Earnings (Loss) per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2025	Jun. 30, 2024	Jun. 29, 2025	Jun. 30, 2024
Earnings (Loss) per Share [Abstract]
Net income (loss) attributable to Minerals Technologies Inc.	$ 45.4	$ 19.7	$ (98.6)	$ 66.4
Weighted average shares outstanding (in shares)	31,600,000	32,200,000	31,700,000	32,300,000
Dilutive effect of stock options and deferred restricted stock units (in shares)	0	200,000	0	100,000
Weighted average shares outstanding, adjusted (in shares)	31,600,000	32,400,000	31,700,000	32,400,000
Basic earnings (loss) per share attributable to Minerals Technologies Inc. (in dollars per share)	$ 1.44	$ 0.61	$ (3.11)	$ 2.06
Diluted earnings (loss) per share attributable to Minerals Technologies Inc. (in dollars per share)	$ 1.44	$ 0.61	$ (3.11)	$ 2.05
Stock Options [Member]
Earnings (Loss) per Share [Abstract]
Options outstanding (in shares)	1,594,166	1,482,563	1,594,166	1,482,563
Anti-dilutive securities not included in computation of diluted earnings per share (in shares)	1,387,282	196,471	1,387,282	196,471