INTANGIBLE ASSETS

12 Months Ended

Dec. 31, 2020

Intangible Assets, Net (Excluding Goodwill) [Abstract]

Intangible assets consist of the following (in thousands, except amortization period data):


	December 31,				Weighted- Average Amortization Period (in years)
	2020		2019
Acquired technology and data	$	131,551	$	105,168	5
Accumulated amortization	(97,791)		(90,542)
Acquired technology, net	33,760		14,626

Acquired customer base	545,643		487,532		11
Accumulated amortization	(296,758)		(233,202)
Acquired customer base, net	248,885		254,330

Acquired trade names and other intangible assets	249,465		236,358		12
Accumulated amortization	(105,365)		(84,118)
Acquired trade names and other intangible assets, net	144,100		152,240

Intangible assets, net	$	426,745	$	421,196

Amortization expense for intangible assets was approximately $88 million, $55 million and $52 million for the years ended December 31, 2020, 2019 and 2018, respectively.

In the aggregate, the Company expects the future amortization expense for intangible assets existing as of December 31, 2020 to be approximately $89 million, $70 million, $58 million, $48 million and $39 million for the years ending December 31, 2021, 2022, 2023, 2024 and 2025, respectively.

Intangible assets are reviewed for impairment at least annually and more frequently whenever events or changes in circumstances indicate that the carrying value of such assets may not be recoverable. No impairments of the Company's intangible assets were recognized during the years ended December 31, 2020, 2019 and 2018.