CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Statements of Income [Abstract]
Net sales	$ 388.3	$ 449.3	$ 1,163.0	$ 1,350.8
Cost of sales	289.9	338.1	868.9	1,017.9
Production margin	98.4	111.2	294.1	332.9
Marketing and administrative expenses	42.1	46.9	127.3	138.2
Research and development expenses	4.8	5.2	15.0	14.9
Litigation expenses	1.5	5.6	10.4	5.6
Restructuring and other items, net	1.5	0.0	8.0	13.2
Income from operations	48.5	53.5	133.4	161.0
Interest expense, net	(10.1)	(11.0)	(27.5)	(33.3)
Non-cash pension settlement charge	(1.1)	0.0	(5.4)	0.0
Other non-operating deductions, net	(1.5)	(1.6)	(1.1)	(5.4)
Total non-operating deductions, net	(12.7)	(12.6)	(34.0)	(38.7)
Income from operations before tax and equity in earnings	35.8	40.9	99.4	122.3
Provision for taxes on income	7.0	2.6	17.6	17.0
Equity in earnings of affiliates, net of tax	0.5	0.8	2.0	1.4
Consolidated net income	29.3	39.1	83.8	106.7
Less: Net income attributable to non-controlling interests	1.0	1.1	2.5	3.0
Net income attributable to Minerals Technologies Inc.	$ 28.3	$ 38.0	$ 81.3	$ 103.7
Basic:
Income from operations attributable to Minerals Technologies Inc. (in dollars per share)	$ 0.83	$ 1.09	$ 2.38	$ 2.95
Diluted:
Income from operations attributable to Minerals Technologies Inc. (in dollars per share)	0.83	1.08	2.38	2.95
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)	34.1	35.0	34.2	35.1
Diluted (in shares)	34.1	35.1	34.2	35.2
Product [Member]
Statements of Income [Abstract]
Net sales	$ 375.0	$ 423.8	$ 1,106.8	$ 1,279.2
Cost of sales	280.9	320.5	831.6	968.5
Service [Member]
Statements of Income [Abstract]
Net sales	13.3	25.5	56.2	71.6
Cost of sales	$ 9.0	$ 17.6	$ 37.3	$ 49.4