Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Shares [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total stockholders' Equity of UCT [Member]	Noncontrolling Interests [Member]
Beginning balance at Dec. 25, 2020	$ 551.2	$ 0.1	$ 312.8	$ (3.3)	$ 217.9	$ 5.1	$ 532.6	$ 18.6
Beginning balance, Shares at Dec. 25, 2020		40,600,000		600,000
Issuance of common stock in public offering	192.8		192.8				192.8
Issuance of common stock in public offering, Shares		3,700,000
Issuance under employee stock plans	0.3		0.3				0.3
Issuance under employee stock plans, Shares		700,000
Employees’ taxes paid upon vesting of restricted stock units	(7.0)		(7.0)				(7.0)
Employees' taxes paid upon vesting of restricted stock units, Shares		(100,000)
Stock-based compensation expense	11.5		11.5				11.5
Noncontrolling interests from acquisition of Ham-let	1.8							1.8
Net income	77.6				74.0		74.0	3.6
Dividend payments to a joint venture shareholder	(0.1)							(0.1)
Reclassification of common stock purchase obligation liability upon modification of agreement (see Note 11)	16.4							16.4
Other comprehensive loss	(4.2)					(4.2)	(4.2)
Ending balance at Sep. 24, 2021	840.3	$ 0.1	510.4	$ (3.3)	291.9	0.9	800.0	40.3
Ending balance, Shares at Sep. 24, 2021		44,900,000		600,000
Beginning balance at Jun. 25, 2021	788.7	$ 0.1	506.1	$ (3.3)	260.0	4.6	767.5	21.2
Beginning balance, Shares at Jun. 25, 2021		44,800,000		600,000
Issuance under employee stock plans, Shares		100,000
Stock-based compensation expense	4.3		4.3				4.3
Noncontrolling interests from acquisition of Ham-let	0.6							0.6
Net income	34.0				31.9		31.9	2.1
Reclassification of common stock purchase obligation liability upon modification of agreement (see Note 11)	16.4							16.4
Other comprehensive loss	(3.7)					(3.7)	(3.7)
Ending balance at Sep. 24, 2021	840.3	$ 0.1	510.4	$ (3.3)	291.9	0.9	800.0	40.3
Ending balance, Shares at Sep. 24, 2021		44,900,000		600,000
Beginning balance at Dec. 31, 2021	892.7	$ 0.1	514.9	$ (3.3)	337.4	(0.2)	848.9	43.8
Beginning balance, Shares at Dec. 31, 2021		44,900,000		600,000
Issuance under employee stock plans	0.7		0.7				0.7
Issuance under employee stock plans, Shares		600,000
Employees’ taxes paid upon vesting of restricted stock units	(3.9)		(3.9)				(3.9)
Employees' taxes paid upon vesting of restricted stock units, Shares		(100,000)
Stock-based compensation expense	14.8		14.8				14.8
Net income	22.0				12.5		12.5	9.5
Dividend payments to a joint venture shareholder	(0.2)							(0.2)
Other comprehensive loss	(24.0)					(16.3)	(16.3)	(7.7)
Ending balance at Sep. 30, 2022	902.1	$ 0.1	526.5	$ (3.3)	349.9	(16.5)	856.7	45.4
Ending balance, Shares at Sep. 30, 2022		45,400,000		600,000
Beginning balance at Jul. 01, 2022	895.5	$ 0.1	521.9	$ (3,300.0)	340,200.0	(13,300.0)	845,600.0	49,900.0
Beginning balance, Shares at Jul. 01, 2022		45,400,000		600,000
Employees’ taxes paid upon vesting of restricted stock units	(0.1)		(0.1)				(0.1)
Stock-based compensation expense	4.7		4.7				4.7
Net income	12.9				9.7		9.7	3.2
Other comprehensive loss	(10.9)					(3.2)	(3.2)	(7.7)
Ending balance at Sep. 30, 2022	$ 902.1	$ 0.1	$ 526.5	$ (3.3)	$ 349.9	$ (16.5)	$ 856.7	$ 45.4
Ending balance, Shares at Sep. 30, 2022		45,400,000		600,000