CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jul. 04, 2021	Jun. 28, 2020	Jul. 04, 2021	Jun. 28, 2020
Statements of Income [Abstract]
Net sales	$ 455.6	$ 357.2	$ 908.2	$ 774.7
Cost of goods sold	340.2	268.3	681.0	579.0
Production margin	115.4	88.9	227.2	195.7
Marketing and administrative expenses	46.4	41.8	94.4	85.2
Research and development expenses	4.9	5.1	9.9	10.2
Acquisition-related expenses	0.4	0.0	0.4	0.0
Litigation expenses	0.0	8.3	0.0	8.9
Restructuring and other items, net	0.0	6.5	0.0	6.5
Income from operations	63.7	27.2	122.5	84.9
Interest expense, net	(9.1)	(8.1)	(19.0)	(17.4)
Non-cash pension settlement charge	(2.2)	(4.3)	(2.2)	(4.3)
Other non-operating income (deductions), net	(0.1)	(0.2)	0.4	0.4
Total non-operating deductions, net	(11.4)	(12.6)	(20.8)	(21.3)
Income from operations before tax and equity in earnings	52.3	14.6	101.7	63.6
Provision for taxes on income	9.8	0.9	18.7	10.6
Equity in earnings of affiliates, net of tax	0.5	1.2	1.0	1.5
Consolidated net income	43.0	14.9	84.0	54.5
Less: Net income attributable to non-controlling interests	1.1	0.5	2.2	1.5
Net income attributable to Minerals Technologies Inc.	$ 41.9	$ 14.4	$ 81.8	$ 53.0
Basic:
Income from operations attributable to Minerals Technologies Inc. (in dollars per share)	$ 1.24	$ 0.42	$ 2.42	$ 1.55
Diluted:
Income from operations attributable to Minerals Technologies Inc. (in dollars per share)	1.23	0.42	2.41	1.55
Cash dividends declared per common share (in dollars per share)	$ 0.05	$ 0.05	$ 0.10	$ 0.10
Shares used in computation of earnings per share:
Basic (in shares)	33.7	34.1	33.8	34.2
Diluted (in shares)	34.1	34.1	34.0	34.3