Segment Information (Revenues By Geographic Location) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 778,445	$ 767,170	$ 2,366,322	$ 2,427,044
Americas [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	427,978	414,341	1,312,053	1,330,666
EMEA [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	268,700	276,494	821,895	847,454
APJ [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 81,767	$ 76,335	$ 232,374	$ 248,924