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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. 31, 2016
Jan. 02, 2016
Jan. 03, 2015
SpartanNash Company Pension Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Interest cost $ 2,977 $ 3,325 $ 4,223
Expected return on plan assets (4,269) (4,923) (5,737)
Recognized actuarial net loss 706 827 970
Net periodic benefit (income) expense (586) (771) (544)
Settlement expense 692   2,588
Total expense (income) $ 106 $ (771) $ 2,044
Weighted average assumptions at measurement date:      
Discount rate 4.04% 3.75%  
Expected return on plan assets 5.05% 5.50%  
SpartanNash Company Pension Plan [Member] | Minimum [Member]      
Weighted average assumptions at measurement date:      
Discount rate     4.35%
Expected return on plan assets     5.95%
SpartanNash Company Pension Plan [Member] | Maximum [Member]      
Weighted average assumptions at measurement date:      
Discount rate     4.65%
Expected return on plan assets     5.70%
SpartanNash Medical Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Service cost $ 187 $ 231 $ 186
Interest cost 345 404 394
Amortization of prior service cost (158) (158) (158)
Recognized actuarial net loss 42 174 20
Net periodic benefit (income) expense 416 651 442
Total expense (income) $ 416 $ 651 $ 442
Weighted average assumptions at measurement date:      
Discount rate 4.55% 4.15% 5.05%