Earnings (Loss) per Share - Computation of Basic and Diluted Earnings (Loss) per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 28, 2025	Sep. 29, 2024	Sep. 28, 2025	Sep. 29, 2024
Earnings (Loss) per Share [Abstract]
Net income (loss) attributable to Minerals Technologies Inc. (in Dollars)	$ 43.0	$ 46.7	$ (55.6)	$ 113.1
Weighted average shares outstanding (in Shares)	31.3	32.1	31.6	32.2
Dilutive effect of stock options and deferred restricted stock units (in Shares)		0.2		0.2
Weighted average shares outstanding, adjusted (in Shares)	31.3	32.3	31.6	32.4
Basic earnings (loss) per share attributable to Minerals Technologies Inc. (in Dollars per share)	$ 1.37	$ 1.45	$ (1.76)	$ 3.51
Diluted earnings (loss) per share attributable to Minerals Technologies Inc. (in Dollars per share)	$ 1.37	$ 1.45	$ (1.76)	$ 3.49