Restructuring and Other Items, net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 29, 2019	Sep. 30, 2018	Sep. 29, 2019	Sep. 30, 2018
Restructuring Charges [Abstract]
Asset write-downs			$ 7.5	$ 0.0
Severance and other related costs			5.7
Total restructuring and other items, net	$ 0.0	$ 0.3	13.2	$ 0.7
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning of period			2.5
Additional provisions			5.7
Cash payments			(2.9)
Restructuring liability, ending of period	$ 5.3		5.3
Performance Materials [Member]
Restructuring Charges [Abstract]
Asset write-downs			4.2
Severance and other related costs			2.8
Specialty Minerals [Member]
Restructuring Charges [Abstract]
Asset write-downs			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]
Asset write-downs			1.7
Severance and other related costs			0.1
Corporate [Member]
Restructuring Charges [Abstract]
Severance and other related costs			$ 1.1