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Associate Retirement Plans - Components of Net Periodic Pension and Postretirement Benefit Cost (Income) (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 30, 2017
Dec. 31, 2016
Jan. 02, 2016
Pension Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Interest cost $ 2,345 $ 2,977 $ 3,325
Expected return on plan assets (3,836) (4,269) (4,923)
Recognized actuarial net loss 221 706 827
Net periodic benefit (income) expense (1,270) (586) (771)
Settlement expense 548 692  
Total (income) expense $ (722) $ 106 $ (771)
Weighted average assumptions at measurement date:      
Discount rate 3.82% 4.04% 3.75%
Expected return on plan assets 4.83% 5.05% 5.50%
Retiree Medical Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Service cost $ 184 $ 187 $ 231
Interest cost 345 345 404
Amortization of prior service cost (158) (158) (158)
Recognized actuarial net loss 59 42 174
Net periodic benefit (income) expense 430 416 651
Total (income) expense $ 430 $ 416 $ 651
Weighted average assumptions at measurement date:      
Discount rate 4.26% 4.55% 4.15%