Retirement Plans - Asset Allocations (Detail) - USD ($) $ in Millions		Dec. 28, 2024		Dec. 30, 2023	Dec. 31, 2022
Schedule Of Other Postretirement Benefits [Line Items]
Fair value of plan assets		$ 227.9		$ 262.7	$ 251.4
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage		100.00%		100.00%
Equity securities [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage		46.00%		46.70%
Equity securities [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Fair value of plan assets	[1]	$ 104.8		$ 122.7
Fixed income securities [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage		34.90%		32.70%
Fixed income securities [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Fair value of plan assets	[1]	$ 79.6		$ 85.8
Cash and Cash Equivalents
Schedule Of Other Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage		18.40%		19.90%
Cash and Cash Equivalents | Fair Value Measured at Net Asset Value Per Share [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Fair value of plan assets		$ 41.9		$ 52.4
Other Investments [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage		0.70%		0.70%
Other Investments [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Fair value of plan assets		$ 1.6	[2]	$ 1.8

[1] In accordance with ASC 820, Fair Value Measurement (“ASC 820”), certain investments are measured at fair value using the net asset value per share as a practical expedient. These assets have not been classified in the fair value hierarchy.

[2] In accordance with ASC 820, investments have been measured using valuation techniques in which one or more significant inputs are unobservable (Level 3). See Note 1 for additional information.