Intangible Assets, Net (Gross And Net Carrying Amounts For Each Major Class Of Intangible Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 5,705,117	$ 5,657,316
Accumulated amortization	(2,099,569)	(2,000,392)
Net book value	3,605,548	3,656,924
Current Contract Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	4,179,583	4,141,968
Accumulated amortization	(1,473,948)	(1,401,025)
Net book value	2,705,635	2,740,943
Network Location Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,525,534	1,515,348
Accumulated amortization	(625,621)	(599,367)
Net book value	$ 899,913	$ 915,981