CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 29, 2019	Sep. 30, 2018	Sep. 29, 2019	Sep. 30, 2018
Statements of Income [Abstract]
Total net sales	$ 449.3	$ 464.1	$ 1,350.8	$ 1,360.1
Total cost of sales	338.1	344.9	1,017.9	1,011.5
Production margin	111.2	119.2	332.9	348.6
Marketing and administrative expenses	46.9	45.4	138.2	135.1
Research and development expenses	5.2	5.0	14.9	17.5
Acquisition related transaction and integration costs	0.0	0.3	0.0	1.7
Litigation expenses	5.6	0.0	5.6	0.0
Restructuring and other items, net	0.0	0.3	13.2	0.7
Income from operations	53.5	68.2	161.0	193.6
Interest expense, net	(11.0)	(11.7)	(33.3)	(33.9)
Non-cash pension settlement charge	0.0	(3.6)	0.0	(3.6)
Other non-operating income (deductions), net	(1.6)	(0.9)	(5.4)	(0.5)
Total non-operating deductions, net	(12.6)	(16.2)	(38.7)	(38.0)
Income from operations before tax and equity in earnings	40.9	52.0	122.3	155.6
Provision for taxes on income	2.6	9.7	17.0	29.3
Equity in earnings of affiliates, net of tax	0.8	0.6	1.4	2.9
Consolidated net income	39.1	42.9	106.7	129.2
Less: Net income attributable to non-controlling interests	1.1	1.0	3.0	3.3
Net income attributable to Minerals Technologies Inc.	$ 38.0	$ 41.9	$ 103.7	$ 125.9
Basic:
Income from operations attributable to Minerals Technologies Inc. (in dollars per share)	$ 1.09	$ 1.19	$ 2.95	$ 3.57
Diluted:
Income from operations attributable to Minerals Technologies Inc. (in dollars per share)	1.08	1.18	2.95	3.54
Cash dividends declared per common share (in dollars per share)	$ 0.05	$ 0.05	$ 0.15	$ 0.15
Shares used in computation of earnings per share:
Basic (in shares)	35.0	35.3	35.1	35.3
Diluted (in shares)	35.1	35.6	35.2	35.6
Product [Member]
Statements of Income [Abstract]
Total net sales	$ 423.8	$ 444.9	$ 1,279.2	$ 1,302.1
Total cost of sales	320.5	332.1	968.5	972.4
Service [Member]
Statements of Income [Abstract]
Total net sales	25.5	19.2	71.6	58.0
Total cost of sales	$ 17.6	$ 12.8	$ 49.4	$ 39.1