CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Oct. 01, 2017	Oct. 02, 2016	Oct. 01, 2017	Oct. 02, 2016
CONDENSED CONSOLIDATED STATEMENTS OF INCOME (Unaudited) [Abstract]
Product sales	$ 405.4	$ 379.7	$ 1,187.9	$ 1,171.1
Service revenue	19.0	19.8	55.6	65.6
Total net sales	424.4	399.5	1,243.5	1,236.7
Cost of goods sold	293.0	272.0	854.7	840.8
Cost of service revenue	12.2	12.3	36.2	46.9
Total cost of sales	305.2	284.3	890.9	887.7
Production margin	119.2	115.2	352.6	349.0
Marketing and administrative expenses	45.6	42.4	134.1	134.2
Research and development expenses	5.9	5.9	17.8	17.9
Acquisition related transaction and integration costs	0.5	1.9	2.8	5.1
Restructuring and other items, net	0.4	(2.3)	0.9	27.4
Income from operations	66.8	67.3	197.0	164.4
Interest expense, net	(10.5)	(13.4)	(32.5)	(41.4)
Debt modification costs and fees	0.0	0.0	(3.9)	0.0
Other non-operating income (deductions), net	(1.7)	(0.6)	(3.4)	1.7
Total non-operating deductions, net	(12.2)	(14.0)	(39.8)	(39.7)
Income from continuing operations before provision for taxes and equity in earnings	54.6	53.3	157.2	124.7
Provision for taxes on income	12.1	11.5	35.6	26.7
Equity in earnings of affiliates, net of tax	0.4	0.7	0.7	1.6
Consolidated net income	42.9	42.5	122.3	99.6
Less: Net income attributable to non-controlling interests	1.2	0.9	3.0	2.9
Net income attributable to Minerals Technologies Inc. (MTI)	$ 41.7	$ 41.6	$ 119.3	$ 96.7
Basic:
Income from continuing operations attributable to MTI (in dollars per share)	$ 1.18	$ 1.19	$ 3.40	$ 2.78
Diluted:
Income from continuing operations attributable to MTI (in dollars per share)	1.17	1.18	3.35	2.75
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)	35.3	34.9	35.1	34.8
Diluted (in shares)	35.6	35.3	35.6	35.1