Marketable Securities (Summary Of Available-For-Sale Securities) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 03, 2013	Feb. 26, 2012
Schedule of Available-for-sale Securities [Line Items]
Unamortized cost basis	$ 89,152	$ 139,245
Gross Unrealized Gains	58	102
Gross Unrealized Losses	111	65
U.S. Treasury And Other Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Unamortized cost basis	48,293	93,491
Gross Unrealized Gains	47	41
Gross Unrealized Losses	48	53
U.S. Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Unamortized cost basis	40,859	45,754
Gross Unrealized Gains	11	61
Gross Unrealized Losses	$ 63	$ 12