Restructuring and Other Items, net (Tables)

12 Months Ended

Dec. 31, 2020

Restructuring and Other Items, net [Abstract]

Restructuring Charges by Segment

The following table outlines the amount of restructuring charges recorded within the Consolidated Statements of Income and the segments they relate to:

Restructuring and Other Items, net	Year Ended December 31,
(millions of dollars)	2020		2019		2018
Asset Write-Downs
Performance Materials	$	—	$	4.2	$	—
Specialty Minerals		7.1		1.6		0.7
Energy Services		—		1.7		—
Total asset write-down charges	$	7.1	$	7.5	$	0.7
Severance and other employee costs
Performance Materials	$	—	$	2.8	$	—
Specialty Minerals		0.3		0.9		—
Refractories		—		0.8		—
Energy Services		—		0.1		1.8
Corporate		—		1.1		—
Total severance and other employee costs	$	0.3	$	5.7	$	1.8
Other
Specialty Minerals	$	0.2	$	—	$	—
Total restructuring and other items, net	$	7.6	$	13.2	$	2.5

Reconciliation of Restructuring Liability

The following table is a reconciliation of our restructuring liability balance as of December 31, 2020 and 2019:

	December 31,
(millions of dollars)	2020			2019
Restructuring liability, beginning of period	$	5.0		$	2.5
Additional provisions		0.3			5.7
Cash payments		(1.6	)		(3.2	)
Other		(0.1	)		—
Restructuring liability, end of period	$	3.6		$	5.0