MARKETABLE SECURITIES - Marketable Securities (Details) - USD ($)	3 Months Ended
	Mar. 27, 2021	Jun. 27, 2020
Marketable Securities [Line Items]
Amortized Cost Basis	$ 121,177,000	$ 107,284,000
Gross Unrealized Gains	5,745,000	8,983,000
Gross Unrealized Losses	(902,000)	0
Fair Value	126,020,000	116,267,000
Realized gain (loss)	0
Short-Term Marketable Securities
Marketable Securities [Line Items]
Fair Value	14,668,000	18,233,000
Long-Term Marketable Securities
Marketable Securities [Line Items]
Fair Value	111,352,000	98,034,000
Corporate bonds
Marketable Securities [Line Items]
Amortized Cost Basis	89,551,000	78,651,000
Gross Unrealized Gains	2,560,000	4,064,000
Gross Unrealized Losses	(902,000)	0
Fair Value	91,209,000	82,715,000
Corporate bonds | Short-Term Marketable Securities
Marketable Securities [Line Items]
Fair Value	14,668,000	18,233,000
Corporate bonds | Long-Term Marketable Securities
Marketable Securities [Line Items]
Fair Value	76,541,000	64,482,000
Government bonds
Marketable Securities [Line Items]
Amortized Cost Basis	31,626,000	28,633,000
Gross Unrealized Gains	3,185,000	4,919,000
Gross Unrealized Losses	0	0
Fair Value	34,811,000	33,552,000
Government bonds | Short-Term Marketable Securities
Marketable Securities [Line Items]
Fair Value	0	0
Government bonds | Long-Term Marketable Securities
Marketable Securities [Line Items]
Fair Value	$ 34,811,000	$ 33,552,000