INTANGIBLE ASSETS

12 Months Ended

Dec. 31, 2020

INTANGIBLE ASSETS

INTANGIBLE ASSETS

5. INTANGIBLE ASSETS

Intangible assets on the Company’s consolidated balance sheets consist of the following (in thousands):

		December 31, 2020						December 31, 2019
		Gross		Accumulated		Net Book		Gross		Accumulated		Net Book
	Life	Amount		amortization		Value		Amount		amortization		Value
Customer lists	8 - 17 years	$	69,833	$	(23,636)	$	46,197	$	64,314	$	(19,311)	$	45,003
Trade name	10 - 19 years		14,055		(5,061)		8,994		12,222		(4,114)		8,108
Design and technologies	10 - 15 years		15,531		(4,874)		10,657		12,927		(3,554)		9,373
Patents	17 years		24		(13)		11		24		(11)		13
Total		$	99,443	$	(33,584)	$	65,859	$	89,487	$	(26,990)	$	62,497

Intangible assets resulting from the acquisition of Dynamic Controls were approximately $7,800 (Note 2). The intangible assets acquired consist of customer lists, technology, and a trade name.

Total amortization expense for intangible assets for the years 2020, 2019 and 2018 was $5,928, $5,718 and $3,655, respectively.

Estimated amortization expense for intangible assets is as follows (in thousands):

	Estimated
	Amortization Expense
2021	$	6,059
2022		6,110
2023		6,127
2024		5,798
2025		5,780
Thereafter		35,985
Total estimated amortization expense	$	65,859