Acquisitions - Additional Information (Detail) (USD $)	0 Months Ended		3 Months Ended		9 Months Ended			1 Months Ended	9 Months Ended	0 Months Ended	9 Months Ended		0 Months Ended		3 Months Ended	9 Months Ended
	Sep. 30, 2014 Investment	Dec. 31, 2013 Investment	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Oct. 31, 2014 Subsequent Event [Member] Entity	Sep. 30, 2014 PayScale [Member]	Feb. 28, 2014 KnowledgeAdvisors, Inc. [Member]	Sep. 30, 2014 KnowledgeAdvisors, Inc. [Member]	Feb. 28, 2014 KnowledgeAdvisors, Inc. [Member]	Jan. 14, 2014 Talent Neuron [Member]	Jan. 14, 2014 Talent Neuron [Member]	Sep. 30, 2014 Senior Subordinated Convertible Promissory Note [Member] Entity	Sep. 30, 2014 Senior Subordinated Convertible Promissory Note [Member]
Business Acquisition [Line Items]
Equity interests in acquiree												100.00%
Purchase price, net of cash acquired					$ 58,902,000					$ 50,900,000
Intangible assets acquired												24,000,000
Amortization period										4 years			3 years
Goodwill related primarily to workforce												35,000,000
Deferred tax liability												9,600,000
Deferred tax assets, net operating loss carryforwards											3,100,000
Deferred revenue amount recognized										(3,600,000)
Proforma deferred revenue			1,703,000	1,367,000	4,937,000	8,826,000					2,900,000
Initial cash payment to acquire business													8,000,000
Company allocation to intangible assets														1,700,000
Non deductible to tax purposes														6,300,000
Additional investments in private entity					3,735,000	11,213,000		4,800,000							2,600,000
Number of private entity investments								1							1
Convertible note maturity date																Aug. 12, 2018
Convertible note interest rate															8.00%	8.00%
Debt instrument, convertible type of investee's equity																Further, the Convertible Note provides an automatic conversion to preferred shares upon the investee's equity financing event. The Company has bifurcated the automatic conversion feature since it represents an embedded derivative. The Company has accounted for the Convertible Note as an available-for-sale security.
Fair value of the convertible note and the bifurcated automatic conversion feature amount															2,700,000	2,700,000
Carrying value of company's investment					6,585,000				6,600,000
Number of investment	5	5
Carrying value of company's investment			$ 21,200,000		$ 21,200,000		$ 14,600,000