Retirement and Other Employee Benefits - Net Periodic Pension Cost of Defined Benefit Pension and Post-Retirement Benefit Plans (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 27, 2019	Dec. 28, 2018	Dec. 29, 2017
Pension plans | United States
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0.0	$ 0.0	$ 0.0
Interest cost	0.6	0.5	0.6
Expected return on assets	(1.0)	(1.0)	(1.0)
Net amortization	0.4	0.4	0.4
Settlement loss	0.0	0.0	0.0
Net periodic cost (income)	0.0	(0.1)	0.0
Pension plans | United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Service cost	0.0	0.0	0.0
Interest cost	1.4	1.5	1.5
Expected return on assets	(2.0)	(2.5)	(2.4)
Net amortization	0.1	(0.4)	0.0
Settlement loss	0.4	0.0	0.0
Net periodic cost (income)	(0.1)	(1.4)	(0.9)
Post-retirement plans | Central America
Defined Benefit Plan Disclosure [Line Items]
Service cost	5.4	5.9	5.6
Interest cost	4.7	4.0	4.4
Expected return on assets	0.0	0.0	0.0
Net amortization	0.1	0.8	0.8
Settlement loss	0.0	0.0	0.0
Net periodic cost (income)	$ 10.2	$ 10.7	$ 10.8