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Segment Information (Schedule Of Revenue Percentage By Product) (Details) | 12 Months Ended
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Dec. 31, 2016 | Jan. 02, 2016 | Jan. 03, 2015
USANA Nutritionals [Member] |  |  |
Revenue from External Customer [Line Items] |  |  |
Percentage of product revenue | 83.00% | 81.00% | 79.00%
USANA Foods [Member] |  |  |
Revenue from External Customer [Line Items] |  |  |
Percentage of product revenue | 10.00% | 11.00% | 13.00%
Sense - Beautiful Science [Member] |  |  |
Revenue from External Customer [Line Items] |  |  |
Percentage of product revenue | 6.00% | 7.00% | 7.00%

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- 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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- Definition Percentage Of Product Revenue + References No definition available. + Details
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Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

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- Details
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Namespace Prefix: |
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Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
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Balance Type: |
Period Type: |

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- Details
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Namespace Prefix: |
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Balance Type: |
Period Type: |