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Note A - Basis of Presentation (Details Textual) | Dec. 27, 2020
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COVID 19 [Member] |
Percentage of Franchises Open | 60.00%

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- Definition The percentage of franchises open. + References No definition available. + Details
Name: | nath_PercentageOfFranchisesOpen
Namespace Prefix: | nath_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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- Details
Name: | us-gaap_UnusualOrInfrequentItemAxis=nath_Covid19Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |