Intangible Assets, Net (Gross and Net Carrying Amounts for each Major Class of Intangible Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 6,064,275	$ 5,972,612
Accumulated amortization	(2,732,810)	(2,374,481)
Net book value	3,331,465	3,598,131
Current Contract Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	4,394,416	4,355,171
Accumulated amortization	(1,928,030)	(1,673,270)
Net book value	2,466,386	2,681,901
Network Location Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,669,859	1,617,441
Accumulated amortization	(804,780)	(701,211)
Net book value	$ 865,079	$ 916,230