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v3.20.1

Note B - Summary of Significant Accounting Policies - Property and Equipment (Details) | 12 Months Ended
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Mar. 29, 2020
Building and Building Improvements [Member] | Minimum [Member] |
Building and improvements (years) (Year) | 5 years
Building and Building Improvements [Member] | Maximum [Member] |
Building and improvements (years) (Year) | 25 years
Machinery, Equipment, Furniture, and Fixtures [Member] | Minimum [Member] |
Building and improvements (years) (Year) | 3 years
Machinery, Equipment, Furniture, and Fixtures [Member] | Maximum [Member] |
Building and improvements (years) (Year) | 15 years
Leasehold Improvements [Member] | Minimum [Member] |
Building and improvements (years) (Year) | 5 years
Leasehold Improvements [Member] | Maximum [Member] |
Building and improvements (years) (Year) | 20 years

X
- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_BuildingAndBuildingImprovementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=nath_MachineryEquipmentFurnitureAndFixturesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_LeaseholdImprovementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |