Marketable Securities (Schedule of Cost And Estimated Fair Value Of Available-for-sale Securities By Contractual Maturity) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 28, 2013	Mar. 30, 2013
Marketable Securities [Abstract]
Within 1 year, Amortized Cost	$ 199,375	$ 105,290
After 1 year, Amortized Cost	40,236	65,004
Within 1 year, Estimated Fair Value	199,423	105,235
After 1 year, Estimated Fair Value	40,254	64,910
Amortized Cost	239,611	170,294
Estimated Fair Value	$ 239,677	$ 170,145