FINANCIAL INSTRUMENTS - Schedule of Cash, Cash Equivalents, Investments and Restricted Cash and Investments Unrealized Loss Positions (Details) $ in Thousands	Dec. 27, 2020 USD ($)
Fair Value
Unrealized Losses Less than 12 Months	$ 403,094
Unrealized Losses 12 Months or Greater	5,403
Total	408,497
Gross Unrealized Loss
Unrealized Losses Less than 12 Months	(228)
Unrealized Losses 12 Months or Greater	(103)
Total	(331)
U.S. Treasury and agencies
Fair Value
Unrealized losses less than 12 months, available for sale	56,901
Unrealized losses 12 months or greater, available for sale	0
Total, available for sale	56,901
Gross Unrealized Loss
Unrealized losses less than 12 months, available for sale	(2)
Unrealized losses 12 months or greater, available for sale	0
Total, available for sale	(2)
Mutual funds
Fair Value
Unrealized losses less than 12 months, trading	0
Unrealized losses 12 months or greater, trading	5,403
Total, trading	5,403
Gross Unrealized Loss
Unrealized losses less than 12 months, trading	0
Unrealized losses 12 months or greater, trading	(103)
Total, trading	(103)
Foreign government bonds
Fair Value
Unrealized losses less than 12 months, available for sale	8,843
Unrealized losses 12 months or greater, available for sale	0
Total, available for sale	8,843
Gross Unrealized Loss
Unrealized losses less than 12 months, available for sale	(2)
Unrealized losses 12 months or greater, available for sale	0
Total, available for sale	(2)
Corporate notes and bonds
Fair Value
Unrealized losses less than 12 months, available for sale	332,902
Unrealized losses 12 months or greater, available for sale	0
Total, available for sale	332,902
Gross Unrealized Loss
Unrealized losses less than 12 months, available for sale	(221)
Unrealized losses 12 months or greater, available for sale	0
Total, available for sale	(221)
Mortgage backed securities — residential
Fair Value
Unrealized losses less than 12 months, available for sale	4,448
Unrealized losses 12 months or greater, available for sale	0
Total, available for sale	4,448
Gross Unrealized Loss
Unrealized losses less than 12 months, available for sale	(3)
Unrealized losses 12 months or greater, available for sale	0
Total, available for sale	$ (3)

Available-for-sale and Trading Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss

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