Fair Value (Schedule Of Assets And Liabilities Measured On A Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 29, 2013		Mar. 30, 2013		Jun. 30, 2012	Mar. 31, 2012
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	$ 40,489		$ 26,608
Liabilities, Fair Value Disclosure	9,685		9,673
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	111,696		110,715
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	1,900		13,800		13,600	25,900
Fair Value Inputs Level 1 Level 2 And Level 3, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	154,085		151,123
Liabilities, Fair Value Disclosure	9,685		9,673
Money Market Funds [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	25,729	[1]	13,476	[1]
Money Market Funds [Member] | Fair Value Inputs Level 1 Level 2 And Level 3, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	25,729		13,476
Municipal Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	82,398		58,658
Municipal Bonds [Member] | Fair Value Inputs Level 1 Level 2 And Level 3, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	82,398		58,658
Corporate Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	26,394		25,825
Corporate Bonds [Member] | Fair Value Inputs Level 1 Level 2 And Level 3, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	26,394		25,825
Government Agency Bonds [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure			16,187
Government Agency Bonds [Member] | Fair Value Inputs Level 1 Level 2 And Level 3, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure			16,187
Certificates Of Deposits [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	5,075		3,459
Certificates Of Deposits [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	1,406		4,300
Certificates Of Deposits [Member] | Fair Value Inputs Level 1 Level 2 And Level 3, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	6,481		7,759
Commercial Paper [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	1,498		5,745
Commercial Paper [Member] | Fair Value Inputs Level 1 Level 2 And Level 3, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	1,498		5,745
Equity Mutual Funds Related To NQDCP [Member] | Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	9,685		9,673
Equity Mutual Funds Related To NQDCP [Member] | Fair Value Inputs Level 1 Level 2 And Level 3, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	9,685		9,673
Long-Term Investments In ARS [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	1,900		13,800
Long-Term Investments In ARS [Member] | Fair Value Inputs Level 1 Level 2 And Level 3, Total [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, Fair Value Disclosure	$ 1,900		$ 13,800

[1] Money market funds of $25,729,000 and $13,476,000 were classified as cash equivalents as of June 29, 2013 and March 30, 2013, respectively.