SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Fair Value (Details) - USD ($)	Sep. 26, 2020	Dec. 28, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets recorded for the investments held	$ 33,709,000	$ 36,290,000
Quoted Prices in Active Markets for Identical Assets (Level 1)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities	33,881,000	36,500,000
Derivative financial instruments, net	0	0
Significant Other Observable Inputs (Level 2)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities	0	0
Derivative financial instruments, net	3,548,000	3,247,000
Significant Unobservable Inputs (Level 3)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities	0	0
Derivative financial instruments, net	0	0
Carrying Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading Securities	33,881,000	36,500,000
Derivative financial instruments, net	3,548,000	3,247,000
Delta E M D Pty Ltd
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of remaining ownership	$ 172,000	$ 210,000