Retirement Plans - Asset Allocations (Detail) - USD ($) $ in Millions		Jan. 01, 2022	Jan. 02, 2021	Dec. 28, 2019
Schedule Of Other Postretirement Benefits [Line Items]
Fair value of plan assets		$ 323.0	$ 305.0	$ 287.6
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		56.10%	56.80%
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]	$ 181.3	$ 173.3
Fixed income securities [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage		36.80%	37.00%
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]	$ 118.9	$ 112.7
Real Estate Investment [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage		6.20%	5.50%
Real Estate Investment [Member] | Fair Value Measured at Net Asset Value Per Share [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Fair value of plan assets	[1]	$ 19.9	$ 16.7
Other Investments [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Defined Benefit Plan, Plan Assets, Actual Allocation, Percentage		0.90%	0.70%
Other Investments [Member] | Fair Value, Inputs, Level 3 [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Fair value of plan assets	[2]	$ 2.9	$ 2.3

[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.