CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statements of Income [Abstract]
Total net sales	$ 1,791.0	$ 1,807.6	$ 1,675.7
Total cost of sales	1,350.4	1,346.2	1,208.5
Production margin	440.6	461.4	467.2
Marketing and administrative expenses	187.5	178.6	180.7
Research and development expenses	20.3	22.7	23.7
Acquisition-related transaction and integration costs	0.0	1.7	3.4
Litigation expenses	10.9	0.0	0.0
Restructuring and other items, net	13.2	2.5	15.0
Income from operations	208.7	255.9	244.4
Interest expense, net	(43.2)	(45.9)	(43.4)
Debt modification costs and fees	0.0	0.0	(3.9)
Non-cash pension settlement charge	0.0	(4.4)	0.0
Other non-operating income (deductions), net	(8.2)	(1.5)	(6.2)
Total non-operating deductions, net	(51.4)	(51.8)	(53.5)
Income from operations before tax and equity in earnings	157.3	204.1	190.9
Provision (benefit) for taxes on income	22.8	34.4	(6.6)
Equity in earnings of affiliates, net of tax	1.9	3.5	1.5
Consolidated net income	136.4	173.2	199.0
Less: Net income attributable to non-controlling interests	3.7	4.2	3.9
Net income attributable to Minerals Technologies Inc. (MTI)	$ 132.7	$ 169.0	$ 195.1
Basic:
Income from operations attributable to MTI (in dollars per share)	$ 3.79	$ 4.79	$ 5.54
Diluted:
Income from operations attributable to MTI (in dollars per share)	3.78	4.75	5.48
Cash dividends declared per common share (in dollars per share)	$ 0.20	$ 0.20	$ 0.20
Shares used in computation of earnings per share:
Basic (in shares)	35.0	35.3	35.2
Diluted (in shares)	35.1	35.6	35.6
Product [Member]
Statements of Income [Abstract]
Total net sales	$ 1,695.8	$ 1,729.3	$ 1,599.0
Total cost of sales	1,285.8	1,293.3	1,158.5
Service [Member]
Statements of Income [Abstract]
Total net sales	95.2	78.3	76.7
Total cost of sales	$ 64.6	$ 52.9	$ 50.0