Marketable Securities - Schedule of Amortized Cost and Estimated Fair Value of Debt Securities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 29, 2013	Mar. 31, 2013
Available For Sale Securities Debt Maturities Fair Value [Abstract]
Due in one year or less, Amortized Cost	$ 113,774
Due after one year through three years, Amortized Cost	169,051
Due after three years through five years, Amortized Cost	35,240
Due after five years, Amortized Cost	35,022
Total amortized cost of debt securities	353,087	357,608
Due in one year or less, Estimated Fair Value	113,863
Due after one year through three years, Estimated Fair Value	169,259
Due after three years through five years, Estimated Fair Value	34,906
Due after five years, Estimated Fair Value	35,405
Available-for-sale securities, Estimated Fair Value	$ 353,433	$ 359,974