Temporarily Impaired Available for Sale Securities by Time Period Impaired (Detail) - USD ($) $ in Thousands	Jun. 29, 2019	Dec. 29, 2018
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 31,196	$ 699,216
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	136	6,262
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	1,700,361	2,646,991
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	7,877	61,928
Debt Securities, Available-for-sale, Unrealized Loss Position	1,731,557	3,346,207
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	8,013	68,190
Nontaxable Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	25,150
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	95
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	702,766	1,182,783
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	1,359	12,664
Debt Securities, Available-for-sale, Unrealized Loss Position	702,766	1,207,933
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	1,359	12,759
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	31,196	645,379
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	136	5,821
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	997,595	1,464,208
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	6,518	49,264
Debt Securities, Available-for-sale, Unrealized Loss Position	1,028,791	2,109,587
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	6,654	55,085
Debt Securities, Restricted [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	0	28,687
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	346
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position	0	28,687
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 0	$ 346

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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-Name Accounting Standards Codification
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-Section 50
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