Note 2 - Marketable Securities - Summary of Realized Gains (Losses) on Available-for-Sale Securities (Details) - USD ($) $ in Thousands	12 Months Ended
Feb. 27, 2022	Feb. 28, 2021	Mar. 01, 2020
Gross realized gains on sale	$ 26	$ 155	$ 90
Gross realized losses on sale	$ 36	$ 145	$ 75

Amount of realized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27357-111563

Name:	us-gaap_DebtSecuritiesAvailableForSaleRealizedGain
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration