Intangible Assets, Net (Gross And Net Carrying Amounts For Each Major Class Of Intangible Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 5,972,612	$ 5,657,316
Accumulated amortization	(2,374,481)	(2,000,392)
Net book value	3,598,131	3,656,924
Current Contract Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	4,355,171	4,141,968
Accumulated amortization	(1,673,270)	(1,401,025)
Net book value	2,681,901	2,740,943
Network Location Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,617,441	1,515,348
Accumulated amortization	(701,211)	(599,367)
Net book value	$ 916,230	$ 915,981