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		92,700,000	9,400,000
Beginning balance at Dec. 28, 2018	$ 2,887.3	$ 18.5	$ (1,617.4)	$ 5,528.2	$ (1,017.7)	$ (24.3)
Net (loss) income	154.9				154.9
Other Comprehensive Income (Loss), Net of Tax	1.3					1.3
Stock Issued During Period, Value, Stock Options Exercised	0.3			0.3
Vesting of restricted shares (in shares)		200,000	0
Vesting of restricted shares (in usd)	(0.4)	$ 0.1	$ (0.5)	0.0
Share-based compensation	$ 10.0			10.0
Reissuance of treasury shares (in shares)	0
Reissuance of treasury shares	$ (0.5)		(0.9)		(0.4)
Ending balance at Mar. 29, 2019	3,053.9	$ 18.6	$ (1,617.0)	5,538.5	(863.7)	(22.5)
Cumulative Effect of New Accounting Principle in Period of Adoption | Accounting Standards Update 2018-02 [Member]	$ 0.0				(0.5)	0.5
Shares, Outstanding		92,900,000	9,400,000
Shares, Outstanding		93,500,000	9,400,000
Beginning balance, ordinary shares (in shares) at Dec. 27, 2019	93,459,206
Beginning balance, treasury shares (in shares) at Dec. 27, 2019	9,353,420
Beginning balance at Dec. 27, 2019	$ 1,940.7	$ 18.7	$ (1,615.7)	5,562.5	(2,016.9)	(7.9)
Net (loss) income	(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, ordinary shares (in shares) at Mar. 27, 2020	93,576,710
Ending balance, treasury shares (in shares) at Mar. 27, 2020	9,368,269
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