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Associate Retirement Plans - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		4 Months Ended	9 Months Ended
	Oct. 09, 2021	Oct. 03, 2020	Apr. 18, 2020	Oct. 09, 2021	Oct. 03, 2020
Defined Benefit Plan Disclosure [Line Items]
Pension contributions during last plan year	$ 2.2	$ 2.5		$ 10.3	$ 10.6
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit (income) expense			$ 1.0
Retiree Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected Company contribution for remainder of fiscal year	0.5			0.5
Standard pension funding carryover				0.3
SpartanNash Retiree Medical Plan Plan [Member] \| Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit (income) expense	$ 0.2	$ 0.1		$ 0.5	$ 0.5