CONDENSED CONSOLIDATED STATEMENTS OF INCOME (LOSS) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2025	Jun. 30, 2024	Jun. 29, 2025	Jun. 30, 2024
CONDENSED CONSOLIDATED STATEMENTS OF INCOME (LOSS) [Abstract]
Net sales	$ 528.9	$ 541.2	$ 1,020.7	$ 1,075.7
Cost of goods sold	392.0	397.3	764.2	795.9
Production margin	136.9	143.9	256.5	279.8
Marketing and administrative expenses	52.2	53.3	102.8	106.3
Research and development expenses	5.7	5.8	11.5	11.4
Provision for litigation reserve and credit losses	0.0	30.0	215.0	30.0
Restructuring and other items	5.8	0.0	11.3	0.0
Gain on sale of assets, net	(5.6)	0.0	(5.6)	0.0
Litigation expenses	4.2	4.2	7.0	6.3
Income (loss) from operations	74.6	50.6	(85.5)	125.8
Interest expense, net	(13.6)	(14.9)	(27.8)	(29.8)
Other non-operating deductions, net	(1.9)	(1.1)	(3.9)	(1.3)
Total non-operating deductions, net	(15.5)	(16.0)	(31.7)	(31.1)
Income (loss) before tax and equity in earnings	59.1	34.6	(117.2)	94.7
Provision (benefit) for taxes on income	13.9	15.6	(18.2)	29.5
Equity in earnings of affiliates, net of tax	1.1	1.9	2.3	3.3
Net income (loss)	46.3	20.9	(96.7)	68.5
Less: Net income attributable to non-controlling interests	0.9	1.2	1.9	2.1
Net income (loss) attributable to Minerals Technologies Inc.	$ 45.4	$ 19.7	$ (98.6)	$ 66.4
Earnings (loss) per share:
Basic net income (loss) attributable to Minerals Technologies Inc. (in dollars per share)	$ 1.44	$ 0.61	$ (3.11)	$ 2.06
Diluted net income (loss) attributable to Minerals Technologies Inc. (in dollars per share)	1.44	0.61	(3.11)	2.05
Cash dividends declared per common share (in dollars per share)	$ 0.11	$ 0.1	$ 0.22	$ 0.2
Shares used in computation of earnings per share:
Basic (in shares)	31.6	32.2	31.7	32.3
Diluted (in shares)	31.6	32.4	31.7	32.4