CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 28, 2020	Jun. 30, 2019	Jun. 28, 2020	Jun. 30, 2019
Statements of Income [Abstract]
Total net sales	$ 357.2	$ 463.8	$ 774.7	$ 901.5
Total cost of sales	268.3	351.8	579.0	679.8
Production margin	88.9	112.0	195.7	221.7
Marketing and administrative expenses	41.8	48.4	85.2	91.3
Research and development expenses	5.1	4.9	10.2	9.7
Litigation expenses	8.3	0.0	8.9	0.0
Restructuring and other items, net	6.5	13.2	6.5	13.2
Income from operations	27.2	45.5	84.9	107.5
Interest expense, net	(8.1)	(10.9)	(17.4)	(22.3)
Non-cash pension settlement charge	(4.3)	0.0	(4.3)	0.0
Other non-operating income (deductions), net	(0.2)	(2.4)	0.4	(3.8)
Total non-operating deductions, net	(12.6)	(13.3)	(21.3)	(26.1)
Income from operations before tax and equity in earnings	14.6	32.2	63.6	81.4
Provision for taxes on income	0.9	5.1	10.6	14.4
Equity in earnings of affiliates, net of tax	1.2	0.5	1.5	0.6
Consolidated net income	14.9	27.6	54.5	67.6
Less: Net income attributable to non-controlling interests	0.5	1.0	1.5	1.9
Net income attributable to Minerals Technologies Inc.	$ 14.4	$ 26.6	$ 53.0	$ 65.7
Basic:
Income from operations attributable to Minerals Technologies Inc. (in dollars per share)	$ 0.42	$ 0.76	$ 1.55	$ 1.87
Diluted:
Income from operations attributable to Minerals Technologies Inc. (in dollars per share)	0.42	0.75	1.55	1.86
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)	34.1	35.2	34.2	35.2
Diluted (in shares)	34.1	35.3	34.3	35.3
Product [Member]
Statements of Income [Abstract]
Total net sales	$ 339.5	$ 438.0	$ 731.8	$ 855.4
Total cost of sales	256.6	334.0	550.7	648.0
Service [Member]
Statements of Income [Abstract]
Total net sales	17.7	25.8	42.9	46.1
Total cost of sales	$ 11.7	$ 17.8	$ 28.3	$ 31.8