Intangible Assets

12 Months Ended

Dec. 31, 2015

Goodwill and Intangible Assets Disclosure [Abstract]

The gross carrying amount and accumulated amortization for intangible assets consisted of the following ($ in millions):



	December 31, 2015						December 31, 2014
	Gross Carrying Amount		Accumulated Amortization*		Net Carrying Amount		Gross Carrying Amount		Accumulated Amortization*		Net Carrying Amount
Amortized intangible assets
Engineered Papers
Customer-related intangibles	$	10.0	$	10.0	$	—	$	10.0	$	10.0	$	—
Advanced Materials & Structures
Customer Relationships	167.7		6.4		161.3		52.4		2.1		50.3
Developed Technology	16.0		2.4		13.6		16.0		1.2		14.8
Customer Contracts	0.9		0.5		0.4		0.9		—		0.9
Non-Compete Agreements	1.7		0.1		1.6		—		—		—
Patents	1.5		0.1		1.4		1.5		—		1.5
Total	$	197.8	$	19.5	$	178.3	$	80.8	$	13.3	$	67.5

Unamortized intangible assets (Advanced Materials & Structures)
Trade names	$	35.6					$	21.8

* Accumulated amortization also includes adjustments for foreign currency translation.

Amortization expense of intangible assets was $5.6 million, $3.1 million and $0.6 million and for the years ended December 31, 2015, 2014 and 2013, respectively. Finite-lived intangibles in the AMS segment are expensed using the straight-line amortization method.

The following table shows the estimated aggregate amortization expense for the next five years ($ in millions):



For the year ended December 31,	Estimated Amortization Expense
2016	$	12.3
2017	11.9
2018	11.9
2019	11.8
2020	11.5