Temporarily Impaired Available for Sale Securities by Time Period Impaired (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 29, 2014	Dec. 28, 2013
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	$ 1,297,361	$ 1,238,851
Less Than 12 Months, Unrealized Losses	10,922	13,642
12 Months or Longer, Fair Value	124,134	129,504
12 Months or Longer, Unrealized Losses	3,372	4,124
Total, Fair Value	1,421,495	1,368,355
Total, Unrealized Losses	14,294	17,766
Tax exempt bonds
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	678,263	502,304
Less Than 12 Months, Unrealized Losses	5,019	6,710
12 Months or Longer, Fair Value	79,159	106,985
12 Months or Longer, Unrealized Losses	2,327	3,207
Total, Fair Value	757,422	609,289
Total, Unrealized Losses	7,346	9,917
Taxable bonds
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	536,084	535,233
Less Than 12 Months, Unrealized Losses	2,052	3,347
12 Months or Longer, Fair Value	42,793	19,367
12 Months or Longer, Unrealized Losses	726	516
Total, Fair Value	578,877	554,600
Total, Unrealized Losses	2,778	3,863
Restricted investments
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value		169,914
Less Than 12 Months, Unrealized Losses		86
12 Months or Longer, Fair Value		0
12 Months or Longer, Unrealized Losses		0
Total, Fair Value		169,914
Total, Unrealized Losses		86
Equity securities
Schedule of Available-for-sale Securities [Line Items]
Less Than 12 Months, Fair Value	83,014	31,400
Less Than 12 Months, Unrealized Losses	3,851	3,499
12 Months or Longer, Fair Value	2,182	3,152
12 Months or Longer, Unrealized Losses	319	401
Total, Fair Value	85,196	34,552
Total, Unrealized Losses	$ 4,170	$ 3,900