Acquisitions - Additional Information (Detail) $ in Thousands, Subscriber in Millions							1 Months Ended	12 Months Ended
	Nov. 02, 2015 USD ($)	Jun. 01, 2015 USD ($)	Nov. 03, 2014 USD ($) Brand	Sep. 02, 2014 USD ($)	Jun. 13, 2014 USD ($)	Apr. 21, 2014 USD ($)	Oct. 31, 2015 USD ($)	Dec. 31, 2015 USD ($) Subscriber Clients	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Business Acquisition [Line Items]
Purchase price of acquisition								$ 94,376	$ 398,060
Purchase price allocation, goodwill recorded								1,915,690	1,884,920	$ 1,671,205
Number of brands | Brand			2
Total acquisition costs expensed								3,100	3,500	$ 1,200
Revenue								$ 71,900	$ 74,700
911 Enable [Member]
Business Acquisition [Line Items]
Date of acquisition								Sep. 02, 2014
Purchase price of acquisition				$ 42,400
Purchase price allocation, goodwill recorded				21,289
Preliminary purchase price allocation, intangible assets recorded				$ 20,685
Health Advocate [Member]
Business Acquisition [Line Items]
Date of acquisition								Jun. 13, 2014
Purchase price of acquisition					$ 265,900
Purchase price allocation, goodwill recorded					156,014
Preliminary purchase price allocation, intangible assets recorded					$ 151,990
Estimated number of Americans served by entity | Subscriber								10
Health Advocate [Member] | Minimum [Member]
Business Acquisition [Line Items]
Number client relationships | Clients								10,000
School Reach [Member]
Business Acquisition [Line Items]
Date of acquisition			Nov. 03, 2014
Purchase price of acquisition			$ 13,500
Purchase price allocation, goodwill recorded			6,923
Preliminary purchase price allocation, intangible assets recorded			7,350
Working capital adjustment			$ 1,000
School Messenger [Member]
Business Acquisition [Line Items]
Date of acquisition								Apr. 21, 2014
Purchase price of acquisition						$ 77,400
Purchase price allocation, goodwill recorded						50,386
Preliminary purchase price allocation, intangible assets recorded						$ 40,145
Sharp School [Member]
Business Acquisition [Line Items]
Date of acquisition								Jun. 01, 2015
Purchase price of acquisition		$ 17,200
Purchase price allocation, goodwill recorded		8,254
Preliminary purchase price allocation, intangible assets recorded		$ 9,092
ClientTell [Member]
Business Acquisition [Line Items]
Date of acquisition								Nov. 02, 2015
Purchase price of acquisition	$ 38,400
Additional cash to be paid	$ 10,500
Additional cash to be paid over the period in years	5 years
Contingent consideration arrangement	$ 5,400
Purchase price allocation, goodwill recorded	14,967
Preliminary purchase price allocation, intangible assets recorded	$ 26,300
Magnetic North [Member]
Business Acquisition [Line Items]
Date of acquisition								Oct. 31, 2015
Purchase price of acquisition							$ 38,700
Purchase price allocation, goodwill recorded							24,579
Preliminary purchase price allocation, intangible assets recorded							$ 16,361