Segment Information (Revenues By Product Grouping) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Revenue	$ 778,445	$ 767,170	$ 2,366,322	$ 2,427,044
Workspace [Member]
Segment Reporting Information [Line Items]
Revenue	600,036	573,342	1,780,403	1,811,936
App Delivery and Security [Member]
Segment Reporting Information [Line Items]
Revenue	155,090	166,166	511,273	532,169
Professional Services [Member]
Segment Reporting Information [Line Items]
Revenue	$ 23,319	$ 27,662	$ 74,646	$ 82,939