Marketable Securities - SERP Investments (Details) - USD ($) $ in Thousands	3 Months Ended
Apr. 01, 2023	Mar. 26, 2022
Net Investment Income [Line Items]
Investment Income (Loss) and Interest Expense	$ 3,798	$ (881)
Supplemental Employee Retirement Plan [Member]
Net Investment Income [Line Items]
Investment Income (Loss) and Interest Expense	$ 1,300	$ 1,500

Amount after accretion (amortization) of discount (premium), and investment expense, of interest income and dividend income on nonoperating securities plus amount of the cost of borrowed funds accounted for as interest expense.

No definition available.

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Namespace Prefix:	wmk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration