CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	3 Months Ended
	Apr. 05, 2026	Mar. 30, 2025
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) [Abstract]
Net income (loss)	$ 37.3	$ (143.0)
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	(13.4)	9.9
Pension and postretirement plan adjustments	0.0	0.1
Unrealized gain (loss) on derivative instruments	0.1	(0.3)
Total other comprehensive income (loss), net of tax	(13.3)	9.7
Total comprehensive income (loss) including non-controlling interests	24.0	(133.3)
Comprehensive income attributable to non-controlling interests	1.0	0.4
Comprehensive income (loss) attributable to Minerals Technologies Inc.	$ 23.0	$ (133.7)