FAIR VALUE MEASURES - Narrative (Details) - USD ($)	Apr. 04, 2026	Jan. 03, 2026
Fair Value Disclosures [Abstract]
Nonfinancial assets, fair value disclosure	$ 0	$ 0

The amount of nonfinancial assets measured at fair value.

No definition available.

Name:	usna_NonfinancialAssetsFairValueDisclosure
Namespace Prefix:	usna_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant