Acquired Intangible Assets

9 Months Ended

Sep. 30, 2021

Acquired Intangible Assets [Abstract]

Note 7. Acquired Intangible Assets

Acquired identifiable intangible assets consist of the following:

	September 30, 2021			December 31, 2020
	(In thousands)
Customer relationships	$	157,119		$	111,701
Patents, developed technology and intellectual property		14,123			723
Trademarks and trade names		8,880			6,980
Non-compete agreements		3,280			3,272
Supply agreements		800			800
Leaseholds		160			160
Total acquired intangible assets		184,362			123,636
Less accumulated amortization (1)		(76,491	)		(70,221	)
Net acquired intangible assets	$	107,871		$	53,415

(1)

Applies to all intangible assets, except for trademarks and trade names totaling $2.6 million, which have indefinite useful lives and, as such, are not being amortized.

Total amortization expense for acquired intangible assets was $2.4 million and $6.5 million for the three months and nine months ended September 30, 2021, respectively, and $2 million and $6.1 million for the comparable periods in 2020. Based on the current estimated useful lives assigned to our intangible assets, amortization expense is estimated to be $2.2 million for the remainder of 2021, $8.6 million in 2022, $8.3 million in 2023, $8.2 million in 2024 and $78 million in the aggregate for the years 2025 through 2041.

For information related to identified intangible assets acquired in the Stabil, Trombetta, and Soot Sensor acquisitions, see Note 3, “Business Acquisitions and Investments,” of the notes to our consolidated financial statements (unaudited).