Segments and Related Information (Foreign Operations) (Narrative) (Details) - USD ($) $ in Thousands			3 Months Ended		9 Months Ended
	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Segments and Related Information [Line Items]
Revenue			$ 1,955,752	$ 1,586,181	$ 5,004,116	$ 3,792,811
Property and equipment, net	$ 691,430	$ 549,084	691,430		691,430
Intangible assets and goodwill, net	1,330,900	1,175,600	1,330,900		1,330,900
United States [Member]
Segments and Related Information [Line Items]
Revenue			1,900,000	1,500,000	4,800,000	3,600,000
Property and equipment, net	629,200	475,300	629,200		629,200
Intangible assets and goodwill, net	1,200,000	1,100,000	1,200,000		1,200,000
Foreign Operations [Member]
Segments and Related Information [Line Items]
Revenue			61,000	$ 73,800	160,700	$ 222,800
Property and equipment, net	62,200	73,800	62,200		62,200
Intangible assets and goodwill, net	$ 114,300	$ 107,800	$ 114,300		$ 114,300
Foreign Operations [Member] | Accounts Receivable, Net, Less Billings in Excess of Costs and Earnings [Member] | Geographic Concentration Risk [Member] | Foreign Customers [Member]
Segments and Related Information [Line Items]
Concentration risk, percentage of total	6.00%	8.00%