Financial Instruments (Details 1) - USD ($) $ in Thousands	Apr. 01, 2017	Apr. 02, 2016
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	$ 1,310,037	$ 750,635
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(15,101)	(5,672)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	258,680	285,805
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(17,571)	(12,630)
Available-for-Sale Securities, Fair Value, Total	1,568,717	1,036,440
Available-for-Sale Securities, Gross Unrealized Losses, Total	(32,672)	(18,302)
Non-financial institution securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	68,850	52,756
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(492)	(230)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	1,022	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(4)	0
Available-for-Sale Securities, Fair Value, Total	69,872	52,756
Available-for-Sale Securities, Gross Unrealized Losses, Total	(496)	(230)
Auction Rate Securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		0
Available-for-Sale Securities, 12 Months or Greater, Fair Value		9,977
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(523)
Available-for-Sale Securities, Fair Value, Total		9,977
Available-for-Sale Securities, Gross Unrealized Losses, Total		(523)
Municipal Bonds [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value		10,138
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		(44)
Available-for-Sale Securities, 12 Months or Greater, Fair Value		3,867
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(89)
Available-for-Sale Securities, Fair Value, Total		14,005
Available-for-Sale Securities, Gross Unrealized Losses, Total		(133)
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	64,895	84,024
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(223)	(71)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	0	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Available-for-Sale Securities, Fair Value, Total	64,895	84,024
Available-for-Sale Securities, Gross Unrealized Losses, Total	(223)	(71)
Mortgage-Backed Securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	811,058	346,560
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(11,872)	(3,916)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	139,931	114,285
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(2,885)	(1,464)
Available-for-Sale Securities, Fair Value, Total	950,989	460,845
Available-for-Sale Securities, Gross Unrealized Losses, Total	(14,757)	(5,380)
Asset-backed Securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	119,845	81,038
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(651)	(502)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	4,689	20,793
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(35)	(103)
Available-for-Sale Securities, Fair Value, Total	124,534	101,831
Available-for-Sale Securities, Gross Unrealized Losses, Total	(686)	(605)
Debt Mutual Fund [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, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	0
Available-for-Sale Securities, 12 Months or Greater, Fair Value	88,676	91,901
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(12,674)	(9,449)
Available-for-Sale Securities, Fair Value, Total	88,676	91,901
Available-for-Sale Securities, Gross Unrealized Losses, Total	(12,674)	(9,449)
Bank Loans [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	15,139	34,358
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(106)	(31)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	0	42,832
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	(71)
Available-for-Sale Securities, Fair Value, Total	15,139	77,190
Available-for-Sale Securities, Gross Unrealized Losses, Total	(106)	(102)
Foreign Government Debt Securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	64,857
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(51)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0
Available-for-Sale Securities, Fair Value, Total	64,857
Available-for-Sale Securities, Gross Unrealized Losses, Total	(51)
Commercial Mortgage Backed Securities [Member]
Fair values and gross unrealized losses of the investments
Available-for-Sale Securities, Less Than 12 Months, Fair Value	165,393	141,761
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(1,706)	(878)
Available-for-Sale Securities, 12 Months or Greater, Fair Value	24,362	2,150
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(1,973)	(931)
Available-for-Sale Securities, Fair Value, Total	189,755	143,911
Available-for-Sale Securities, Gross Unrealized Losses, Total	$ (3,679)	$ (1,809)

Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale that have been in a continuous loss position for twelve months or longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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Amount of accumulated unrealized loss on investments in debt and equity securities classified as available-for-sale in a continuous loss position.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

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