Segments and Related Information (Foreign Operations) (Narrative) (Details) - USD ($) $ in Thousands			3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Segments and Related Information [Line Items]
Revenue			$ 1,518,340	$ 1,396,834
Property and equipment, net	$ 799,479	$ 747,808	799,479
Intangible assets and goodwill, net	1,333,700	1,269,700	1,333,700
United States [Member]
Segments and Related Information [Line Items]
Revenue			1,400,000	1,400,000
Property and equipment, net	764,100	707,400	764,100
Intangible assets and goodwill, net	1,300,000	1,200,000	1,300,000
Foreign Operations [Member]
Segments and Related Information [Line Items]
Revenue			78,900	$ 33,800
Property and equipment, net	35,400	40,400	35,400
Intangible assets and goodwill, net	$ 62,300	$ 61,500	$ 62,300
Foreign Operations [Member] | Accounts Receivable, Net, Less BIEC [Member] | Geographic Concentration Risk [Member]
Segments and Related Information [Line Items]
Concentration risk, percentage of total	6.00%	5.00%