CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 28, 2025	Sep. 29, 2024	Sep. 28, 2025	Sep. 29, 2024
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) [Abstract]
Net income (loss)	$ 44.2	$ 47.7	$ (52.5)	$ 116.2
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(5.0)	24.7	34.8	(9.7)
Pension and postretirement plan adjustments	0.1	0.2	0.3	0.7
Unrealized losses on derivative instruments	(0.1)	(2.1)	(0.3)	(0.6)
Total other comprehensive income (loss), net of tax	(5.0)	22.8	34.8	(9.6)
Total comprehensive income (loss) including non-controlling interests	39.2	70.5	(17.7)	106.6
Comprehensive income attributable to non-controlling interests	0.8	4.6	2.2	5.1
Comprehensive income (loss) attributable to Minerals Technologies Inc.	$ 38.4	$ 65.9	$ (19.9)	$ 101.5