CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
CONSOLIDATED STATEMENTS OF INCOME [Abstract]
Product sales	$ 1,599.0	$ 1,552.1	$ 1,615.4
Service revenue	76.7	85.9	182.2
Total net sales	1,675.7	1,638.0	1,797.6
Cost of goods sold	1,158.5	1,117.7	1,190.0
Cost of service revenue	50.0	59.9	136.6
Total cost of sales	1,208.5	1,177.6	1,326.6
Production margin	467.2	460.4	471.0
Marketing and administrative expenses	182.4	179.4	190.1
Research and development expenses	23.7	23.8	23.6
Acquisition related transaction and integration costs	3.4	8.0	11.8
Restructuring and other items, net	15.0	28.3	45.2
Income from operations	242.7	220.9	200.3
Interest expense, net	(43.4)	(54.4)	(60.9)
Extinguishment of debt costs and fees	(3.9)	0.0	(4.5)
Other non-operating income (deductions), net	(4.5)	3.8	(2.3)
Total non-operating deductions, net	(51.8)	(50.6)	(67.7)
Income from operations before provision for taxes and equity in earnings	190.9	170.3	132.6
Provision (benefit) for taxes on income	(6.6)	35.3	22.8
Equity in earnings of affiliates, net of tax	1.5	2.1	1.8
Consolidated net income	199.0	137.1	111.6
Less: Net income attributable to non-controlling interests	3.9	3.7	3.7
Net income attributable to Minerals Technologies Inc. (MTI)	$ 195.1	$ 133.4	$ 107.9
Basic:
Income from operations attributable to MTI (in dollars per share)	$ 5.54	$ 3.82	$ 3.11
Diluted:
Income from operations attributable to MTI (in dollars per share)	5.48	3.79	3.08
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)	35.2	34.9	34.7
Diluted (in shares)	35.6	35.2	35.0