FINANCIAL INSTRUMENTS - Schedule of Cash, Cash Equivalents, Investments and Restricted Cash and Investments Unrealized Loss Positions (Details) $ in Thousands	Dec. 23, 2018 USD ($)
Fair Value
Unrealized Losses Less than 12 Months	$ 115,573
Unrealized Losses 12 Months or Greater	149,144
Total	264,717
Gross Unrealized Loss
Unrealized Losses Less than 12 Months	(945)
Unrealized Losses 12 Months or Greater	(1,046)
Total	(1,991)
U.S. Treasury and agencies
Fair Value
Unrealized Losses Less than 12 Months, available for sale	6,837
Unrealized Losses 12 Months or Greater, available for sale	7,081
Total, available for sale	13,918
Gross Unrealized Loss
Unrealized Losses Less than 12 Months, available for sale	(12)
Unrealized Losses 12 Months or Greater, available for sale	(109)
Total, available for sale	(121)
Municipal notes and bonds
Fair Value
Unrealized Losses Less than 12 Months, available for sale	39,827
Unrealized Losses 12 Months or Greater, available for sale	70,527
Total, available for sale	110,354
Gross Unrealized Loss
Unrealized Losses Less than 12 Months, available for sale	(105)
Unrealized Losses 12 Months or Greater, available for sale	(157)
Total, available for sale	(262)
Mutual funds
Fair Value
Unrealized Losses Less than 12 Months, trading	33,603
Unrealized Losses 12 Months or Greater, trading	0
Total, trading	33,603
Gross Unrealized Loss
Unrealized Losses Less than 12 Months, trading	(664)
Unrealized Losses 12 Months or Greater, trading	0
Total, trading	(664)
Government-sponsored enterprises
Fair Value
Unrealized Losses Less than 12 Months, available for sale	0
Unrealized Losses 12 Months or Greater, available for sale	10,830
Total, available for sale	10,830
Gross Unrealized Loss
Unrealized Losses Less than 12 Months, available for sale	0
Unrealized Losses 12 Months or Greater, available for sale	(160)
Total, available for sale	(160)
Corporate notes and bonds
Fair Value
Unrealized Losses Less than 12 Months, available for sale	35,306
Unrealized Losses 12 Months or Greater, available for sale	60,706
Total, available for sale	96,012
Gross Unrealized Loss
Unrealized Losses Less than 12 Months, available for sale	(164)
Unrealized Losses 12 Months or Greater, available for sale	(620)
Total, available for sale	$ (784)