Goodwill and Other Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Goodwill [Roll Forward]
Balance Beginning	$ 64.4us-gaap_Goodwill	$ 65.8us-gaap_Goodwill
Change in goodwill relating to [Abstract]
Acquisition	708.2us-gaap_GoodwillAcquiredDuringPeriod
Foreign exchange translation	(1.7)us-gaap_GoodwillTranslationAdjustments	(1.4)us-gaap_GoodwillTranslationAdjustments
Total	706.5us-gaap_GoodwillPeriodIncreaseDecrease	(1.4)us-gaap_GoodwillPeriodIncreaseDecrease
Balance Ending	770.9us-gaap_Goodwill	64.4us-gaap_Goodwill
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	223.6	9.3
Accumulated Amortization	11.5	6.3
Weighted Average Useful Life (Years)	28 years
Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	191.2	0
Accumulated Amortization	3.7	0
Weighted Average Useful Life (Years)	34 years
Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	18.7	0
Accumulated Amortization	1.0	0
Weighted Average Useful Life (Years)	12 years
Patents & Trademarks [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	6.4	6.4
Accumulated Amortization	4.0	3.7
Weighted Average Useful Life (Years)	17 years
Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	4.4	0
Accumulated Amortization	0.1	0
Weighted Average Useful Life (Years)	30 years
Customer Lists [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2.9	2.9
Accumulated Amortization	2.7	2.6
Weighted Average Useful Life (Years)	15 years
Specialty Minerals [Member]
Goodwill [Roll Forward]
Balance Beginning	14.3	14.1
Change in goodwill relating to [Abstract]
Acquisition	0
Foreign exchange translation	(0.6)	0.2
Total	(0.6)	0.2
Balance Ending	13.7	14.3
Refractories [Member]
Goodwill [Roll Forward]
Balance Beginning	50.1	51.7
Change in goodwill relating to [Abstract]
Acquisition	0
Foreign exchange translation	(1.1)	(1.6)
Total	(1.1)	(1.6)
Balance Ending	49.0	50.1
Performance Materials [Member]
Goodwill [Roll Forward]
Balance Beginning	0	0
Change in goodwill relating to [Abstract]
Acquisition	453.2
Foreign exchange translation	0	0
Total	453.2	0
Balance Ending	453.2	0
Construction Technologies [Member]
Goodwill [Roll Forward]
Balance Beginning	0	0
Change in goodwill relating to [Abstract]
Acquisition	255.0
Foreign exchange translation	0	0
Total	255.0	0
Balance Ending	$ 255.0	$ 0

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Accumulated amount of amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

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-Publisher FASB

-Name Accounting Standards Codification

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Amount of increase (decrease) from foreign currency translation adjustments of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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