Segment Information (Percentage Of Total Product Revenue Contributed By Company's Nutritional And Care Products) (Details)	3 Months Ended		9 Months Ended
	Oct. 03, 2015	Sep. 27, 2014	Oct. 03, 2015	Sep. 27, 2014
USANA Nutritionals [Member]
Revenue from External Customer [Line Items]
Percentage of product revenue	80.00%	78.00%	81.00%	79.00%
USANA Foods [Member]
Revenue from External Customer [Line Items]
Percentage of product revenue	12.00%	13.00%	12.00%	13.00%
Sense - Beautiful Science [Member]
Revenue from External Customer [Line Items]
Percentage of product revenue	7.00%	7.00%	6.00%	7.00%