7. GOODWILL AND INTANGIBLE ASSETS

Goodwill

The change in goodwill during the year is as follows (dollars in thousands):


	Years Ended December 31,
	2019		2018		2017
Balance at January 1	$	27,357	$	27,357	$	8,268
Acquired goodwill		—		—		19,089
Impairment		—		—		—
Balance at December 31	$	27,357	$	27,357	$	27,357

Impairment exists when a reporting unit’s carrying value of goodwill exceeds its fair value. Bank of the Sierra (the “Bank”) is the only subsidiary of the Company that meets the materiality criteria necessary to be deemed an operating segment, and because the Company exists primarily for the purpose of holding the stock of the Bank we have determined that only one unified operating segment (the consolidated Company) exists. At December 31, 2019, the Company had positive equity and the Company elected to perform a qualitative assessment to determine if it was more likely than not that the fair value of the Company exceeded its carrying value, including goodwill. The qualitative assessment indicated that it was more likely than not that the fair value of the reporting unit exceeded its carrying value, resulting in no impairment.

Acquired Intangible Assets

Acquired intangible assets were as follows at year-end (dollars in thousands):


	Years Ended December 31,
	2019				2018
	Gross Carrying Amount		Accumulated Amortization		Gross Carrying Amount		Accumulated Amortization
Core deposit intangibles	$	8,401	$	3,020	$	8,401	$	1,946

Aggregate amortization expense was $1,074,000, $1,020,000, and $508,000 for 2019, 2018, and 2017.

Estimated amortization expense for each of the next five years and thereafter (dollars in thousands):


2020	$	1,074
2021		1,032
2022		1,000
2023		876
2024		781
Thereafter	$	618
	$	5,381