Segment Information (Subscription Revenues) (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]
Total Subscription revenue	$ 778,445	$ 767,170	$ 2,366,322	$ 2,427,044
Subscription [Member]
Segment Reporting Information [Line Items]
Total Subscription revenue	383,154	262,604	1,099,554	774,290
Subscription, SaaS [Member]
Segment Reporting Information [Line Items]
Total Subscription revenue	228,515	137,831	609,230	391,019
Subscription, Non-SaaS [Member]
Segment Reporting Information [Line Items]
Total Subscription revenue	$ 154,639	$ 124,773	$ 490,324	$ 383,271