Intangible Assets and Goodwill (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Summary of cost, accumulated amortization and net book value of intangible assets

The cost and accumulated amortization of intangible assets subject to amortization as of December 31, 2017 and 2016, is as follows:

	2017					2016
(Thousands)	Gross Carrying Amount		Accumulated Amortization			Gross Carrying Amount		Accumulated Amortization
Customer relationships	$	40,751	$	(36,949	)	$	38,428	$	(33,823	)
Technology	13,467		(11,495		)	12,092		(10,516		)
Licenses and other	4,519		(2,672		)	4,519		(2,441		)
Total	$	58,737	$	(51,116	)	$	55,039	$	(46,780	)

Finite-lived Intangible Assets Amortization Expense

The aggregate amortization expense relating to intangible assets for the year ended December 31, 2017 and estimated amortization expense for each of the five succeeding years is as follows:

	Amortization
(Thousands)	Expense
2017	$	4,629
2018	1,932
2019	1,089
2020	642
2021	620
2022	620

Schedule of Goodwill

The balance of goodwill at December 31, 2017 and 2016 was $90.7 million and $87.0 million, respectively, and assigned to the following segments:

(Thousands)	2017		2016
Performance Alloys and Composites	$	1,899	$	1,899
Advanced Materials	50,296		46,570
Precision Coatings	38,482		38,481
Total	$	90,677	$	86,950