Intangible Assets, Net (Gross And Net Carrying Amounts For Each Major Class Of Intangible Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 5,839,647	$ 5,657,316
Accumulated amortization	(2,288,937)	(2,000,392)
Net book value	3,550,710	3,656,924
Current Contract Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	4,284,068	4,141,968
Accumulated amortization	(1,612,010)	(1,401,025)
Net book value	2,672,058	2,740,943
Network Location Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,555,579	1,515,348
Accumulated amortization	(676,927)	(599,367)
Net book value	$ 878,652	$ 915,981