Intangible Assets

12 Months Ended

Dec. 31, 2018

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets

INTANGIBLE ASSETS

The following table summarizes acquired intangible assets at December 31 as follows:

		2018				2017
(In thousands)	Weighted Average Life	Gross Carrying Amount		Accumulated Amortization		Gross Carrying Amount		Accumulated Amortization
Patents	11 Years	$	2,146	$	1,716	$	2,146	$	1,629
Non-compete Agreement	4 Years	10,900		4,680		10,900		1,687
Trade Names	10 Years	11,454		5,182		11,492		4,114
Completed and Unpatented Technology	10 Years	36,406		14,964		38,114		11,931
Backlog	1 Years	8,790		8,790		14,424		12,184
Customer Relationships	15 Years	136,894		37,875		137,967		30,005
Total Intangible Assets	13 Years	$	206,590	$	73,207	$	215,043	$	61,550

Additionally, net Intangible Assets of $651 are classified in Assets Held for Sale at December 31, 2018. Refer to Note 21.

Amortization is computed on the straight-line method for financial reporting purposes, with the exception of backlog, which is amortized based on the expected realization period of the acquired backlog. Amortization expense for intangibles was $19.4 million, $12.3 million and $10.8 million for 2018, 2017 and 2016, respectively.

Based upon acquired intangible assets at December 31, 2018, amortization expense for each of the next five years is estimated to be:

(In thousands)
2019	$	16,582
2020	$	15,909
2021	$	14,000
2022	$	13,576
2023	$	12,409