Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended
	Mar. 29, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (7.2)	$ 0.4
Other comprehensive income (loss):
Change in cumulative translation adjustment, net of tax	(4.4)	(2.1)
Change in pension net actuarial gain, net of tax	0.0	0.2
Change in fair value of derivatives, net of tax	0.0	0.2
Other comprehensive loss	(4.4)	(1.7)
Comprehensive loss	(11.6)	(1.3)
Comprehensive income (loss), attributable to noncontrolling interests	(0.1)	5.2
Comprehensive loss attributable to UCT	$ (11.5)	$ (6.5)