Available for Sale Securities (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 29, 2018	Dec. 30, 2017
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 3,944,459	$ 3,926,697
Debt Securities, Available-for-sale, Unrealized Gain	2,441	1,297
Debt Securities, Available-for-sale, Unrealized Loss	68,190	41,863
Debt Securities, Available-for-sale, Fair Value	3,878,710	3,886,131
Tax exempt bonds
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	1,256,673	1,811,523
Debt Securities, Available-for-sale, Unrealized Gain	184	602
Debt Securities, Available-for-sale, Unrealized Loss	12,759	16,420
Debt Securities, Available-for-sale, Fair Value	1,244,098	1,795,705
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	2,527,468	2,115,174
Debt Securities, Available-for-sale, Unrealized Gain	1,737	695
Debt Securities, Available-for-sale, Unrealized Loss	55,085	25,443
Debt Securities, Available-for-sale, Fair Value	2,474,120	2,090,426
Debt Securities, Restricted [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	160,318	0
Debt Securities, Available-for-sale, Unrealized Gain	520	0
Debt Securities, Available-for-sale, Unrealized Loss	346	0
Debt Securities, Available-for-sale, Fair Value	$ 160,492	$ 0

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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Amount of unrealized gain on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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Amount of unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26610-111562

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-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563

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