Goodwill And Other Intangible Assets (Schedule Of Change In Goodwill) (Details) $ in Thousands		3 Months Ended	9 Months Ended
		Mar. 31, 2016 USD ($) reporting_unit	Sep. 30, 2016 USD ($)	Jan. 01, 2016 USD ($)
Statement [Line Items]
Number of reporting units | reporting_unit		3
Reallocation of goodwill resulting from realignment within reportable segments				$ 86,500
Goodwill [Roll Forward]
Balance at January 1, 2016		$ 1,962,722	$ 1,962,722
Additions			2,927
Other			(625)
Balance at September 30, 2016			1,965,024
Enterprise and Service Provider [Member]
Goodwill [Roll Forward]
Balance at January 1, 2016	[1]	1,581,805	1,581,805
Additions	[2]		2,927
Other	[3]		(625)
Balance at September 30, 2016			1,584,107
GoTo Business Division [Member]
Goodwill [Roll Forward]
Balance at January 1, 2016	[1]	$ 380,917	380,917
Additions			0
Other			0
Balance at September 30, 2016			$ 380,917

[1] Beginning balance as of January 1, 2016 adjusted to reflect the Company’s re-alignment of its reporting unit structure. The change resulted in a goodwill reallocation of $86.5 million from the GoTo Business segment into the Enterprise and Service Provider segment.

[2] Amount relates to preliminary purchase price allocation of goodwill associated with the 2016 business combination. See Note 4 for more information regarding the Company's acquisitions.

[3] Amount relates to goodwill associated with the sale of the Company’s CloudPlatform and CloudPortal Business Manager products and to adjustments to the preliminary purchase price allocation associated with 2015 acquisitions. See Note 4 for more information regarding the Company's acquisitions and divestitures.