Other Intangible Assets

The following is a summary of the Company’s other intangible assets as of March 31, 2018 and December 31, 2017 (in thousands):



	March 31, 2018			December 31, 2017			Weighted Average Life
Customer lists	$	75,124		$	74,615		14.5
Non-compete agreements	974			964			4.0
Trade names	2,510			2,510			13.3
Patents	57			57			9.0
	78,665			78,146
Less accumulated amortization	(52,024		)	(50,583		)
Intangible assets, net	$	26,641		$	27,563

In accordance with ASC 350, the Company amortizes its intangible assets with finite lives over their respective estimated useful lives and reviews for impairment whenever impairment indicators exist. Impairment indicators could include significant under-performance relative to the historical or projected future operating results, significant changes in the manner of use of assets, significant negative industry or economic trends or significant changes in the Company’s market capitalization relative to net book value. Any changes in key assumptions used by the Company, including those set forth above, could result in an impairment charge and such a charge could have a material adverse effect on the Company’s consolidated results of operations. The Company’s intangible assets consist of customer lists, non-compete agreements, trade names and patents. The Company’s customer lists, which have an estimated weighted-average useful life of approximately fourteen and a half years, are being amortized using the economic life method. The Company’s non-compete agreements, trade names and patents are being amortized on a straight-line basis over their estimated weighted-average useful lives of approximately four years, thirteen years and nine years, respectively.

Amortization expense related to these intangible assets was $1.2 million and $1.2 million for the three months ended March 31, 2018 and 2017, respectively.

The estimated amortization expense for the remainder of 2018 and each of the next five years and thereafter is as follows (in thousands):



Remainder of 2018	$	3,454
2019	4,372
2020	4,201
2021	3,896
2022	3,431
Thereafter	7,287
	$	26,641