SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Restaurant Revenue and Advertising Costs (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2025 USD ($) restaurant	Dec. 25, 2024 USD ($)	Dec. 27, 2023 USD ($)
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Promotional allowances amount	$ 9,800	$ 6,300	$ 8,700
Loyalty Rewards Program, Expiration Period For Inactivity	1 year
Accrued loyalty rewards program liability	$ 1,100	800
Loyalty Rewards Program, Expected Loyalty Points Redemption Period	1 year
Number of franchised restaurants committed to open | restaurant	88
Advertising expense	$ 16,900	16,100	16,200
Accrued advertising	2,438	1,194
Accrued advertising obligated to spend in future	$ 2,400
Initial lease term	20 years
Minimum
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	10 years
Percentage of monthly franchise fee	4.00%
Maximum
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period	20 years
Percentage of monthly franchise fee	5.00%
Hardware Services
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Unsatisfied performance obligations	$ 0
Franchise Rights
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Renewal period	20 years
Franchise agreement term	20 years
General and Administrative Expense
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Preopening costs	$ 100	100	100
Franchised
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Advertising fees	$ 31,800	$ 31,200	$ 29,200