Benefit Plans - Expected Weighted Average Long-Term Rate of Return (Parenthetical) (Detail)	12 Months Ended
	Dec. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return on plan assets	5.00%	[1]
Primary Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return on plan assets	5.00%
Bargaining Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted average expected long-term rate of return on plan assets	5.25%

[1] The weighted average expected long-term rate of return of plan assets is 5.0% for the Primary Plan and 5.25% for the Bargaining Plan.