Goodwill And Other Intangible Assets (Schedule Of Change In Goodwill) (Details)		3 Months Ended
		Mar. 31, 2017 USD ($) reporting_unit	Dec. 31, 2016 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Statement [Line Items]
Impairment og goodwill and intangible assets		$ 0	$ 0
Number of reporting units | reporting_unit		2
Goodwill distributed to GetGo		$ 1,585,893,000	1,585,893,000	$ 1,616,817,000	$ 1,585,893,000
Goodwill [Roll Forward]
Balance at January 1, 2017		1,585,893,000
Additions	[1]	30,924,000
Other		0
Balance at March 31, 2017		$ 1,616,817,000	$ 1,585,893,000
GoTo Business Division [Member]
Statement [Line Items]
Goodwill attributable to the GoTo Business				$ 0	$ 380,917,000

[1] Amount relates to preliminary purchase price allocation of goodwill associated with the 2017 business combination. See Note 5 for more information regarding the Company's acquisitions.