Restructuring and Other Items, net (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018	Jun. 30, 2019	Jul. 01, 2018
Restructuring and Other Items, net [Abstract]
Annualized savings expected from restructuring program			$ 12.0
Restructuring Charges [Abstract]
Impairment of assets charges	$ 7.5		7.5	$ 0.0
Severance and other related costs	5.7
Total restructuring and other items, net	13.2	$ 0.4	13.2	$ 0.4
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning of period			2.5
Additional provisions			5.7
Cash payments			(1.1)
Restructuring liability, ending of period	7.1		$ 7.1
Performance Materials [Member]
Restructuring Charges [Abstract]
Impairment of assets charges	4.2
Severance and other related costs	2.8
Specialty Minerals [Member]
Restructuring Charges [Abstract]
Impairment of assets charges	1.6
Severance and other related costs	0.9
Refractories [Member]
Restructuring Charges [Abstract]
Severance and other related costs	0.8
Energy Services [Member]
Restructuring Charges [Abstract]
Impairment of assets charges	1.7
Severance and other related costs	0.1
Corporate [Member]
Restructuring Charges [Abstract]
Severance and other related costs	$ 1.1