Segment Information (Subscription Revenues) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting Information [Line Items]
Total Subscription revenue	$ 812,111	$ 798,929	$ 1,587,877	$ 1,659,874
Subscription [Member]
Segment Reporting Information [Line Items]
Total Subscription revenue	374,271	243,450	716,400	511,686
Subscription, SaaS [Member]
Segment Reporting Information [Line Items]
Total Subscription revenue	209,634	130,618	380,715	253,188
Subscription, Non-SaaS [Member]
Segment Reporting Information [Line Items]
Total Subscription revenue	$ 164,637	$ 112,832	$ 335,685	$ 258,498