Goodwill and Other Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill [Roll Forward]
Balance Beginning	$ 781.2	$ 770.9
Change in goodwill relating to [Abstract]
Purchase price finalization	0.0	12.8
Foreign exchange translation	(2.5)	(2.5)
Total	(2.5)	10.3
Balance Ending	$ 778.7	781.2
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life	28 years
Gross Carrying Amount	$ 229.5	229.5
Accumulated Amortization	25.1	16.8
Specialty Minerals [Member]
Goodwill [Roll Forward]
Balance Beginning	13.3	13.7
Change in goodwill relating to [Abstract]
Purchase price finalization	0.0	0.0
Foreign exchange translation	(1.2)	(0.4)
Total	(1.2)	(0.4)
Balance Ending	12.1	13.3
Refractories [Member]
Goodwill [Roll Forward]
Balance Beginning	47.0	49.0
Change in goodwill relating to [Abstract]
Purchase price finalization	0.0	0.0
Foreign exchange translation	(1.3)	(2.0)
Total	(1.3)	(2.0)
Balance Ending	45.7	47.0
Performance Materials [Member]
Goodwill [Roll Forward]
Balance Beginning	544.2	453.2
Change in goodwill relating to [Abstract]
Purchase price finalization	0.0	91.1
Foreign exchange translation	0.0	(0.1)
Total	0.0	91.0
Balance Ending	544.2	544.2
Construction Technologies [Member]
Goodwill [Roll Forward]
Balance Beginning	176.7	255.0
Change in goodwill relating to [Abstract]
Purchase price finalization	0.0	(78.3)
Foreign exchange translation	0.0	0.0
Total	0.0	(78.3)
Balance Ending	$ 176.7	176.7
Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life	34 years
Gross Carrying Amount	$ 199.8	199.8
Accumulated Amortization	$ 15.3	9.3
Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life	12 years
Gross Carrying Amount	$ 18.8	18.8
Accumulated Amortization	$ 3.6	2.5
Patents & Trademarks [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life	17 years
Gross Carrying Amount	$ 6.4	6.4
Accumulated Amortization	$ 4.8	4.4
Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Weighted Average Useful Life	30 years
Gross Carrying Amount	$ 4.5	4.5
Accumulated Amortization	$ 1.4	$ 0.6