Goodwill and Other Intangible Assets (Tables)

12 Months Ended

Dec. 31, 2020

Goodwill and Other Intangible Assets [Abstract]

Goodwill

The balance of goodwill by segment and the activity occurring in the past two fiscal years is as follows:

(millions of dollars)	Performance Materials			Specialty Minerals		Refractories			Consolidated
Balance at December 31, 2018	$	755.9		$	12.3	$	44.2		$	812.4
Change in goodwill relating to:
Foreign exchange translation		(4.7	)		0.2		(0.5	)		(5.0	)
Total Changes	$	(4.7	)	$	0.2	$	(0.5	)	$	(5.0	)
Balance at December 31, 2019	$	751.2		$	12.5	$	43.7		$	807.4
Change in goodwill relating to:
Foreign exchange translation		1.2			0.2		(0.3	)		1.1
Total Changes	$	1.2		$	0.2	$	(0.3	)	$	1.1
Balance at December 31, 2020	$	752.4		$	12.7	$	43.4		$	808.5

Other Intangible Assets

Acquired intangible assets subject to amortization as of December 31, 2020 and December 31, 2019 were as follows:

			December 31, 2020				December 31, 2019
	Weighted Average Useful Life (Years)		Gross Carrying Amount		Accumulated Amortization		Gross Carrying Amount		Accumulated Amortization
Tradenames		35	$	203.9	$	38.6	$	203.9	$	32.5
Technology		13		18.8		9.6		18.8		8.0
Patents and trademarks		19		6.4		6.1		6.4		5.9
Customer relationships		22		26.9		5.9		24.7		4.4
		32	$	256.0	$	60.2	$	253.8	$	50.8