Assets and Liabilities Held for Sale (Details)	3 Months Ended
	Mar. 31, 2019 USD ($) restaurant	Apr. 01, 2018 USD ($)
Assets and Liabilities Held for Sale
Number of stores available to be refranchised | restaurant	40
Expected time to sell markets	12 months
Loss recognized upon transfer to held for sale	$ 0
Summary of associated assets classified as held for sale:
Cash and cash equivalents	25,000
Inventories	249,000
Property and equipment, net	4,865,000
Right-of-use assets	3,900,000
Goodwill	1,726,000
Total assets held for sale	10,765,000
Lease liabilities	4,065,000
Total liabilities held for sale	4,065,000
Income before income taxes of restaurants classified as held for sale	$ 598,000	$ 487,000