Benefits Expected to be Paid from Plans Assets (Parenthetical) (Detail) - Includes Plan No 1 and No 2 Single Lump Sum - USD ($) $ in Millions	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016
Lump Sums Plan No. 1
Schedule of Pension and Other Postretirement Benefits Expected Benefit Payments [Line Items]
Distributions from existing plan assets		$ 15.7
Lump Sums Plan No. 2
Schedule of Pension and Other Postretirement Benefits Expected Benefit Payments [Line Items]
Distributions from existing plan assets		$ 1.6
Lump Sums Plan No. 1
Schedule of Pension and Other Postretirement Benefits Expected Benefit Payments [Line Items]
Distributions from existing plan assets	$ 14.4
Lump Sums Plan No. 2
Schedule of Pension and Other Postretirement Benefits Expected Benefit Payments [Line Items]
Distributions from existing plan assets	$ 1.6