Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 30, 2017	Apr. 01, 2017
Available-for-sale securities
Amortized Cost	$ 3,606,600	$ 3,392,034
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	5,191	5,571
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(33,072)	(32,672)
Estimated Fair Value	3,578,719	3,364,933
Money Market Funds [Member]
Available-for-sale securities
Amortized Cost	279,946	298,307
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Estimated Fair Value	279,946	298,307
Financial institution securities [Member]
Available-for-sale securities
Amortized Cost	499,996	348,797
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	0
Estimated Fair Value	499,996	348,797
Non-financial institution securities [Member]
Available-for-sale securities
Amortized Cost	395,795	409,109
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	259	647
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(790)	(496)
Estimated Fair Value	395,264	409,260
Auction Rate Securities [Member]
Available-for-sale securities
Estimated Fair Value	0
U.S. Government and Agency Securities [Member]
Available-for-sale securities
Amortized Cost	198,416	130,749
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	13	8
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(226)	(223)
Estimated Fair Value	198,203	130,534
Foreign Government and Agency Securities [Member]
Available-for-sale securities
Amortized Cost	300,776	322,172
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	0	(51)
Estimated Fair Value	300,776	322,121
Mortgage-Backed Securities [Member]
Available-for-sale securities
Amortized Cost	1,193,776	1,186,732
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	3,874	3,527
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(15,324)	(14,757)
Estimated Fair Value	1,182,326	1,175,502
Asset-backed Securities [Member]
Available-for-sale securities
Amortized Cost	224,276	220,033
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	346	404
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(1,007)	(686)
Estimated Fair Value	223,615	219,751
Debt Mutual Fund [Member]
Available-for-sale securities
Amortized Cost	101,350	101,350
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(11,439)	(12,674)
Estimated Fair Value	89,911	88,676
Bank Loans [Member]
Available-for-sale securities
Amortized Cost	163,230	153,281
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	631	839
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(188)	(106)
Estimated Fair Value	163,673	154,014
Commercial Mortgage Backed Securities [Member]
Available-for-sale securities
Amortized Cost	241,539	221,504
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	68	146
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(2,534)	(3,679)
Estimated Fair Value	239,073	217,971
Equity Securities [Member]
Available-for-sale securities
Amortized Cost	7,500	0
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0	0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	(1,564)	0
Estimated Fair Value	$ 5,936	$ 0

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=75030427&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 45
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-Publisher FASB
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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