Segment and Related Information, Segment Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) Segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Segment and Related Information [Abstract]
Number of reportable segments | Segment	3
Segment Reporting Information [Abstract]
Net sales	$ 2,125.5	$ 1,858.3	$ 1,594.8
Income from operations	214.8	235.7	187.9
Depreciation, depletion and amortization	94.2	94.6	93.9
Segment assets	3,401.6	3,374.2	3,209.4
Capital expenditures	82.3	86.0	66.8
Segment and Related Information [Abstract]
Litigation expenses	(32.6)	0.0	(10.4)
Acquisition related transaction and integration costs	(5.1)	(4.0)	(3.1)
Income from operations	214.8	235.7	187.9
Non-operating deductions, net	(58.1)	(33.4)	(49.9)
Income before tax and equity in earnings	156.7	202.3	138.0
Performance Materials [Member]
Segment Reporting Information [Abstract]
Net sales	1,127.7	976.0	825.8
Specialty Minerals [Member]
Segment Reporting Information [Abstract]
Net sales	648.4	578.9	510.9
Refractories [Member]
Segment Reporting Information [Abstract]
Net sales	349.4	303.4	258.1
Reportable Segments [Member]
Segment Reporting Information [Abstract]
Net sales	2,125.5	1,858.3	1,594.8
Income from operations	226.1	247.2	212.1
Depreciation, depletion and amortization	94.2	94.6	93.9
Segment assets	3,355.1	3,292.2	3,069.5
Capital expenditures	81.0	83.4	66.6
Segment and Related Information [Abstract]
Income from operations	226.1	247.2	212.1
Reportable Segments [Member] | Performance Materials [Member]
Segment Reporting Information [Abstract]
Net sales	1,127.7	976.0	825.8
Income from operations	127.2	125.0	108.8
Depreciation, depletion and amortization	50.7	49.2	47.4
Segment assets	2,442.1	2,393.2	2,219.1
Capital expenditures	30.8	22.0	14.6
Segment and Related Information [Abstract]
Income from operations	127.2	125.0	108.8
Reportable Segments [Member] | Specialty Minerals [Member]
Segment Reporting Information [Abstract]
Net sales	648.4	578.9	510.9
Income from operations	41.3	72.9	67.8
Depreciation, depletion and amortization	37.2	38.4	39.6
Segment assets	609.3	605.9	559.6
Capital expenditures	39.8	51.7	46.5
Segment and Related Information [Abstract]
Income from operations	41.3	72.9	67.8
Reportable Segments [Member] | Refractories [Member]
Segment Reporting Information [Abstract]
Net sales	349.4	303.4	258.1
Income from operations	57.6	49.3	35.5
Depreciation, depletion and amortization	6.3	7.0	6.9
Segment assets	303.7	293.1	290.8
Capital expenditures	10.4	9.7	5.5
Segment and Related Information [Abstract]
Income from operations	57.6	49.3	35.5
Reconciling Item [Member]
Segment and Related Information [Abstract]
Litigation expenses	(1.5)	0.0	(10.4)
Acquisition related transaction and integration costs	(5.1)	(4.0)	(3.1)
Unallocated and Corporate [Member]
Segment Reporting Information [Abstract]
Income from operations	(4.7)	(7.5)	(10.7)
Segment assets	46.5	82.0	139.9
Capital expenditures	1.3	2.6	0.2
Segment and Related Information [Abstract]
Income from operations	$ (4.7)	$ (7.5)	$ (10.7)