Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015 USD ($) revenue_source customer	Dec. 31, 2014 USD ($) customer	Dec. 31, 2013 USD ($) business customer
Significant Accounting Policies [Line Items]
Goodwill impairment loss	$ 0
Restricted cash	400,000	$ 400,000
Impairment of intangible assets	0	0
Impairment of cost method investment	0	0	$ 0
Impairment of equity method investment	0	0	$ 0
Number of businesses sold during period | business			3
Interest paid	0	1,000,000	$ 1,200,000
Income tax payments	200,000	2,000,000	$ 300,000
Redeemable noncontrolling interests	10,506,000	10,346,000
Additional paid-in capital	3,563,848,000	3,553,430,000
Noncontrolling interests	14,866,000	18,288,000
Increase (decrease) in accounts receivables, net of allowance	$ 19,902,000	23,134,000
Restatement adjustment | Correction of error, recognition of permanent equity
Significant Accounting Policies [Line Items]
Redeemable noncontrolling interests		4,100,000
Additional paid-in capital		(1,400,000)
Noncontrolling interests		$ (2,700,000)
Bolt
Significant Accounting Policies [Line Items]
Subscription period (in months)	1 month
FolioDynamix
Significant Accounting Policies [Line Items]
Goodwill impairment loss	$ 39,656,000
Initial subscription arrangement, minimum (in years)	3 years
Initial subscription arrangement, maximum (in years)	5 years
Working capital adjustment	$ 700,000
GovDelivery
Significant Accounting Policies [Line Items]
Contract cancellation period (in days)	30 days
VelocityEHS
Significant Accounting Policies [Line Items]
Number of sources of revenues | revenue_source	2
Channel Intelligence
Significant Accounting Policies [Line Items]
Proceeds from escrow releases	$ 4,000,000
Revenue | Customer concentration risk
Significant Accounting Policies [Line Items]
Number of customers represented for more than 10% of consolidated revenue | customer	0	0	0