Goodwill and Other Intangible Assets

3 Months Ended

Mar. 31, 2019

Goodwill and Other Intangible Assets [Abstract]

Goodwill and Other Intangible Assets

Note 9.  Goodwill and Other Intangible Assets

Goodwill and other intangible assets with indefinite lives are not amortized, but instead are assessed for impairment, at least annually. The carrying amount of goodwill was $812.4 million as of March 31, 2019 and December 31, 2018.

Intangible assets subject to amortization as of March 31, 2019 and December 31, 2018 were as follows:

			Mar. 31, 2019				Dec. 31, 2018
(millions of dollars)	Weighted Average Useful Life (Years)		Gross Carrying Amount		Accumulated Amortization		Gross Carrying Amount		Accumulated Amortization
Tradenames		35	$	204.2	$	28.1	$	204.2	$	26.6
Technology		13		18.8		6.8		18.8		6.4
Patents		19		6.4		5.7		6.4		5.6
Customer relationships		22		26.5		3.5		26.5		3.2
		32	$	255.9	$	44.1	$	255.9	$	41.8

The weighted average amortization period for acquired intangible assets subject to amortization is approximately 32 years. Estimated amortization expense is $7.0 million for the remainder of 2019, $36.7 million for 2020–2023 and $168.1 million thereafter.