Lease Commitments (Narrative) (Details)	12 Months Ended
Dec. 29, 2018
Operating Leased Assets [Line Items]
Percentage of facilities under operating lease	53.00%
Lease Expiration Date	Dec. 31, 2033
Maximum [Member]
Operating Leased Assets [Line Items]
Lessee, Operating Lease, Renewal Term	20 years
Minimum [Member]
Operating Leased Assets [Line Items]
Lessee, Operating Lease, Renewal Term	5 years

Date which lease or group of leases is set to expire, in CCYY-MM-DD format.

No definition available.

Name:	us-gaap_LeaseExpirationDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=77888426&loc=SL77918673-209980

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of open store facilities leased through operating leasing arrangements.

+ References

No definition available.

+ Details

Name:	wmk_PercentageOfFacilitiesUnderOperatingLease
Namespace Prefix:	wmk_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
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Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
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Balance Type:
Period Type: