Schedule of Cash, Cash Equivalents, Investments and Restricted Cash and Investments Unrealized Loss Positions (Detail) $ in Thousands	Sep. 27, 2015 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Unrealized Losses Less Than 12 Months - Fair Value	$ 1,028,172
Unrealized Losses Less Than 12 Months - Gross Unrealized Loss	(4,594)
Unrealized Losses 12 Months or Greater - Fair Value	47,485
Unrealized Losses 12 Months or Greater - Gross Unrealized Loss	(324)
Total - Fair Value	1,075,657
Total - Gross Unrealized Loss	(4,918)
Municipal Notes And Bonds
Schedule of Available-for-sale Securities [Line Items]
Unrealized Losses Less Than 12 Months - Fair Value	36,289
Unrealized Losses Less Than 12 Months - Gross Unrealized Loss	(71)
Total - Fair Value	36,289
Total - Gross Unrealized Loss	(71)
Corporate Notes And Bonds
Schedule of Available-for-sale Securities [Line Items]
Unrealized Losses Less Than 12 Months - Fair Value	759,706
Unrealized Losses Less Than 12 Months - Gross Unrealized Loss	(3,240)
Unrealized Losses 12 Months or Greater - Fair Value	25,380
Unrealized Losses 12 Months or Greater - Gross Unrealized Loss	(80)
Total - Fair Value	785,086
Total - Gross Unrealized Loss	(3,320)
U.S Treasury and Agencies
Schedule of Available-for-sale Securities [Line Items]
Unrealized Losses Less Than 12 Months - Fair Value	87,628
Unrealized Losses Less Than 12 Months - Gross Unrealized Loss	(110)
Total - Fair Value	87,628
Total - Gross Unrealized Loss	(110)
Mutual Funds
Schedule of Available-for-sale Securities [Line Items]
Unrealized Losses Less Than 12 Months - Fair Value	18,043
Unrealized Losses Less Than 12 Months - Gross Unrealized Loss	(525)
Total - Fair Value	18,043
Total - Gross Unrealized Loss	(525)
Government-Sponsored Enterprises
Schedule of Available-for-sale Securities [Line Items]
Unrealized Losses Less Than 12 Months - Fair Value	6,805
Unrealized Losses Less Than 12 Months - Gross Unrealized Loss	(20)
Total - Fair Value	6,805
Total - Gross Unrealized Loss	(20)
Foreign Government Bonds
Schedule of Available-for-sale Securities [Line Items]
Unrealized Losses Less Than 12 Months - Fair Value	21,102
Unrealized Losses Less Than 12 Months - Gross Unrealized Loss	(65)
Total - Fair Value	21,102
Total - Gross Unrealized Loss	(65)
Mortgage Backed Securities - Residential
Schedule of Available-for-sale Securities [Line Items]
Unrealized Losses Less Than 12 Months - Fair Value	18,279
Unrealized Losses Less Than 12 Months - Gross Unrealized Loss	(165)
Unrealized Losses 12 Months or Greater - Fair Value	1,943
Unrealized Losses 12 Months or Greater - Gross Unrealized Loss	(90)
Total - Fair Value	20,222
Total - Gross Unrealized Loss	(255)
Mortgage Backed Securities - Commercial
Schedule of Available-for-sale Securities [Line Items]
Unrealized Losses Less Than 12 Months - Fair Value	80,320
Unrealized Losses Less Than 12 Months - Gross Unrealized Loss	(398)
Unrealized Losses 12 Months or Greater - Fair Value	20,162
Unrealized Losses 12 Months or Greater - Gross Unrealized Loss	(154)
Total - Fair Value	100,482
Total - Gross Unrealized Loss	$ (552)