Contract Liabilities - Activity (Details) - USD ($)	6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019
Activity of the current and noncurrent deferred franchise revenue
Balance at beginning of period	$ 9,575,500	$ 10,177,300
Franchise and software license fees collected from franchisees, excluding amount earned as revenue during the period	473,500	598,400
Fees earned that were included in the balance at the beginning of the period	(885,600)	(956,300)
Balance at end of period	$ 9,163,400	$ 9,819,400