XML 56 R44.htm IDEA: XBRL DOCUMENT v3.10.0.1
Associate Retirement Plans - Additional Information (Detail) - USD ($)
 3 Months Ended 9 Months Ended
Feb. 28, 2018
Oct. 06, 2018
Oct. 07, 2017
Oct. 06, 2018
Oct. 07, 2017
Defined Benefit Plan Disclosure [Line Items]          
Pension contributions during last plan year   $ 2,100,000 $ 2,400,000 $ 10,000,000 $ 10,200,000
Pension Plan or Plan [Member]          
Defined Benefit Plan Disclosure [Line Items]          
Frozen pension plan, termination date       Jul. 31, 2018  
Pension Plan or Plan [Member] | Minimum [Member]          
Defined Benefit Plan Disclosure [Line Items]          
Distribution of assets to plan participants, expected period       6 months  
One-time, pre-tax settlement charge $ 20,000,000        
Pension Plan or Plan [Member] | Maximum [Member]          
Defined Benefit Plan Disclosure [Line Items]          
Distribution of assets to plan participants, expected period       18 months  
One-time, pre-tax settlement charge $ 21,000,000        
Retiree Medical Plan [Member]          
Defined Benefit Plan Disclosure [Line Items]          
Expected Company contribution for remainder of fiscal year   400,000   $ 400,000  
SpartanNash Company Pension Plan [Member] | Pension Plan or Plan [Member]          
Defined Benefit Plan Disclosure [Line Items]          
Net periodic benefit (income) expense   (100,000) (100,000) (300,000) (500,000)
Standard pension funding carryover   1,500,000   1,500,000  
Expected Company contribution for remainder of fiscal year   0   0  
SpartanNash Retiree Medical Plan [Member] | Retiree Medical Plan [Member]          
Defined Benefit Plan Disclosure [Line Items]          
Net periodic benefit (income) expense   $ 100,000 $ 100,000 $ 400,000 $ 300,000