Quarterly report pursuant to Section 13 or 15(d)

Line Of Credit (Details)

v2.4.1.9
Line Of Credit (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Apr. 04, 2015
Jan. 03, 2015
Line of Credit Facility [Line Items]    
Maturity date Feb. 01, 2024  
Line of Credit [Member]    
Line of Credit Facility [Line Items]    
Credit facility $ 75,000us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
/ us-gaap_CreditFacilityAxis
= us-gaap_LineOfCreditMember
 
Reduction in available borrowing limit 4,366usna_LineOfCreditFacilityIncreaseDecreaseInBorrowingCapacity
/ us-gaap_CreditFacilityAxis
= us-gaap_LineOfCreditMember
4,575usna_LineOfCreditFacilityIncreaseDecreaseInBorrowingCapacity
/ us-gaap_CreditFacilityAxis
= us-gaap_LineOfCreditMember
Outstanding debt $ 0us-gaap_LineOfCredit
/ us-gaap_CreditFacilityAxis
= us-gaap_LineOfCreditMember
$ 0us-gaap_LineOfCredit
/ us-gaap_CreditFacilityAxis
= us-gaap_LineOfCreditMember
Maturity date Apr. 01, 2016