The change in the carrying amount of goodwill for the year ended December 31, 2007, is as follows (in thousands):
| Balance December 31, 2006 | $ | 261,766 | |
| Goodwill associated with acquisitions | 14,373 | ||
| Foreign currency impact | 2,600 | ||
| Balance December 31, 2007 | $ | 278,739 |
During 2007 we added $7.5 million of goodwill through our acquisition of LXSI Services, Inc. and $9.3 million in the form of an earn-out payment related to a previous acquisition. Additions to goodwill were partially offset by a $2.4 million purchase accounting adjustment to reflect the fair value of intangible assets acquired in 2006. As of December 31, 2007, we have approximately $10.0 million of potential remaining earn-out payments related to previous acquisitions that we expect to pay in 2008.
In accordance with SFAS No. 142, we annually complete an impairment test on goodwill. This impairment test did not result in any impairment losses.
A summary of our other intangible assets as of December 31 is as follows (in thousands):
| 2007 | 2006 | |||||
| Gross | $ | 29,211 | $ | 25,043 | ||
| Accumulated amortization | (14,741 | ) | (9,086 | ) | ||
| Net | $ | 14,470 | $ | 15,957 | ||
Amortization expense for other intangible assets was $5.7 million in 2007, $4.8 million in 2006, and $3.9 million in 2005. Estimated amortization expense for each of the five succeeding fiscal years based on the intangible assets at December 31, 2007, is
as follows (in thousands):
| 2008 | $ | 5,745 | |
| 2009 | 5,570 | ||
| 2010 | 1,981 | ||
| 2011 | 1,001 | ||
| 2012 | 173 | ||
| Total | $ | 14,470 |
