Intangible Assets

12 Months Ended

Dec. 31, 2012

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets

Intangible Assets

A summary of intangible assets, net, is as follows (in thousands):

	December 31, 2012
	Gross Amount		Accumulated Amortization			Net
Customer relationships	$	42,397	$	(28,909	)	$	13,488
Intellectual property rights	4,300		(2,947		)	1,353
Proprietary technology, trade names, and patents	19,008		(19,008		)	—
Total	$	65,705	$	(50,864	)	$	14,841

	December 31, 2011
	Gross Amount		Accumulated Amortization			Net
Customer relationships	$	42,194	$	(25,529	)	$	16,665
Intellectual property rights	3,350		(2,299		)	1,051
Proprietary technology, trade names, and patents	18,985		(18,985		)	—
Total	$	64,529	$	(46,813	)	$	17,716

Total amortization expense for intangible assets for 2012, 2011 and 2010 was $3.9 million, $4.5 million and $7.4 million, respectively. A summary of the estimated amortization expense for the next five years is as follows (in thousands):

Years Ended December 31,
2013	$	3,512
2014	$	2,823
2015	$	2,411
2016	$	1,962
2017	$	1,670