CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 29, 2024	Oct. 01, 2023	Sep. 29, 2024	Oct. 01, 2023
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) [Abstract]
Net income (loss)	$ 47.7	$ (18.1)	$ 116.2	$ 47.6
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	24.7	(22.1)	(9.7)	(38.2)
Pension and postretirement plan adjustments	0.2	0.4	0.7	1.3
Unrealized gains (losses) on derivative instruments	(2.1)	0.7	(0.6)	(1.2)
Total other comprehensive income (loss), net of tax	22.8	(21.0)	(9.6)	(38.1)
Total comprehensive income (loss) including non-controlling interests	70.5	(39.1)	106.6	9.5
Comprehensive (income) loss attributable to non-controlling interests	(4.6)	0.5	(5.1)	(0.8)
Comprehensive income (loss) attributable to Minerals Technologies Inc.	$ 65.9	$ (38.6)	$ 101.5	$ 8.7