Quarterly Financial Data (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 28, 2019	Sep. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Quarterly Financial Data (Unaudited):
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
Income from Operations	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
Net Income	$ 8,461,400	$ 9,113,800	$ 7,301,900	$ 7,272,200	$ 7,657,800	$ 8,364,300	$ 7,143,000	$ 6,960,400	$ 32,149,300	$ 30,125,500	$ 24,580,500
Net Income Per Common Share - Basic	$ 2.18	$ 2.39	$ 1.94	$ 1.86	$ 1.96	$ 2.15	$ 1.85	$ 1.81	$ 8.37	$ 7.77	$ 6.06
Net Income Per Common Share - Diluted	$ 2.08	$ 2.24	$ 1.79	$ 1.73	$ 1.83	$ 2.01	$ 1.73	$ 1.69	$ 7.84	$ 7.26	$ 5.66