Intangible assets with estimated lives of 5 to 22 years are amortized on a straight-line or accelerated basis and are comprised of the following (in thousands):
| December 31, 2013 | December 31, 2012 | |||||||||||||||
| Gross Amount |
Accumulated Amortization |
Gross Amount |
Accumulated Amortization |
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Customer relationships |
$ | 1,147,786 | $ | 391,254 | $ | 1,156,979 | $ | 325,819 | ||||||||
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Trademarks and trade names |
151,332 | 40,397 | 152,869 | 32,653 | ||||||||||||
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Other |
21,869 | 15,182 | 28,610 | 20,746 | ||||||||||||
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| $ | 1,320,987 | $ | 446,833 | $ | 1,338,458 | $ | 379,218 | |||||||||
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