Note 6. Intangible Assets

The following is a summary of the Company’s acquired intangible assets (dollars in thousands):

The estimated annual amortization of intangible assets for the next five years and thereafter is shown

in the following table (in thousands):

Actual amortization expense to be reported in future periods could differ from these estimates as a result of acquisitions, divestitures, and asset impairments, among other factors. Amortization expense was $163,000 and $169,000 for the three months ended September 30, 2019 and 2018, respectively, and $491,000 and $508,000 for the nine months ended September 30, 2019 and 2018, respectively.