Condensed Consolidated Statement of Changes in Shareholders' Equity Statement - USD ($) $ in Millions	Total	Ordinary Shares	Treasury Shares	Additional Paid-In Capital	Retained Earnings (Deficit)	Accumulated Other Comprehensive Loss
Shares, Outstanding		93,500,000	9,400,000
Beginning balance at Dec. 27, 2019	$ 1,940.7	$ 18.7	$ (1,615.7)	$ 5,562.5	$ (2,016.9)	$ (7.9)
Net loss	(50.2)				(50.2)
Other Comprehensive Income (Loss), Net of Tax	(1.3)					(1.3)
Vesting of restricted shares (in shares)		100,000	0
Vesting of restricted shares (in usd)	(0.1)	$ 0.0	$ 0.0	(0.1)
Share-based compensation	6.7			6.7
Ending balance at Mar. 27, 2020	$ 1,895.8	$ 18.7	$ (1,615.7)	5,569.1	(2,067.1)	(9.2)
Shares, Outstanding		93,600,000	9,400,000
Shares, Outstanding		94,100,000	9,500,000
Beginning balance, ordinary shares (in shares) at Dec. 25, 2020	94,111,303
Beginning balance, treasury shares (in shares) at Dec. 25, 2020	9,506,147
Beginning balance at Dec. 25, 2020	$ 1,019.2	$ 18.8	$ (1,616.1)	5,587.6	(2,961.5)	(9.6)
Net loss	(143.9)				(143.9)
Other Comprehensive Income (Loss), Net of Tax	0.1					0.1
Vesting of restricted shares (in shares)		0	0
Vesting of restricted shares (in usd)	(0.1)	$ 0.0	$ 0.0	(0.1)
Share-based compensation	$ 3.6			3.6
Ending balance, ordinary shares (in shares) at Mar. 26, 2021	94,145,367
Ending balance, treasury shares (in shares) at Mar. 26, 2021	9,518,213
Ending balance at Mar. 26, 2021	$ 878.9	$ 18.8	$ (1,616.1)	$ 5,591.1	$ (3,105.4)	$ (9.5)
Shares, Outstanding		94,100,000	9,500,000