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 stock holder's Equity of UCT [Member]	Noncontrolling Interests [Member]
Beginning balance at Dec. 28, 2018	$ 451.0	$ 0.1	$ 290.4	$ (3.3)	$ 149.7	$ (0.6)	$ 436.3	$ 14.7
Beginning balance, Shares at Dec. 28, 2018		39,100,000		600,000
Issuance under employee stock plans	0.3		0.3				0.3
Issuance under employee stock plans, Shares		900,000
Stock-based compensation expense	12.1		12.1				12.1
Employees’ taxes paid upon vesting of restricted stock units	(1.9)		(1.9)				(1.9)
Employees' taxes paid upon vesting of restricted stock units, Shares		(100,000)
Net income (loss)	(7.7)				(9.4)		(9.4)	1.7
Dividend payments to a joint venture shareholder	(0.6)							(0.6)
Other comprehensive income (loss)	(0.7)					(0.7)	(0.7)
Ending balance at Dec. 27, 2019	452.5	$ 0.1	300.9	$ (3.3)	140.3	(1.3)	436.7	15.8
Ending balance, Shares at Dec. 27, 2019		39,900,000		600,000
Issuance under employee stock plans	0.6		0.6				0.6
Issuance under employee stock plans, Shares		800,000
Stock-based compensation expense	12.8		12.8				12.8
Employees’ taxes paid upon vesting of restricted stock units	(1.5)		(1.5)				(1.5)
Employees' taxes paid upon vesting of restricted stock units, Shares		(100,000)
Net income (loss)	80.4				77.6		77.6	2.8
Other comprehensive income (loss)	6.4					6.4	6.4
Ending balance at Dec. 25, 2020	551.2
Beginning balance at Dec. 31, 2020	551.2	$ 0.1	312.8	$ (3.3)	217.9	5.1	532.6	18.6
Beginning balance, Shares at Dec. 31, 2020		40,600,000		600,000
Issuance under employee stock plans	0.8		0.8				0.8
Issuance under employee stock plans, Shares		700,000
Issuance of common stock	192.8		192.8				192.8
Issuance of common stock, Shares		3,700,000
Stock-based compensation expense	15.8		15.8				15.8
Employees’ taxes paid upon vesting of restricted stock units	(7.3)		(7.3)				(7.3)
Employees' taxes paid upon vesting of restricted stock units, Shares		(100,000)
Dividend income	0.1							0.1
Acquisition of Ham-Let	1.9							1.9
Reclassification related to Cinos Korea	16.5							16.5
Net income (loss)	126.4				119.5		119.5	6.9
Other comprehensive income (loss)	(5.3)					(5.3)	(5.3)
Ending balance at Dec. 31, 2021	892.7	$ 0.1	$ 514.9	$ (3.3)	$ 337.4	$ (0.2)	$ 848.9	43.8
Ending balance, Shares at Dec. 31, 2021		44,900,000		600,000
Dividend income	$ (0.1)							$ (0.1)