Postretirement Plans - Summary of Amounts Included in Accumulated Other Comprehensive Income on Accompanying Consolidated Balance Sheets (Detail) - U.S. Postretirement Health Care Plans - USD ($) $ in Millions	Jan. 02, 2021	Dec. 28, 2019
Defined Benefit Plan Disclosure [Line Items]
Net gain, net of tax of $0.5 million and $1.1 million, respectively	$ 1.3	$ 3.2
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent
Defined Benefit Plan Disclosure [Line Items]
AOCI, tax	$ 0.5	$ 1.1