Segment Reporting: (Details)	3 Months Ended		9 Months Ended
	Sep. 24, 2016 USD ($)	Sep. 26, 2015 USD ($)	Sep. 24, 2016 USD ($) item	Sep. 26, 2015 USD ($)	Dec. 26, 2015 USD ($)
Segment Reporting
Number of reportable business segments | item			2
Total revenue	$ 16,734,300	$ 15,999,500	$ 49,214,400	$ 52,500,300
Total operating income	10,438,000	9,341,800	27,799,700	27,400,100
Total depreciation	103,300	108,600	320,600	322,800
Total identifiable assets	43,495,700		43,495,700		$ 47,406,300
Operating | Franchising
Segment Reporting
Total revenue	12,560,300	12,752,500	36,375,400	35,580,400
Total operating income	8,058,800	7,827,500	20,833,600	19,679,000
Total depreciation	79,700	85,900	248,200	255,800
Total identifiable assets	3,538,000		3,538,000		3,100,900
Operating | Leasing
Segment Reporting
Total revenue	4,174,000	3,247,000	12,839,000	16,919,900
Total operating income	2,379,200	1,514,300	6,966,100	7,721,100
Total depreciation	23,600	$ 22,700	72,400	$ 67,000
Total identifiable assets	38,089,000		38,089,000		39,687,400
Unallocated
Segment Reporting
Total identifiable assets	$ 1,868,700		$ 1,868,700		$ 4,618,000