Business Acquisition (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Business Combination, Contingent Consideration, Liability	$ 20,000	$ 15,000
Goodwill, Purchase Accounting Adjustments	5,546
Goodwill, Acquired During Period	136,768
Goodwill	772,916	635,675
Business Acquisition, Purchase Price Allocation, Goodwill, Expected Tax Deductible Amount	112,100
Business Acquisition Contributed Total Revenue	20,100
Total consideration of transaction, net of cash acquired	265,556
Salesify [Member]
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	17,000
Business Combination, Contingent Consideration, Liability	4,000
j2 Cloud Services, Inc. [Member]
Goodwill, Purchase Accounting Adjustments	9,837
Business Cloud Services Segment [Member]
Goodwill, Acquired During Period	102,068
Goodwill	496,906	390,063
Digital Media Segment [Member]
Goodwill, Purchase Accounting Adjustments	(4,291)
Goodwill, Acquired During Period	34,700
Goodwill	$ 276,010	$ 245,612