Condensed Consolidated Statements of Stockholders' Equity - USD ($) shares in Millions, $ in Millions	Total	Total Stockholders’ Equity of UCT	Common Stock	Additional Paid-in Capital	Treasury shares	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests
Common stock, shares, beginning balance (in shares) at Dec. 29, 2023			44.6
Treasury stock, shares, beginning balance (in shares) at Dec. 29, 2023					1.5
Beginning balance at Dec. 29, 2023	$ 897.2	$ 838.9	$ 0.1	$ 541.5	$ (45.0)	$ 346.7	$ (4.4)	$ 58.3
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	3.5	3.5		3.5
Net income (loss)	(7.2)	(9.4)				(9.4)		2.2
Other comprehensive loss	(4.4)	(2.1)					(2.1)	(2.3)
Ending balance at Mar. 29, 2024	$ 889.1	830.9	$ 0.1	545.0	$ (45.0)	337.3	(6.5)	58.2
Common stock, shares, ending balance (in shares) at Mar. 29, 2024			44.6
Treasury stock, shares, ending balance (in shares) at Mar. 29, 2024					1.5
Common stock, shares, beginning balance (in shares) at Dec. 27, 2024	45.1		45.1
Treasury stock, shares, beginning balance (in shares) at Dec. 27, 2024	1.5				1.5
Beginning balance at Dec. 27, 2024	$ 935.8	873.6	$ 0.1	558.4	$ (45.0)	370.4	(10.3)	62.2
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	2.9	2.9		2.9
Net income (loss)	(2.5)	(5.0)				(5.0)		2.5
Other comprehensive loss	0.6	0.5					0.5	0.1
Ending balance at Mar. 28, 2025	$ 936.8	$ 872.0	$ 0.1	$ 561.3	$ (45.0)	$ 365.4	$ (9.8)	$ 64.8
Common stock, shares, ending balance (in shares) at Mar. 28, 2025	45.1		45.1
Treasury stock, shares, ending balance (in shares) at Mar. 28, 2025	1.5				1.5