CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 29, 2025	Jun. 30, 2024	Jun. 29, 2025	Jun. 30, 2024
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) [Abstract]
Net income (loss)	$ 46.3	$ 20.9	$ (96.7)	$ 68.5
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	30.0	(9.9)	39.8	(34.3)
Pension and postretirement plan adjustments	0.1	0.2	0.2	0.5
Unrealized gains (losses) on derivative instruments	0.0	0.1	(0.2)	1.5
Total other comprehensive income (loss), net of tax	30.1	(9.6)	39.8	(32.3)
Total comprehensive income (loss) including non-controlling interests	76.4	11.3	(56.9)	36.2
Comprehensive income attributable to non-controlling interests	1.2	0.4	1.5	0.6
Comprehensive income (loss) attributable to Minerals Technologies Inc.	$ 75.2	$ 10.9	$ (58.4)	$ 35.6