Intangible Assets, Net

9 Months Ended

Sep. 30, 2013

Goodwill And Intangible Assets Disclosure [Abstract]

6.	INTANGIBLE ASSETS, NET

The following table provides the gross and net carrying amounts for each major class of intangible assets:


	As of September 30, 2013							As of December 31, 2012
	Gross carrying		Accumulated			Net book		Gross carrying		Accumulated			Net book
	amount		amortization			value		amount		amortization			value
	(in thousands)
Current contract intangibles	$	2,841,948	$	(605,767	)	$	2,236,181	$	2,744,968	$	(462,016	)	$	2,282,952
Network location intangibles		1,193,367		(307,209	)		886,158		1,101,566		(250,385	)		851,181


Intangible assets, net	$	4,035,315	$	(912,976	)	$	3,122,339	$	3,846,534	$	(712,401	)	$	3,134,133

All intangible assets noted above are included in our site leasing segment. The Company amortizes its intangible assets using the straight-line method over three to fifteen years. Amortization expense relating to the intangible assets above was $68.1 million and $46.4 million for the three months ended September 30, 2013 and 2012, respectively, and $201.7 million and $124.0 million for the nine months ended September 30, 2013 and 2012, respectively. These amounts are subject to change until the preliminary allocation of the purchase price is finalized for the respective acquisition.