LEASES - Summary of Operating Lease Right of Use Assets and Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Sep. 26, 2021	Dec. 27, 2020
Lessor, Lease, Description [Line Items]
Right of use assets	$ 12,604	$ 4,469
Corporate Offices, One Company Owned Store and For Certain Restaurant Properties
Lessor, Lease, Description [Line Items]
Right of use assets	17,419	13,948
Lease liabilities	$ 20,548	$ 14,651