LEASES - Lease Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2023	Dec. 28, 2022	Dec. 29, 2021
Lessee, Lease, Description [Line Items]
Amortization of right-to-use assets	$ 75	$ 75	$ 80
Interest on lease liabilities	45	45	59
Fixed rent cost	27,984	27,542	27,623
Short-term lease cost	8	18	21
Variable lease cost	1,825	1,274	893
Sublease income	(5,570)	(4,555)	(3,823)
Total lease cost	24,367	24,399	24,853
Occupancy and other operating expenses
Lessee, Lease, Description [Line Items]
Total lease cost	23,736	23,730	24,020
General & administrative
Lessee, Lease, Description [Line Items]
Total lease cost	492	465	413
Depreciation and amortization
Lessee, Lease, Description [Line Items]
Total lease cost	75	73	78
Interest expense
Lessee, Lease, Description [Line Items]
Total lease cost	45	45	59
Closed-store reserve
Lessee, Lease, Description [Line Items]
Total lease cost	19	86	283
Property Lease
Lessee, Lease, Description [Line Items]
Amortization of right-to-use assets	73	73	78
Interest on lease liabilities	40	42	58
Fixed rent cost	27,597	26,537	26,501
Variable lease cost	546	597	539
Sublease income	(5,570)	(4,555)	(3,823)
Total lease cost	22,686	22,694	23,353
Equipment Lease
Lessee, Lease, Description [Line Items]
Amortization of right-to-use assets	2	2	2
Interest on lease liabilities	5	3	1
Fixed rent cost	387	1,005	1,122
Short-term lease cost	8	18	21
Variable lease cost	1,279	677	354
Total lease cost	$ 1,681	$ 1,705	$ 1,500