Revenue Recognition (Disaggregation of Revenue by Principal Geographic Area, Based on Customers' Domiciles) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 721,789	$ 605,303	$ 1,985,717	$ 1,801,462
United States
Disaggregation of Revenue [Line Items]
Total revenue	454,836	380,184	1,257,617	1,127,347
Europe, the Middle East and Africa
Disaggregation of Revenue [Line Items]
Total revenue	147,193	122,050	400,928	368,636
Asia Pacific Region
Disaggregation of Revenue [Line Items]
Total revenue	77,401	64,648	212,663	188,756
Canada
Disaggregation of Revenue [Line Items]
Total revenue	28,710	24,334	78,314	75,212
Latin America
Disaggregation of Revenue [Line Items]
Total revenue	$ 13,649	$ 14,087	$ 36,195	$ 41,511