8. OTHER INTANGIBLE ASSETS, NET

Intangible assets are generally the result of acquisitions and consist primarily of purchased technology, customer related intangibles, and trademarks. Intangible assets are amortized over useful lives that generally range between 1 and 20 years.

The following tables present the cumulative composition of the Corporation’s intangible assets as of December 31, 2017 and December 31, 2016, respectively.



	2017							2016
(In thousands)	Gross		Accumulated Amortization			Net		Gross		Accumulated Amortization			Net
Technology	$	243,440	$	(114,036	)	$	129,404	$	166,859	$	(98,266	)	$	68,593
Customer related intangibles	367,230		(180,580		)	186,650		349,742		(157,154		)	192,588
Other intangible assets	40,640		(27,026		)	13,614		36,709		(26,429		)	10,280
Total	$	651,310	$	(321,642	)	$	329,668	$	553,310	$	(281,849	)	$	271,461

During the year ended December 31, 2017, the Corporation acquired intangible assets of $88.9 million which included Technology of $73.0 million, Customer-related intangibles of $12.9 million, and Other intangible assets of $3.0 million. The weighted average amortization periods for these aforementioned intangible assets are 15.0 years, 16.3 years, and 7.0 years, respectively.

Amortization expense from continuing operations for the years ended December 31, 2017, 2016, and 2015 was $38.4 million, $33.4 million, and $34.8 million, respectively. The estimated future amortization expense of intangible assets over the next five years is as follows:



(In thousands)
2018	$	38,159
2019	36,405
2020	34,440
2021	32,644
2022	30,085