Retirement and Other Employee Benefits - Fair Values of Plan Assets by Asset Category (Detail) - USD ($) $ in Millions	Dec. 28, 2018	Dec. 29, 2017	Dec. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		$ 13.9
Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		5.7
Value securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		3.8
Growth securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		4.4
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		13.9
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		5.7
Quoted Prices in Active Markets for Identical Assets (Level 1) | Value securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		3.8
Quoted Prices in Active Markets for Identical Assets (Level 1) | Growth securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		4.4
Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		0.0
Significant Observable Inputs (Level 2) | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		0.0
Significant Observable Inputs (Level 2) | Value securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		0.0
Significant Observable Inputs (Level 2) | Growth securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		0.0
Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		0.0
Significant Unobservable Inputs (Level 3) | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		0.0
Significant Unobservable Inputs (Level 3) | Value securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		0.0
Significant Unobservable Inputs (Level 3) | Growth securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		0.0
United States | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	$ 11.9	13.9	$ 13.1
United States | Pension plans | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	5.4
United States | Pension plans | Value securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	2.2
United States | Pension plans | Growth securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	4.3
United States | Pension plans | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	11.9
United States | Pension plans | Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	5.4
United States | Pension plans | Quoted Prices in Active Markets for Identical Assets (Level 1) | Value securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	2.2
United States | Pension plans | Quoted Prices in Active Markets for Identical Assets (Level 1) | Growth securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	4.3
United States | Pension plans | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0
United States | Pension plans | Significant Observable Inputs (Level 2) | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0
United States | Pension plans | Significant Observable Inputs (Level 2) | Value securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0
United States | Pension plans | Significant Observable Inputs (Level 2) | Growth securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0
United States | Pension plans | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0
United States | Pension plans | Significant Unobservable Inputs (Level 3) | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0
United States | Pension plans | Significant Unobservable Inputs (Level 3) | Value securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0
United States | Pension plans | Significant Unobservable Inputs (Level 3) | Growth securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0
United Kingdom | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	52.3	61.3	$ 50.5
United Kingdom | Pension plans | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.8	0.2
United Kingdom | Pension plans | United Kingdom companies
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	4.5	5.5
United Kingdom | Pension plans | Diversified growth funds
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	17.5	20.8
United Kingdom | Pension plans | Other international companies
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	15.0	18.5
United Kingdom | Pension plans | United Kingdom government bonds
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	6.1	7.1
United Kingdom | Pension plans | Liability-driven investments
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	8.4	9.2
United Kingdom | Pension plans | Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.8	0.2
United Kingdom | Pension plans | Quoted Prices in Active Markets for Identical Assets (Level 1) | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.8	0.2
United Kingdom | Pension plans | Quoted Prices in Active Markets for Identical Assets (Level 1) | United Kingdom companies
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0	0.0
United Kingdom | Pension plans | Quoted Prices in Active Markets for Identical Assets (Level 1) | Diversified growth funds
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0	0.0
United Kingdom | Pension plans | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other international companies
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0	0.0
United Kingdom | Pension plans | Quoted Prices in Active Markets for Identical Assets (Level 1) | United Kingdom government bonds
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0	0.0
United Kingdom | Pension plans | Quoted Prices in Active Markets for Identical Assets (Level 1) | Liability-driven investments
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0	0.0
United Kingdom | Pension plans | Significant Observable Inputs (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	51.5	61.1
United Kingdom | Pension plans | Significant Observable Inputs (Level 2) | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0	0.0
United Kingdom | Pension plans | Significant Observable Inputs (Level 2) | United Kingdom companies
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	4.5	5.5
United Kingdom | Pension plans | Significant Observable Inputs (Level 2) | Diversified growth funds
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	17.5	20.8
United Kingdom | Pension plans | Significant Observable Inputs (Level 2) | Other international companies
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	15.0	18.5
United Kingdom | Pension plans | Significant Observable Inputs (Level 2) | United Kingdom government bonds
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	6.1	7.1
United Kingdom | Pension plans | Significant Observable Inputs (Level 2) | Liability-driven investments
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	8.4	9.2
United Kingdom | Pension plans | Significant Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0	0.0
United Kingdom | Pension plans | Significant Unobservable Inputs (Level 3) | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0	0.0
United Kingdom | Pension plans | Significant Unobservable Inputs (Level 3) | United Kingdom companies
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0	0.0
United Kingdom | Pension plans | Significant Unobservable Inputs (Level 3) | Diversified growth funds
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0	0.0
United Kingdom | Pension plans | Significant Unobservable Inputs (Level 3) | Other international companies
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0	0.0
United Kingdom | Pension plans | Significant Unobservable Inputs (Level 3) | United Kingdom government bonds
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.0	0.0
United Kingdom | Pension plans | Significant Unobservable Inputs (Level 3) | Liability-driven investments
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	$ 0.0	$ 0.0