Marketable Securities - SERP Investments (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 25, 2021	Dec. 26, 2020	Dec. 28, 2019
Net Investment Income [Line Items]
Investment Income (Loss) and Interest Expense	$ 5,007	$ 3,817	$ 7,054
Supplemental Employee Retirement Plan [Member]
Net Investment Income [Line Items]
Investment Income (Loss) and Interest Expense	$ 3,400	$ 3,300	$ 3,000

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