Segment Information - Revenues By Region (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues from External Customers [Line Items]
Total revenues	$ 2,173,350,000	$ 2,502,470,000	$ 2,376,117,000
United States and Canada [Member]
Revenues from External Customers [Line Items]
Total revenues	1,434,577,000	1,629,742,000	1,442,792,000
EMEA [Member]
Revenues from External Customers [Line Items]
Total revenues	594,264,000	663,851,000	733,732,000
Other Countries [Member]
Revenues from External Customers [Line Items]
Total revenues	$ 144,509,000	$ 208,877,000	$ 199,593,000