Earnings Per Share (EPS) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 28, 2015	Jun. 29, 2014	Jun. 28, 2015	Jun. 29, 2014
Amounts attributable to MTI [Abstract]
Income from continuing operations	$ 26.6	$ 16.7	$ 61.7	$ 32.3
Income from discontinued operations	0.0	1.8	0.0	1.8
Net income attributable to Minerals Technologies Inc. (MTI)	$ 26.6	$ 18.5	$ 61.7	$ 34.1
Weighted average shares outstanding (in shares)	34,700,000	34,500,000	34,700,000	34,500,000
Earnings per share attributable to MTI [Abstract]
Continuing operations (in dollars per share)	$ 0.77	$ 0.48	$ 1.78	$ 0.94
Discontinued operations (in dollars per share)	0	0.05	0	0.05
Basic earnings per share attributable to MTI (in dollars per share)	$ 0.77	$ 0.53	$ 1.78	$ 0.99
Amounts attributable to MTI [Abstract]
Income from continuing operations	$ 26.6	$ 16.7	$ 61.7	$ 32.3
Income from discontinued operations	0.0	1.8	0.0	1.8
Net income attributable to Minerals Technologies Inc. (MTI)	$ 26.6	$ 18.5	$ 61.7	$ 34.1
Weighted average shares outstanding (in shares)	34,700,000	34,500,000	34,700,000	34,500,000
Dilutive effect of stock options and stock units (in shares)	300,000	300,000	300,000	200,000
Weighted average shares outstanding, adjusted (in shares)	35,000,000	34,800,000	35,000,000	34,700,000
Earnings per share attributable to MTI [Abstract]
Continuing operations (in dollars per share)	$ 0.76	$ 0.48	$ 1.76	$ 0.93
Discontinued operations (in dollars per share)	0	0.05	0	0.05
Diluted earnings per share attributable to MTI (in dollars per share)	$ 0.76	$ 0.53	$ 1.76	$ 0.98
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not included in the weighted average commons shares outstanding calculation (in shares)	238,505	173,068	238,505	173,068