There were no changes to the Company’s goodwill balance during the years ended December 31, 2019 and 2018.

The following is a summary of the Company’s acquired intangible assets as of December 31(dollars in thousands):

The estimated annual amortization of intangible assets for the next five years and thereafter is shown in the following table (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) (in thousands):

Amortization expense was $655,000, $677,000, and $581,000 for the years ended December 31, 2019, 2018, and 2017, respectively.