Intangible Assets

12 Months Ended

Dec. 31, 2020

Goodwill and Intangible Assets Disclosure [Abstract]

Intangible Assets

Intangible Assets

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

	December 31, 2020
	Gross Carrying Amount		Accumulated Amortization		Accumulated Impairments		Accumulated Foreign Exchange		Net Carrying Amount
Amortized Intangible Assets
Customer relationships	$	339.8	$	88.5	$	—	$	(2.9)	$	254.2
Developed technology	42.1		14.1		—		(0.2)		28.2
Trade names	32.7		1.4		20.7		0.3		10.3
Non-compete agreements	2.9		2.4		—		—		0.5
Patents	1.5		0.5		—		—		1.0
Total	$	419.0	$	106.9	$	20.7	$	(2.8)	$	294.2
Unamortized Intangible Assets
Trade names	$	20.0	$	—	$	0.1	$	(0.6)	$	20.5

	December 31, 2019
	Gross Carrying Amount		Accumulated Amortization		Accumulated Impairments		Accumulated Foreign Exchange		Net Carrying Amount
Amortized Intangible Assets
Customer relationships	$	276.3	$	67.7	$	—	$	1.8	$	206.8
Developed technology	34.0		10.9		—		0.4		22.7
Trade names	21.8		0.8		20.7		0.3		—
Non-compete agreements	2.9		2.2		—		—		0.7
Patents	1.5		0.4		—		—		1.1
Total	$	336.5	$	82.0	$	20.7	$	2.5	$	231.3
Unamortized Intangible Assets
Trade names	$	20.0	$	—	$	0.1	$	—	$	19.9

Amortization expense of intangible assets was $24.6 million, $20.3 million and $20.7 million for the years ended December 31, 2020, 2019 and 2018, 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 ending December 31,	Estimated Amortization Expense
2021	$	25.6
2022	25.5
2023	25.2
2024	24.9
2025	24.6