USANA Health Sciences, Inc. Quarterly report pursuant to Section 13 or 15(d)

Segment Information (Schedule Of Revenues From External Customers And Assets By Geographic Region) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Apr. 04, 2015	Mar. 29, 2014
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Sales to External Customers	$ 219,378us-gaap_SalesRevenueGoodsNet	$ 182,401us-gaap_SalesRevenueGoodsNet
Americas And Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Sales to External Customers	63,524	63,815
Southeast Asia/Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Sales to External Customers	45,339	40,448
Greater China [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Sales to External Customers	101,286	70,847
North Asia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Sales to External Customers	9,229	7,291
Asia Pacific [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Sales to External Customers	$ 155,854	$ 118,586