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Associate Retirement Plans - Additional Information (Detail) - USD ($) $ in Millions |  |  | 3 Months Ended | 4 Months Ended | 6 Months Ended
--- | --- | --- | --- | --- | ---
Jul. 01, 2023 | Jul. 01, 2022 | Jul. 15, 2023 | Jul. 16, 2022 | Apr. 22, 2023 | Jul. 15, 2023 | Jul. 16, 2022
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |
Gain realized related to refund |  |  |  |  | $ 0.2 |  |
Pension contributions during last plan year |  |  | $ 3.3 | $ 3.1 |  | $ 7.6 | $ 6.9
Retiree Medical Plan [Member] |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |
Net periodic benefit (income) expense |  |  | 0.8 |  |  | 1.8 |
Increase (Decrease) in obligations |  |  |  |  |  | 6.6 |
SpartanNash Retiree Medical Plan Plan [Member] |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |
Net periodic benefit (income) expense | $ 0.3 | $ 0.7 |  |  |  |  |
Payment to retired participants | $ 1.3 | $ 2.0 |  |  |  |  |
SpartanNash Retiree Medical Plan Plan [Member] | Pension Plan [Member] |  |  |  |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |  |  |  |
Net periodic benefit (income) expense |  |  | $ 0.6 | $ 0.7 |  | $ 1.5 | $ 0.9

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