Description of Business and Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Date of Incorporation	Mar. 06, 2003
Concentration risk, maximum exposure percentage	5.00%
Allowance for Doubtful Accounts Receivable [Roll Forward]
Allowance for doubtful accounts receivable, beginning balance	$ 11,944	$ 6,138	$ 3,774
Add: bad debt expense	11,873	10,273	4,130
Less: write-offs, net of recoveries and other adjustments	(5,847)	(4,467)	(1,766)
Allowance for doubtful accounts receivable, ending balance	17,970	11,944	6,138
Advertising expense	$ 20,000	5,700	3,900
Requisite service period to receive stock-based compensation	4 years
Rental expense for leased office space	$ 117,500	$ 94,200	$ 54,900
Deferred commissions, general length of non-cancelable terms of customer contracts	12 months
Marketing Solutions [Member]
Allowance for Doubtful Accounts Receivable [Roll Forward]
General length of advertising contract	2 months
Hiring Solutions [Member]
Allowance for Doubtful Accounts Receivable [Roll Forward]
General length of advertising contract	30 days
Sales Solution Subscription [Member]
Allowance for Doubtful Accounts Receivable [Roll Forward]
General length of advertising contract	12 months
Maximum [Member] | Premium Subscriptions [Member]
Allowance for Doubtful Accounts Receivable [Roll Forward]
General length of advertising contract	12 months
Minimum [Member] | Premium Subscriptions [Member]
Allowance for Doubtful Accounts Receivable [Roll Forward]
General length of advertising contract	1 month