Retirement and Other Employee Benefits - Fair Values of Plan Assets by Asset Category (Detail) - USD ($) $ in Millions	Dec. 27, 2024	Dec. 29, 2023	Dec. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		$ 11.4
Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		5.2
Value securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		2.3
Growth securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		3.9
Quoted Prices in Active Markets for Identical Assets (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		11.4
Quoted Prices in Active Markets for Identical Assets (Level 1) | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		5.2
Quoted Prices in Active Markets for Identical Assets (Level 1) | Value securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		2.3
Quoted Prices in Active Markets for Identical Assets (Level 1) | Growth securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets		3.9
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	$ 11.3	11.4	$ 11.1
United States | Pension plans | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	4.5
United States | Pension plans | Value securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	2.4
United States | Pension plans | Growth securities
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	4.4
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	11.3
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	4.5
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	2.4
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	4.4
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	39.1	42.2	$ 37.9
United Kingdom | Pension plans | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.8	0.5
United Kingdom | Pension plans | Real estate investment trusts
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.1	1.7
United Kingdom | Pension plans | Diversified growth funds
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	3.3	7.1
United Kingdom | Pension plans | Other international companies
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.8	0.7
United Kingdom | Pension plans | Government and corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	31.7	20.3
United Kingdom | Pension plans | Liability-driven investments
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	2.4	11.9
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	0.5
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	0.5
United Kingdom | Pension plans | Quoted Prices in Active Markets for Identical Assets (Level 1) | Real estate investment trusts
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) | Government and corporate 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	38.3	41.7
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) | Real estate investment trusts
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.1	1.7
United Kingdom | Pension plans | Significant Observable Inputs (Level 2) | Diversified growth funds
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	3.3	7.1
United Kingdom | Pension plans | Significant Observable Inputs (Level 2) | Other international companies
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	0.8	0.7
United Kingdom | Pension plans | Significant Observable Inputs (Level 2) | Government and corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	31.7	20.3
United Kingdom | Pension plans | Significant Observable Inputs (Level 2) | Liability-driven investments
Defined Benefit Plan Disclosure [Line Items]
Fair values of plan assets	2.4	11.9
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) | Real estate investment trusts
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) | Government and corporate 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