Summary of Refranchising and Franchise Acquisitions - Summary of Refranchising (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 24, 2020 restaurants	Jun. 16, 2020 USD ($) state restaurants	Jun. 18, 2019 USD ($) restaurants franchise	Dec. 31, 2019 USD ($)
Franchise Acquisitions [Abstract]
Company-operated restaurants sold to franchisees | restaurants	5	6	13
Proceeds from the sale of company-operated restaurants, net of selling costs		$ 2,558	$ 2,090
Net assets sold (primarily furniture, fixtures and equipment)		(2,086)	(2,051)
Goodwill related to the company-operated restaurants sold to franchisees		1,196	83
Allocation to deferred franchise fees		(193)	(281)
Sublease assets, net		220	260
Gain on lease termination		40	0
Loss on sale of company-operated restaurants		(657)	(65)
Assets Held For Sale, Assets Sold		700
Assets Held For Sale, Fair Value Adjustment		$ 600
Goodwill, Acquired During Period			2,672
Property, Plant and Equipment, Additions			578
Business combination recognized identifiable assets acquired and liabilities assumed, operating lease right of use assets			858
Business combination recognized identifiable assets acquired and liabilities assumed, operating lease liabilities			858
Below Market Lease, Acquired			130
Business Combination, Consideration Transferred			$ 3,120
Significant Changes, Franchises Purchased During Period		0	3
Other property and equipment		$ 0		$ 4,025
Goodwill		0		4,386
Assets Held-for-sale, Not Part of Disposal Group, Current, Total		1,495		8,411
Other Receivables		1,300
Land Available-for-sale		561		0
Real Estate Held-for-sale		$ 934		$ 0