Earnings Per Share (EPS) (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2014	Sep. 29, 2013	Sep. 28, 2014	Sep. 29, 2013
Basic EPS [Abstract]
Income from continuing operations attributable to MTI	$ 36.8	$ 21.9	$ 69.1	$ 63.4
Income (loss) from discontinued operations attributable to MTI	0.2	0	2.0	(5.7)
Net income attributable to Minerals Technologies Inc. (MTI)	37.0	21.9	71.1	57.7
Weighted average shares outstanding (in shares)	34,500,000	34,600,000	34,500,000	34,800,000
Basic earnings per share from continuing operations attributable to MTI (in dollars per share)	$ 1.07	$ 0.63	$ 2.00	$ 1.82
Basic earnings (loss) per share from discontinued operations attributable to MTI (in dollars per share)	$ 0	$ 0	$ 0.06	$ (0.16)
Basic earnings per share attributable to MTI (in dollars per share)	$ 1.07	$ 0.63	$ 2.06	$ 1.66
Diluted EPS [Abstract]
Income from continuing operations attributable to MTI	36.8	21.9	69.1	63.4
Income (loss) from discontinued operations attributable to MTI	0.2	0	2.0	(5.7)
Net income attributable to Minerals Technologies Inc. (MTI)	$ 37.0	$ 21.9	$ 71.1	$ 57.7
Weighted average shares outstanding (in shares)	34,500,000	34,600,000	34,500,000	34,800,000
Dilutive effect of stock options and stock units (in shares)	300,000	300,000	300,000	300,000
Weighted average shares outstanding, adjusted (in shares)	34,800,000	34,900,000	34,800,000	35,100,000
Diluted earnings per share from continuing operations attributable to MTI (in dollars per share)	$ 1.06	$ 0.63	$ 1.99	$ 1.81
Diluted earnings (loss) per share from discontinued operations attributable to MTI (in dollars per share)	$ 0	$ 0	$ 0.06	$ (0.16)
Diluted earnings per share attributable to MTI (in dollars per share)	$ 1.06	$ 0.63	$ 2.05	$ 1.65
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)	173,068	238,287	173,068	238,287