Segment Reporting: (Details)	3 Months Ended								12 Months Ended
	Dec. 28, 2019 USD ($)	Sep. 28, 2019 USD ($)	Jun. 29, 2019 USD ($)	Mar. 30, 2019 USD ($)	Dec. 29, 2018 USD ($)	Sep. 29, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 28, 2019 USD ($) item	Dec. 29, 2018 USD ($)	Dec. 30, 2017 USD ($)
Segment Reporting
Number of reportable business segments | item									2
Total revenue	$ 17,882,600	$ 19,680,900	$ 17,404,200	$ 18,331,200	$ 17,071,800	$ 19,118,500	$ 18,159,800	$ 18,161,000	$ 73,298,900	$ 72,511,100	$ 69,757,300
Total operating income	10,943,000	$ 12,274,700	$ 9,846,900	$ 10,066,500	10,179,600	$ 11,435,300	$ 10,074,700	$ 10,074,200	43,131,100	41,763,800	38,805,000
Total depreciation and amortization									400,100	314,100	355,400
Total identifiable assets	61,842,200				46,663,100				61,842,200	46,663,100
Franchising | Canadian operations
Segment Reporting
Total revenue									4,700,000	4,400,000	3,800,000
Operating | Franchising
Segment Reporting
Total revenue									57,243,100	54,334,600	51,287,100
Total operating income									35,169,900	31,882,200	29,513,900
Total depreciation and amortization									281,600	240,500	271,300
Total identifiable assets	3,736,000				5,208,400				3,736,000	5,208,400
Operating | Leasing
Segment Reporting
Total revenue									16,055,800	18,176,500	18,470,200
Total operating income									7,961,200	9,881,600	9,291,100
Total depreciation and amortization									118,500	73,600	$ 84,100
Total identifiable assets	26,596,700				40,490,000				26,596,700	40,490,000
Unallocated
Segment Reporting
Total identifiable assets	$ 31,509,500				$ 964,700				$ 31,509,500	$ 964,700