Condensed Consolidated Statements of Comprehensive Income (LOSS) - USD ($) $ in Millions	3 Months Ended
	Mar. 27, 2020	Mar. 29, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 10.5	$ 1.4
Other comprehensive income (loss):
Change in cumulative translation adjustment	(3.2)	(0.9)
Change in defined benefit pension plan net actuarial loss	(0.1)
Total other comprehensive loss	(3.3)	(0.9)
Other comprehensive income, attributable to noncontrolling interests	1.1	0.8
Comprehensive income (loss) attributable to UCT	$ 6.1	$ (0.3)