CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
Consolidated net income	$ 173.2	$ 199.0	$ 137.1
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(67.9)	44.7	(40.2)
Pension and postretirement plan adjustments	16.9	(8.5)	(3.2)
Unrealized gains on cash flow hedges	1.6	0.3	1.6
Total other comprehensive income (loss), net of tax	(49.4)	36.5	(41.8)
Total comprehensive income including non-controlling interests	123.8	235.5	95.3
Less: Net income attributable to non-controlling interests	4.2	3.9	3.7
Less: Foreign currency translation adjustments attributable to non-controlling interests	(1.8)	1.5	(1.6)
Comprehensive income attributable to non-controlling interests	2.4	5.4	2.1
Comprehensive income attributable to Minerals Technologies Inc.	$ 121.4	$ 230.1	$ 93.2