Revenue Recognition (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Jan. 01, 2019	Jan. 02, 2018	Jul. 03, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Gift card liability	$ 2,398	$ 3,284		$ 300
Revenue recognized	5,300	5,900	$ 5,500
Gift card breakage	$ 400	1,000	$ 300
Period in which initial fees received from franchisees will be recognized as revenue	20 years
Retained earnings	$ (115,480)	(111,135)
Accrued expenses and other current liabilities
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Gift card liability	2,400	3,300
Other long-term liabilities
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Gift card liability, non-current	900	400
Calculated under Revenue Guidance in Effect on Adoption of Topic 606 | ASU No. 2014-09
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue recognized	$ 200
Retained earnings		$ 1,500