Temporarily Impaired Available for Sale Securities by Time Period Impaired (Detail) - USD ($) $ in Thousands	Sep. 28, 2019	Dec. 29, 2018
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 803,061	$ 699,216
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,798	6,262
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	689,985	2,646,991
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2,460	61,928
Debt Securities, Available-for-sale, Unrealized Loss Position	1,493,046	3,346,207
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	4,258	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	383,034	25,150
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	501	95
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	171,681	1,182,783
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	388	12,664
Debt Securities, Available-for-sale, Unrealized Loss Position	554,715	1,207,933
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	889	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	420,027	645,379
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,297	5,821
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	518,304	1,464,208
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	2,072	49,264
Debt Securities, Available-for-sale, Unrealized Loss Position	938,331	2,109,587
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	3,369	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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