Earnings per Share (EPS) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 29, 2020	Mar. 31, 2019
Earnings per Share (EPS) [Abstract]
Net income attributable to Minerals Technologies Inc.	$ 38.6	$ 39.1
Weighted average shares outstanding (in shares)	34,400,000	35,200,000
Dilutive effect of stock options and stock units (in shares)	0	100,000
Weighted average shares outstanding, adjusted (in shares)	34,400,000	35,300,000
Basic earnings per share attributable to Minerals Technologies Inc. (in dollars per share)	$ 1.12	$ 1.11
Diluted earnings per share attributable to Minerals Technologies Inc. (in dollars per share)	$ 1.12	$ 1.11
Stock Options [Member]
Antidilutive Securities Excluded from Earnings Per Share Calculation [Abstract]
Anti-dilutive securities not included in the weighted average commons shares outstanding calculation (in shares)	1,181,945	748,754