Segment Reporting: (Details)	3 Months Ended		6 Months Ended
	Jun. 27, 2020 USD ($)	Jun. 29, 2019 USD ($)	Jun. 27, 2020 USD ($) item	Jun. 29, 2019 USD ($)	Dec. 28, 2019 USD ($)
Segment Reporting
Number of reportable business segments | item			2
Total revenue	$ 12,389,500	$ 17,404,200	$ 30,989,500	$ 35,735,400
Total operating income	6,677,800	9,846,900	16,779,600	19,913,400
Total depreciation and amortization	122,900	85,900	246,000	166,000
Total identifiable assets	31,626,400		31,626,400		$ 61,842,200
Operating | Franchising
Segment Reporting
Total revenue	8,915,700	14,201,200	21,644,500	27,377,100
Total operating income	4,599,700	8,450,800	11,811,100	15,948,800
Total depreciation and amortization	72,700	67,400	145,300	129,900
Total identifiable assets	4,405,700		4,405,700		3,736,000
Operating | Leasing
Segment Reporting
Total revenue	3,473,800	3,203,000	9,345,000	8,358,300
Total operating income	2,078,100	1,396,100	4,968,500	3,964,600
Total depreciation and amortization	50,200	$ 18,500	100,700	$ 36,100
Total identifiable assets	19,834,200		19,834,200		26,596,700
Unallocated
Segment Reporting
Total identifiable assets	$ 7,386,500		$ 7,386,500		$ 31,509,500