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Associate Retirement Plans - Additional Information (Detail) - USD ($)
 3 Months Ended 9 Months Ended
Feb. 28, 2018
Oct. 05, 2019
Oct. 06, 2018
Oct. 05, 2019
Oct. 06, 2018
Defined Benefit Plan Disclosure [Line Items]          
Pension contributions during last plan year   $ 2,400,000 $ 2,100,000 $ 10,600,000 $ 10,000,000.0
Pension Plan [Member]          
Defined Benefit Plan Disclosure [Line Items]          
Pre-tax settlement charges $ 18,200,000        
Frozen pension plan, termination date       Jul. 31, 2018  
Settlement and other termination expenses, recognized   9,400,000   $ 1,300,000  
Standard pension funding carryover       0  
Retiree Medical Plan [Member]          
Defined Benefit Plan Disclosure [Line Items]          
Standard pension funding carryover       300,000  
Expected Company contribution for remainder of fiscal year   400,000   400,000  
SpartanNash Company Pension Plan [Member] | Pension Plan [Member]          
Defined Benefit Plan Disclosure [Line Items]          
Net periodic benefit (income) expense   10,100,000 (100,000) 19,300,000 (300,000)
SpartanNash Retiree Medical Plan [Member] | Retiree Medical Plan [Member]          
Defined Benefit Plan Disclosure [Line Items]          
Net periodic benefit (income) expense   $ 100,000 $ 100,000 $ 300,000 $ 400,000