,000
Carrying value		775,000	[1]
Realized gains on sales of marketable securities		100,000		1,400,000
Proceed from sale of securities		760,000		7,632,000
Active Network Inc
Schedule Of Other Nonoperating Income Expense [Line Items]
Gain (loss) on sales/distributions of ownership interests		800,000		7,500,000
Symbio
Schedule Of Other Nonoperating Income Expense [Line Items]
Equity method cash	8,100,000
Deferred gain on sale	800,000
Gain (loss) on sales/distributions of ownership interests	4,300,000
Bolt
Schedule Of Other Nonoperating Income Expense [Line Items]
Gain on fair value of prior equity interests					25,500,000
Free Borders
Schedule Of Other Nonoperating Income Expense [Line Items]
Gain (loss) on sales/distributions of ownership interests		300,000
CIML
Schedule Of Other Nonoperating Income Expense [Line Items]
Gain on fair value of prior equity interests						26,200,000
WhiteFence
Schedule Of Other Nonoperating Income Expense [Line Items]
Equity method cash		5,400,000
Deferred gain on sale		1,600,000
Gain (loss) on sales/distributions of ownership interests		(4,300,000)
Go Industry
Schedule Of Other Nonoperating Income Expense [Line Items]
Gain (loss) on sales/distributions of ownership interests				2,900,000
Sale Proceeds				2,900,000
Carrying value							0
ICE
Schedule Of Other Nonoperating Income Expense [Line Items]
Gain (loss) on sales/distributions of ownership interests				1,700,000
Realized gains on sales of marketable securities				100,000
Number of Shares Distributed has Escrowed Proceeds Related to the Disposition of a Former Company				12,989
Proceed from sale of securities				$ 1,800,000

[1] Includes (Actua voting ownership): Acquirgy (25%).