Financial Instruments (Details) - USD ($) $ in Thousands	Jul. 01, 2017	Apr. 01, 2017
Available-for-sale securities
Amortized Cost	$ 3,705,695	$ 3,392,034
Gross Unrealized Gains	7,553	5,571
Gross Unrealized Losses	26,413	32,672
Estimated Fair Value	3,686,835	3,364,933
Money Market Funds [Member]
Available-for-sale securities
Amortized Cost	379,788	298,307
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	379,788	298,307
Financial institution securities [Member]
Available-for-sale securities
Amortized Cost	424,586	348,797
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Estimated Fair Value	424,586	348,797
Non-financial institution securities [Member]
Available-for-sale securities
Amortized Cost	433,609	409,109
Gross Unrealized Gains	700	647
Gross Unrealized Losses	335	496
Estimated Fair Value	433,974	409,260
U.S. Government and Agency Securities [Member]
Available-for-sale securities
Amortized Cost	157,433	130,749
Gross Unrealized Gains	4	8
Gross Unrealized Losses	182	223
Estimated Fair Value	157,255	130,534
Foreign Government and Agency Securities [Member]
Available-for-sale securities
Amortized Cost	394,121	322,172
Gross Unrealized Gains	3	0
Gross Unrealized Losses	0	51
Estimated Fair Value	394,124	322,121
Mortgage-Backed Securities [Member]
Available-for-sale securities
Amortized Cost	1,194,714	1,186,732
Gross Unrealized Gains	5,407	3,527
Gross Unrealized Losses	10,549	14,757
Estimated Fair Value	1,189,572	1,175,502
Asset-backed Securities [Member]
Available-for-sale securities
Amortized Cost	222,552	220,033
Gross Unrealized Gains	589	404
Gross Unrealized Losses	441	686
Estimated Fair Value	222,700	219,751
Debt Mutual Fund [Member]
Available-for-sale securities
Amortized Cost	101,350	101,350
Gross Unrealized Gains	0	0
Gross Unrealized Losses	11,453	12,674
Estimated Fair Value	89,897	88,676
Bank Loans [Member]
Available-for-sale securities
Amortized Cost	164,300	153,281
Gross Unrealized Gains	604	839
Gross Unrealized Losses	160	106
Estimated Fair Value	164,744	154,014
Commercial Mortgage Backed Securities [Member]
Available-for-sale securities
Amortized Cost	233,242	221,504
Gross Unrealized Gains	246	146
Gross Unrealized Losses	3,293	3,679
Estimated Fair Value	$ 230,195	$ 217,971

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
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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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