Financial Instruments (Details 1) (USD $) In Thousands, unless otherwise specified	Dec. 27, 2014	Mar. 29, 2014
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	$ 794,418	$ 751,113
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(5,513)	(13,394)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	250,823	158,767
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(8,940)	(4,759)
Available-for-Sale Securities, Fair Value, Total	1,045,241	909,880
Available-for-Sale Securities, Gross Unrealized Losses, Total	(14,453)	(18,153)
Non-financial institution securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	4,385	112,470
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(4)	(1,167)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	0	4,488
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	0	(77)
Available-for-Sale Securities, Fair Value, Total	4,385	116,958
Available-for-Sale Securities, Gross Unrealized Losses, Total	(4)	(1,244)
Auction Rate Securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	0	0
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	0	0
Available-for-Sale Securities, 12 Months or Greater, Fair Value	10,325	20,160
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(175)	(1,340)
Available-for-Sale Securities, Fair Value, Total	10,325	20,160
Available-for-Sale Securities, Gross Unrealized Losses, Total	(175)	(1,340)
Municipal Bonds [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	8,814	5,917
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(113)	(166)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	2,968	1,743
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(80)	(39)
Available-for-Sale Securities, Fair Value, Total	11,782	7,660
Available-for-Sale Securities, Gross Unrealized Losses, Total	(193)	(205)
U.S. Government and Agency Securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	137,031	118,125
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(134)	(184)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	0	0
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	0	0
Available-for-Sale Securities, Fair Value, Total	137,031	118,125
Available-for-Sale Securities, Gross Unrealized Losses, Total	(134)	(184)
Mortgage-Backed Securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	362,105	457,903
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(2,808)	(7,225)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	181,355	132,376
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(3,510)	(3,303)
Available-for-Sale Securities, Fair Value, Total	543,460	590,279
Available-for-Sale Securities, Gross Unrealized Losses, Total	(6,318)	(10,528)
Asset-backed Securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	157,697
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(475)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	0
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	0
Available-for-Sale Securities, Fair Value, Total	157,697
Available-for-Sale Securities, Gross Unrealized Losses, Total	(475)
Debt Mutual Fund [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	39,500	56,698
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(500)	(4,652)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	56,175	0
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	(5,175)	0
Available-for-Sale Securities, Fair Value, Total	95,675	56,698
Available-for-Sale Securities, Gross Unrealized Losses, Total	(5,675)	(4,652)
Bank Loans [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	84,886
Available-for-Sale Securities, Less Than 12 Months, Gross Unrealized Losses	(1,479)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	0
Available-for-Sale Securities, 12 Months or Greater, Gross Unrealized Losses	0
Available-for-Sale Securities, Fair Value, Total	84,886
Available-for-Sale Securities, Gross Unrealized Losses, Total	$ (1,479)

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

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+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-Topic 320

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-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

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