Intangible Assets, Net (Gross and Net Carrying Amounts for each Major Class of Intangible Assets) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 6,176,181	$ 6,064,275
Accumulated amortization	(2,938,150)	(2,732,810)
Net book value	3,238,031	3,331,465
Current Contract Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	4,476,184	4,394,416
Accumulated amortization	(2,076,957)	(1,928,030)
Net book value	2,399,227	2,466,386
Network Location Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,699,997	1,669,859
Accumulated amortization	(861,193)	(804,780)
Net book value	$ 838,804	$ 865,079