REVENUE - Schedule of Respective Liability Balances (Details) - USD ($) $ in Thousands	Sep. 27, 2023	Dec. 28, 2022
Disaggregation of Revenue [Line Items]
Gift card liability	$ 1,972	$ 2,285
Deferred revenue, current	1,180	969
Deferred revenue, long-term	16,709	14,340
Shack sales
Disaggregation of Revenue [Line Items]
Contract with customer, asset, net	7,531	8,779
Licensing receivables, net of allowance for doubtful accounts
Disaggregation of Revenue [Line Items]
Contract with customer, asset, net	$ 4,871	$ 3,918