MARKETABLE SECURITIES (Details) - USD ($)	3 Months Ended	6 Months Ended
	Dec. 26, 2020	Dec. 26, 2020	Jun. 27, 2020
Marketable Securities [Line Items]
Amortized Cost Basis	$ 122,670,000	$ 122,670,000	$ 107,284,000
Gross Unrealized Gains	8,397,000	8,397,000	8,983,000
Gross Unrealized Losses	(68,000)	(68,000)	0
Fair Value	130,999,000	130,999,000	116,267,000
Realized gain (loss)	0	0
Short-Term Marketable Securities
Marketable Securities [Line Items]
Fair Value	17,777,000	17,777,000	18,233,000
Long-Term Marketable Securities
Marketable Securities [Line Items]
Fair Value	113,222,000	113,222,000	98,034,000
Corporate bonds
Marketable Securities [Line Items]
Amortized Cost Basis	89,476,000	89,476,000	78,651,000
Gross Unrealized Gains	3,664,000	3,664,000	4,064,000
Gross Unrealized Losses	(68,000)	(68,000)	0
Fair Value	93,072,000	93,072,000	82,715,000
Corporate bonds | Short-Term Marketable Securities
Marketable Securities [Line Items]
Fair Value	17,777,000	17,777,000	18,233,000
Corporate bonds | Long-Term Marketable Securities
Marketable Securities [Line Items]
Fair Value	75,295,000	75,295,000	64,482,000
Government bonds
Marketable Securities [Line Items]
Amortized Cost Basis	33,194,000	33,194,000	28,633,000
Gross Unrealized Gains	4,733,000	4,733,000	4,919,000
Gross Unrealized Losses	0	0	0
Fair Value	37,927,000	37,927,000	33,552,000
Government bonds | Short-Term Marketable Securities
Marketable Securities [Line Items]
Fair Value	0	0	0
Government bonds | Long-Term Marketable Securities
Marketable Securities [Line Items]
Fair Value	$ 37,927,000	$ 37,927,000	$ 33,552,000