Restructuring and Other Items, net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Annualized savings from reduction of workforce	$ 11.5		$ 29.0
Gain on previously impaired assets	2.9
Reduction in workforce			10.00%
Restructuring and Other Charges [Abstract]
Impairment of Assets	18.5	$ 34.2	$ 23.7
Severance and other employee costs	12.7	11.0	18.8
Total restructuring and other items, net	28.3	45.2	43.2
Restructuring Reserve [Roll Forward]
Restructuring liability, beginning of period	7.9
Additional provisions	12.7
Cash payments	(17.0)
Restructuring liability, ending of period	3.6	7.9
Specialty Minerals [Member]
Restructuring and Other Charges [Abstract]
Severance and other employee costs	0.0	0.0	3.0
Refractories [Member]
Restructuring Cost and Reserve [Line Items]
Gain on previously impaired assets	2.9
Restructuring and Other Charges [Abstract]
Severance and other employee costs	0.0	2.0	0.7
Other	(2.9)	0.0	0.0
Performance Materials [Member]
Restructuring and Other Charges [Abstract]
Impairment of Assets	0.0	0.0	0.4
Severance and other employee costs	0.0	0.0	5.6
Other	0.0	0.0	0.7
Construction Technologies [Member]
Restructuring and Other Charges [Abstract]
Impairment of Assets	0.0	0.0	11.7
Severance and other employee costs	0.0	0.0	5.8
Energy Services [Member]
Restructuring and Other Charges [Abstract]
Impairment of Assets	18.5	33.0	11.6
Severance and other employee costs	12.7	9.0	3.7
Corporate [Member]
Restructuring and Other Charges [Abstract]
Impairment of Assets	$ 0.0	$ 1.2	$ 0.0