Segment Information (Revenues By Product Grouping) (Details) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017		Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Revenue		$ 742,365	$ 693,227	[1]	$ 1,439,557	$ 1,355,904	[1]
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenue		742,365	693,227	[2]	1,439,557	1,355,904	[2]
Operating Segments [Member] | Workspace Services revenues [Member]
Segment Reporting Information [Line Items]
Revenue	[3]	454,903	423,509	[2]	867,483	824,137	[2]
Operating Segments [Member] | Networking revenues [Member]
Segment Reporting Information [Line Items]
Revenue	[4]	207,342	196,867	[2]	415,965	390,287	[2]
Operating Segments [Member] | Content Collaboration revenues [Member]
Segment Reporting Information [Line Items]
Revenue	[5]	46,218	41,022	[2]	90,898	79,933	[2]
Operating Segments [Member] | Professional Services [Member]
Segment Reporting Information [Line Items]
Revenue	[6]	$ 33,902	$ 31,829	[2]	$ 65,211	$ 61,547	[2]

[1] As noted above, prior period amounts have not been adjusted under the modified retrospective method. See Note 2 for further information regarding the Company’s adoption of the revenue recognition standard.

[2] Prior period amounts have not been adjusted under the modified retrospective method. See Note 2 for further information regarding the Company’s adoption of the revenue recognition standard.

[3] Workspace Services revenues are primarily comprised of sales from the Company’s application virtualization products, which include XenDesktop and XenApp, the Company's enterprise mobility management products, which include XenMobile and related license updates, maintenance and subscription offerings.

[4] Networking revenues primarily include NetScaler ADC and NetScaler SD-WAN and related license updates, maintenance and subscription offerings.

[5] Content Collaboration revenues primarily include ShareFile, Podio and related

[6] Professional services revenues are primarily comprised of revenues from consulting services and product training and certification services.