Segment Reporting: (Details)	3 Months Ended		6 Months Ended
	Jul. 01, 2017 USD ($)	Jun. 25, 2016 USD ($)	Jul. 01, 2017 USD ($) item	Jun. 25, 2016 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting
Number of reportable business segments | item			2
Total revenue	$ 16,749,500	$ 16,299,800	$ 34,373,300	$ 32,480,100
Total operating income	9,134,200	9,323,100	18,269,600	17,361,700
Total depreciation and amortization	90,200	108,100	188,700	217,300
Total identifiable assets	47,038,400		47,038,400		$ 48,581,600
Operating | Franchising
Segment Reporting
Total revenue	12,802,900	12,147,500	24,567,100	23,815,100
Total operating income	7,212,300	6,865,100	13,354,800	12,774,800
Total depreciation and amortization	69,100	83,700	144,900	168,500
Total identifiable assets	3,041,100		3,041,100		3,141,300
Operating | Leasing
Segment Reporting
Total revenue	3,946,600	4,152,300	9,806,200	8,665,000
Total operating income	1,921,900	2,458,000	4,914,800	4,586,900
Total depreciation and amortization	21,100	$ 24,400	43,800	$ 48,800
Total identifiable assets	41,758,100		41,758,100		42,735,600
Unallocated
Segment Reporting
Total identifiable assets	$ 2,239,200		$ 2,239,200		$ 2,704,700