Consolidated Statements of Shareholders' Equity (USD $)	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Total
BALANCE at Dec. 31, 2011	$ 629,800	$ 34,461,900	$ 17,000	$ 35,108,700
BALANCE (in shares) at Dec. 31, 2011	4,987,643
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock	(3,874,900)	(3,345,400)		(7,220,300)
Repurchase of common stock (in shares)	(134,720)
Stock options exercised and related tax benefits	2,314,900			2,314,900
Stock options exercised and related tax benefits (in shares)	143,536
Compensation expense relating to stock options	930,200			930,200
Cash dividends		(26,122,400)		(26,122,400)
Comprehensive income (loss)		12,937,900	(21,000)	12,916,900
BALANCE at Dec. 29, 2012		17,932,000	(4,000)	17,928,000
BALANCE (in shares) at Dec. 29, 2012	4,996,459
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock	(1,854,900)			(1,854,900)
Repurchase of common stock (in shares)	(28,422)
Stock options exercised and related tax benefits	3,650,800			3,650,800
Stock options exercised and related tax benefits (in shares)	175,493
Compensation expense relating to stock options	1,153,600			1,153,600
Cash dividends		(964,300)		(964,300)
Comprehensive income (loss)		18,231,600	(100)	18,231,500
BALANCE at Dec. 28, 2013	2,949,500	35,199,300	(4,100)	38,144,700
BALANCE (in shares) at Dec. 28, 2013	5,143,530			5,143,530
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of common stock	(4,453,400)	(7,111,400)		(11,564,800)
Repurchase of common stock (in shares)	(166,030)
Stock options exercised and related tax benefits	509,100			509,100
Stock options exercised and related tax benefits (in shares)	21,012
Compensation expense relating to stock options	1,417,200			1,417,200
Cash dividends		(26,930,200)		(26,930,200)
Comprehensive income (loss)		20,066,500	(33,000)	20,033,500
BALANCE at Dec. 27, 2014	$ 422,400	$ 21,224,200	$ (37,100)	$ 21,609,500
BALANCE (in shares) at Dec. 27, 2014	4,998,512			4,998,512