Segment Information (Revenues By Geographic Location) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 775,766	$ 860,945
Americas [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	426,683	484,115
EMEA [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	277,799	293,647
APJ [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenue	$ 71,284	$ 83,183