Segments and Related Information (Foreign Operations) (Narrative) (Details) - USD ($) $ in Thousands			3 Months Ended		6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segments and Related Information [Line Items]
Revenue			$ 1,962,658	$ 1,569,297	$ 3,738,082	$ 2,985,901
Property and equipment, net	$ 1,101,234	$ 982,328	1,101,234		1,101,234
United States
Segments and Related Information [Line Items]
Revenue			1,900,000	1,600,000	3,700,000	2,900,000
Property and equipment, net	1,100,000	959,500	1,100,000		1,100,000
Intangible assets and goodwill, net	1,800,000	1,400,000	1,800,000		1,800,000
Foreign Operations
Segments and Related Information [Line Items]
Revenue			33,400	$ 14,000	79,900	$ 59,600
Property and equipment, net	21,500	22,800	21,500		21,500
Intangible assets and goodwill, net	$ 48,200	$ 50,500	$ 48,200		$ 48,200
Foreign Operations | Accounts Receivable, Net, Less Deferred Revenue | Geographic Concentration Risk
Segments and Related Information [Line Items]
Concentration risk, percentage of total	3.00%	5.00%
Govermment | Revenue Benchmark | Customer Concentration Risk
Segments and Related Information [Line Items]
Concentration risk, percentage of total			6.00%	2.00%	5.00%	2.00%