Marketable Securities (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Mar. 26, 2011
Schedule of Available-for-sale Securities [Line Items]
Minimum maturity period of investments to be classified as available-for-sale securities	90 days
Gross unrealized losses	$ 39	$ 47
Amortized costs	118,783	172,214
28 Different Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized losses		47
Amortized costs		61,800
Number of securities		28
37 Different Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized losses	39
Amortized costs	$ 72,600
Number of securities	37