Intangible Assets, Net (Gross And Net Carrying Amounts For Each Major Class Of Intangible Assets) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 2,748,473	$ 2,163,468
Accumulated amortization	(647,859)	(523,684)
Net book value	2,100,614	1,639,784
Current contract intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	1,844,690	1,391,001
Accumulated amortization	(416,057)	(333,522)
Net book value	1,428,633	1,057,479
Network location intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	903,783	772,467
Accumulated amortization	(231,802)	(190,162)
Net book value	$ 671,981	$ 582,305