Quarterly Financial Data (Unaudited): (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 29, 2012	Sep. 29, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 24, 2011	Jun. 25, 2011	Mar. 26, 2011	Dec. 29, 2012	Dec. 31, 2011
Quarterly Financial Data (Unaudited):
Total Revenue	$ 13,118,200	$ 14,799,100	$ 12,192,400	$ 11,833,400	$ 13,231,800	$ 11,773,500	$ 15,224,800	$ 11,104,900	$ 51,943,100	$ 51,335,000
Income from Operations	6,962,900	8,463,500	6,026,500	5,846,200	6,905,800	6,645,700	6,084,100	5,212,000	27,299,100	24,847,600
Net income	$ 1,758,000	$ 4,259,500	$ 3,404,400	$ 3,516,000	$ 4,185,000	$ 3,483,500	$ 3,400,200	$ 3,026,300	$ 12,937,900	$ 14,095,000
Net Income Per Common Share - Basic (in dollars per share)	$ 0.35	$ 0.85	$ 0.67	$ 0.70	$ 0.84	$ 0.70	$ 0.68	$ 0.61	$ 2.57	$ 2.83
Net Income Per Common Share - Diluted (in dollars per share)	$ 0.34	$ 0.82	$ 0.65	$ 0.67	$ 0.80	$ 0.66	$ 0.65	$ 0.58	$ 2.47	$ 2.69