Goodwill and Other Intangible Assets

We are required to review goodwill and indefinite-lived intangible assets annually for impairment. Goodwill impairment is tested at the graphite electrodes reporting unit level on an annual basis and between annual tests if an event occurs or circumstances change that would more likely than not reduce the fair value of a reporting unit below its carrying value.

The following tables represent the changes in the carrying value of goodwill and intangibles for the nine months ended September 30, 2019 which are reported in "Other assets" on the balance sheets:



Goodwill
(Dollars in thousands)
Balance as of December 31, 2018	$	171,117
Adjustments	—
Balance as of September 30, 2019	$	171,117



Intangible Assets
	As of September 30, 2019							As of December 31, 2018
	Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization			Net Carrying Amount
	(Dollars in Thousands)
Trade name	$	22,500	$	(9,336	)	$	13,164	$	22,500	$	(7,721	)	$	14,779
Technological know-how	55,300		(27,808		)	27,492		55,300		(23,503		)	31,797
Customer–related intangible	64,500		(18,377		)	46,123		64,500		(15,070		)	49,430
Total finite-lived intangible assets	$	142,300	$	(55,521	)	$	86,779	$	142,300	$	(46,294	)	$	96,006

Amortization expense of acquired intangible assets was $3.0 million and $3.2 million in the three months ended September 30, 2019 and 2018, respectively, and $9.2 million and $9.8 million in the nine months ended September 30, 2019 and 2018, respectively. Estimated amortization expense will approximate $2.9 million in the remainder of 2019, $11.4 million in 2020, $10.7 million in 2021, $10.1 million in 2022 and $9.2 million in 2023.