Note 4 - Fair Value (Details) - Summary of the Gross Unrealized Losses and Fair Values of Investments (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Dec. 29, 2013	Mar. 31, 2013
Note 4 - Fair Value (Details) - Summary of the Gross Unrealized Losses and Fair Values of Investments [Line Items]
Fair Value Less than 12 Months	$ 89,017	$ 42,528
Gross Unrealized Losses Less than 12 Months	(166)	(98)
Fair Value Greater than 12 Months	5,641	5,405
Gross Unrealized Losses Greater than 12 Months	(58)	(80)
Fair Value Total	94,658	47,933
Gross Unrealized Losses Total	(224)	(178)
US Government Corporation And Agencies [Member]
Note 4 - Fair Value (Details) - Summary of the Gross Unrealized Losses and Fair Values of Investments [Line Items]
Fair Value Less than 12 Months	28,772
Gross Unrealized Losses Less than 12 Months	(50)
Fair Value Total	28,772
Gross Unrealized Losses Total	(50)
US States and Political Subdivisions Debt Securities [Member]
Note 4 - Fair Value (Details) - Summary of the Gross Unrealized Losses and Fair Values of Investments [Line Items]
Fair Value Less than 12 Months	1,516
Gross Unrealized Losses Less than 12 Months	(4)
Fair Value Greater than 12 Months		404
Gross Unrealized Losses Greater than 12 Months		(2)
Fair Value Total	1,516	404
Gross Unrealized Losses Total	(4)	(2)
Corporate Debt Securities [Member]
Note 4 - Fair Value (Details) - Summary of the Gross Unrealized Losses and Fair Values of Investments [Line Items]
Fair Value Less than 12 Months	35,179	29,609
Gross Unrealized Losses Less than 12 Months	(65)	(42)
Fair Value Greater than 12 Months		497
Gross Unrealized Losses Greater than 12 Months		(3)
Fair Value Total	35,179	30,106
Gross Unrealized Losses Total	(65)	(45)
Asset-backed Securities [Member]
Note 4 - Fair Value (Details) - Summary of the Gross Unrealized Losses and Fair Values of Investments [Line Items]
Fair Value Less than 12 Months	15,301	10,008
Gross Unrealized Losses Less than 12 Months	(25)	(17)
Fair Value Greater than 12 Months	3,467	1,241
Gross Unrealized Losses Greater than 12 Months	(31)	(10)
Fair Value Total	18,768	11,249
Gross Unrealized Losses Total	(56)	(27)
Collateralized Mortgage Backed Securities [Member]
Note 4 - Fair Value (Details) - Summary of the Gross Unrealized Losses and Fair Values of Investments [Line Items]
Fair Value Less than 12 Months	8,249	2,911
Gross Unrealized Losses Less than 12 Months	(22)	(39)
Fair Value Greater than 12 Months	2,174	3,263
Gross Unrealized Losses Greater than 12 Months	(27)	(65)
Fair Value Total	10,423	6,174
Gross Unrealized Losses Total	$ (49)	$ (104)