Note 9. Goodwill and Other Intangible Assets

The Company accounts for Other Intangible Assets under the guidance in ASC 350, Intangibles—Goodwill and Other. Under the guidance intangible assets with definite lives are amortized over their estimated useful lives. Indefinite lived intangible assets are subject to annual impairment testing. The Company capitalizes certain costs related to patent technology. Additionally, a substantial portion of the purchase price related to the Company’s acquisitions has been assigned to patents or unpatented technology, trade name, customer backlog and customer relationships. The intangibles acquired in acquisitions have been valued using a discounted cash flow approach. Intangibles, except goodwill, are being amortized over their estimated useful lives.

Intangible assets were comprised of the following as of December 31, 2015 and 2014:

 

 

Amortization expense was $7,027, $2,633 and $2,234 for the periods ended December 31, 2015, 2014 and 2013, respectively.

Estimated amortization expense for the next five years and subsequent is as follows:

 

 

Changes in the Company’s goodwill by business segment were as follows: