Goodwill and Other Intangible Assets

12 Months Ended

Dec. 31, 2023

Goodwill and Intangible Assets Disclosure [Abstract]

GOODWILL AND OTHER INTANGIBLE ASSETS

The following table summarizes the carrying amount of goodwill and changes in the carrying amount of goodwill, by segment:


(in millions of dollars)	Environmental Solutions		Safety & Security Systems		Total
Balance at December 31, 2021	$	320.2	$	112.0	$	432.2
Acquisitions, including measurement period adjustments	24.0		—		24.0
Translation adjustments	(0.4)		(2.4)		(2.8)
Balance at December 31, 2022	343.8		109.6		453.4
Acquisitions, including measurement period adjustments	17.8		—		17.8
Translation adjustments	0.3		1.2		1.5
Balance at December 31, 2023	$	361.9	$	110.8	$	472.7

The following table summarizes the gross carrying amount and accumulated amortization of intangible assets for each major class of intangible assets:


	2023						2022
(in millions of dollars)	Gross Carrying Value		Accumulated Amortization		Net Carrying Value		Gross Carrying Value		Accumulated Amortization		Net Carrying Value
Definite-lived intangible assets:
Customer relationships (a)	$	161.6	$	(66.3)	$	95.3	$	153.7	$	(52.0)	$	101.7
Other (a)	8.1		(4.4)		3.7		5.7		(3.4)		2.3
Total definite-lived intangible assets	169.7		(70.7)		99.0		159.4		(55.4)		104.0
Indefinite-lived intangible assets:
Trade names	104.2		—		104.2		99.9		—		99.9
Other	4.3		—		4.3		4.3		—		4.3
Total indefinite-lived intangible assets	108.5		—		108.5		104.2		—		104.2
Total intangible assets	$	278.2	$	(70.7)	$	207.5	$	263.6	$	(55.4)	$	208.2

(a) Average useful life of customer relationships and other definite-lived intangible assets are estimated to be approximately 11 years and 6 years, respectively. The average useful life across all definite-lived intangible assets is estimated to be approximately 11 years.

The Company currently estimates that aggregate amortization expense will be approximately $15.4 million in 2024, $15.4 million in 2025, $15.3 million in 2026, $14.4 million in 2027, $13.7 million in 2028 and $24.8 million thereafter. Actual amounts of amortization may differ from estimated amounts due to additional intangible asset acquisitions, changes in foreign currency rates, measurement period adjustments for recent acquisitions, impairment of intangible assets and other events.