Segment Information (Revenues By Product Grouping) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segment Reporting Information [Line Items]
Net revenues		$ 690,925	$ 668,736	$ 2,046,829	$ 2,001,496
Operating Segments [Member]
Segment Reporting Information [Line Items]
Net revenues		690,925	668,736	2,046,829	2,001,496
Operating Segments [Member] | Workspace Services revenues [Member]
Segment Reporting Information [Line Items]
Net revenues	[1]	431,592	412,773	1,255,728	1,222,786
Operating Segments [Member] | Networking revenues [Member]
Segment Reporting Information [Line Items]
Net revenues	[2]	185,539	191,243	575,827	581,612
Operating Segments [Member] | Data revenues [Member]
Segment Reporting Information [Line Items]
Net revenues	[3]	41,632	34,806	121,566	99,615
Operating Segments [Member] | Professional Services [Member]
Segment Reporting Information [Line Items]
Net revenues	[4]	$ 32,162	$ 29,914	$ 93,708	$ 97,483

[1] 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 and maintenance and support

[2] Networking revenues primarily include NetScaler ADC and NetScaler SD-WAN, related license updates and maintenance and support

[3] Data revenues primarily include ShareFile, Podio, and related cloud offerings

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